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  • Artikel  (534)
  • Artikel: DFG Deutsche Nationallizenzen  (534)
  • Annual Reviews  (534)
  • Geologie und Paläontologie  (534)
  • Sociologie
  • 1
    Digitale Medien
    Digitale Medien
    ATMOSPHERIC MOIST CONVECTION (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 605-643 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Various forms of atmospheric moist convection are reviewed through a consideration of three prevalent regimes: stratocumulus; trade-wind; and deep, precipitating, maritime convection. These regimes are chosen because they are structural components of the general circulation of the atmosphere and because they highlight distinguishing features of this polymorphous phenomenon. In particular, the ways in which varied forms of moist convection communicate with remote parts of the flow through mechanisms other than the rearrangement of fluid parcels are emphasized. These include radiative, gravity wave, and/or microphysical (precipitation) processes. For each regime, basic aspects of its phenomenology are presented along with theoretical frameworks that have arisen to help rationalize the phenomenology. Recent developments suggest that the increased capacity for numerical simulation and increasingly refined remote sensing capabilities bodes well for major advances in the coming years.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122658
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  • 2
    Digitale Medien
    Digitale Medien
    VOLCANIC SEISMOLOGY (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 461-491 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Recent developments in volcanic seismology include new techniques to improve earthquake locations that have changed clouds of earthquakes to lines (faults) for high-frequency events and small volumes for low-frequency (LF) events. Spatial mapping of the b-value shows regions of normal b and high b anomalies at depths of 3-4 and 7-10 km. Increases in b precede some eruptions. LF events and very-long-period (VLP) events have been recorded at many volcanoes, and models are becoming increasingly sophisticated. Deep long-period (LP) events are fairly common, but may represent several processes. Acoustic sensors have greatly improved the study of volcanic explosions. Volcanic tremor is stronger for fissure eruptions, phreatic eruptions, and higher gas contents. Path and site effects can be extreme at volcanoes. Seismicity at volcanoes is triggered by large earthquakes, although mechanisms are still uncertain. A number of volcanoes have significant deformation with very little seismicity. Tomography has benefited from improved techniques and better instrumental arrays.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122459
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  • 3
    Digitale Medien
    Digitale Medien
    PLANETARY SEISMOLOGY (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 571-604 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Contrary to Earth, the interior of terrestrial planets is poorly known. This is mainly related to the lack of seismic data and of planetary seismic networks on these planets. So far, despite several attempts, only the Apollo Seismic Network has returned seismic information from the Moon. But even in this case, very few seismic signals were recorded after a propagation path through the deep interior and core owing to a hemispheric distribution of the stations on the near side and to a probably strongly attenuating lower mantle. This review presents the main results achieved by the analysis of the Apollo seismic data and the associated constraints on the internal structure of the Moon. It then presents the current knowledge on the Martian interior, the seismic activity of the planet, and possible source of seismic noise. This information can be used for preparing future Martian seismic network missions. A short review on existing space-qualified instruments and on possible seismic missions toward other telluric bodies, such as Venus, the giant planets' satellites, or small bodies, is then given.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122604
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  • 4
    Digitale Medien
    Digitale Medien
    THE INTERIORS OF GIANT PLANETS: Models and Outstanding Questions (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 493-530 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: We know that giant planets played a crucial role in the making of our Solar System. The discovery of giant planets orbiting other stars is a formidable opportunity to learn more about these objects, what their composition is, how various processes influence their structure and evolution, and most importantly how they form. Jupiter, Saturn, Uranus, and Neptune can be studied in detail, mostly from close spacecraft flybys. We can infer that they are all enriched in heavy elements compared to the Sun, with the relative global enrichments increasing with distance to the Sun. We can also infer that they possess dense cores of varied masses. The intercomparison of presently characterized extrasolar giant planets shows that they are also mainly made of hydrogen and helium, but that they either have significantly different amounts of heavy elements, have had different orbital evolutions, or both. Hence, many questions remain and need to be answered to make significant progress on the origins of planets.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120325
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  • 5
    Digitale Medien
    Digitale Medien
    OROGRAPHIC PRECIPITATION (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 645-671 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The influence of surface orography on patterns of precipitation gives rise to some of the most pronounced climate gradients on Earth, and plays a fundamental role in the interaction between the atmosphere and the rest of the Earth System on a wide variety of time scales. The physical mechanisms involved comprise a rich set of interactions encompassing fluid dynamics, thermodynamics, and micron-scale cloud processes, as well as being dependent on the larger-scale patterns of the atmospheric general circulation. Investigations into orographic precipitation have pursued three parallel tracks of inquiry: observations, theory, and modeling. Significant advances have been made in each over the last few decades, and these are summarized and synthesized here. While many aspects of the basic mechanisms responsible for orographic precipitation have been understood, important issues remain unresolved. The sheer number of contributing processes, together with their convoluted interactions, make the quantitative prediction of precipitation in complex terrain a very hard task. However, while prediction of precipitation amounts for any given event may be difficult, various lines of evidence suggest that the patterns of orgraphic precipitation, even on scales of a few kilometers, are much more robust.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122541
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  • 6
    Digitale Medien
    Digitale Medien
    EARLY CRUSTAL EVOLUTION OF MARS 1 (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 133-161 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The bulk of the Đ♯50-km-thick Martian crust formed at Đ♯4.5 Gyr B.P., perhaps from a magma ocean. This crust is probably a basaltic andesite or andesite and is enriched in incompatible and heat-producing elements. Later additions of denser basalt to the crust were volumetrically minor, but resurfaced significant portions of the Northern hemisphere. A significant fraction of the total thickness of the crust was magnetized prior to 4 Gyr B.P., with the magnetization later selectively removed by large impacts. Early large impacts also modified the hemispheric contrast in crustal thickness (the dichotomy), which was possibly caused by long-wavelength mantle convection. Subsequent Noachian modification of the crust included further impacts, significant fluvial erosion, and volcanism associated with the formation of the Tharsis rise. Remaining outstanding questions include the origin of the dichotomy and the nature of the magnetic anomalies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122637
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  • 7
    Digitale Medien
    Digitale Medien
    SUBGLACIAL PROCESSES (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 247-276 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Processes operating beneath glaciers can have a greater influence on flow dynamics than those operating within them. The variety and complexity of these processes, which involve interactions among ice, water, and geological solids, resist efforts to establish simple truths and can lead to surprising outcomes. Thermal conditions at the ice-bed interface (melting or nonmelting) and the mechanical properties of the glacier substrate (soft or hard) determine which processes can be activated. The warm-soft case supports the greatest variety of processes and is the most important for fast-flow dynamics and for the mobilization of subglacial sediment. Process interactions can lead to oscillations and spatio-temporal switching behavior in glaciers and ice sheets as well as to the generation of subglacial landforms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122621
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  • 8
    Digitale Medien
    Digitale Medien
    THE EDIACARA BIOTA: Neoproterozoic Origin of Animals and Their Ecosystems (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 421-442 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The Ediacara biota (575Đ??542 Ma) marks the first appearance of large, architecturally complex organisms in Earth history. Present evidence suggests that the Ediacara biota included a mixture of stem- and crown-group radial animals, stem-group bilaterian animals, "failed experiments" in animal evolution, and perhaps representatives of other eukaryotic kingdoms. These soft-bodied organisms were preserved under (or rarely within) event beds of sand or volcanic ash, and four distinct preservational styles (Flinders-, Fermeuse-, Conception-, and Nama-style) profoundly affected the types of organisms and features that could be preserved. Even the earliest Ediacaran communities (575Đ??565 Ma) show vertical and lateral niche subdivision of the sessile, benthic, filter-feeding organisms, which is strikingly like that of Phanerozoic and modern communities. Later biological and ecological innovations include mobility (〉555 Ma), calcification (550 Ma), and predation (〈549 Ma). The Ediacara biota abruptly disappeared 542 million years ago, probably as a consequence of mass extinction andor biological interactions with the rapidly evolving animals of the Cambrian explosion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122519
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  • 9
    Digitale Medien
    Digitale Medien
    PLANETARY SEISMOLOGY (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 571-604 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Contrary to Earth, the interior of terrestrial planets is poorly known. This is mainly related to the lack of seismic data and of planetary seismic networks on these planets. So far, despite several attempts, only the Apollo Seismic Network has returned seismic information from the Moon. But even in this case, very few seismic signals were recorded after a propagation path through the deep interior and core owing to a hemispheric distribution of the stations on the near side and to a probably strongly attenuating lower mantle. This review presents the main results achieved by the analysis of the Apollo seismic data and the associated constraints on the internal structure of the Moon. It then presents the current knowledge on the Martian interior, the seismic activity of the planet, and possible source of seismic noise. This information can be used for preparing future Martian seismic network missions. A short review on existing space-qualified instruments and on possible seismic missions toward other telluric bodies, such as Venus, the giant planets' satellites, or small bodies, is then given.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122604
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  • 10
    Digitale Medien
    Digitale Medien
    SUBGLACIAL PROCESSES (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 247-276 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Processes operating beneath glaciers can have a greater influence on flow dynamics than those operating within them. The variety and complexity of these processes, which involve interactions among ice, water, and geological solids, resist efforts to establish simple truths and can lead to surprising outcomes. Thermal conditions at the ice-bed interface (melting or nonmelting) and the mechanical properties of the glacier substrate (soft or hard) determine which processes can be activated. The warm-soft case supports the greatest variety of processes and is the most important for fast-flow dynamics and for the mobilization of subglacial sediment. Process interactions can lead to oscillations and spatio-temporal switching behavior in glaciers and ice sheets as well as to the generation of subglacial landforms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122621
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  • 11
    Digitale Medien
    Digitale Medien
    MOLECULAR APPROACHES TO MARINE MICROBIAL ECOLOGY AND THE MARINE NITROGEN CYCLE (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 301-333 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Microbes are recognized as important components of the Earth system, playing key roles in controlling the composition of the atmosphere and surface waters, forming the basis of the marine food web, and the cycling of chemicals in the ocean. A revolution in microbial ecology has occurred in the past 15Đ??20 years with the advent of rapid methods for discovering and sequencing the genes of uncultivated microbes from natural environments. Initially based on sequences from the 16S rRNA gene, this revolution made it possible to identify microorganisms without first cultivating them, to discover and characterize the immense previously unsuspected diversity of the microbial world, and to reconstruct the evolutionary relationships among microbes. Subsequent focus on functional genes, those that encode enzymes that catalyze biogeochemical transformations, and current work on larger DNA fragments and entire genomes make it possible to link microbial diversity to ecosystem function. These approaches have yielded insights into the regulation of microbial activity and proof of the microbial role in biogeochemical processes previously unknown. Questions raised by the molecular revolution, which are now the focus of microbial ecology research, include the significance of microbial diversity and redundancy to biogeochemical processes and ecosystem function.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122514
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  • 12
    Digitale Medien
    Digitale Medien
    THE EARLY HISTORY OF ATMOSPHERIC OXYGEN: Homage to Robert M. Garrels (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 1-36 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: This paper reviews the Precambrian history of atmospheric oxygen, beginning with a brief discussion of the possible nature and magnitude of life before the evolution of oxygenic photosynthesis. This is followed by a summary of the various lines of evidence constraining oxygen levels through time, resulting in a suggested history of atmospheric oxygen concentrations. Also reviewed are the various processes regulating oxygen concentrations, and several models of Precambrian oxygen evolution are presented. A sparse geologic record, combined with uncertainties as to its interpretation, yields only a fragmentary and imprecise reading of atmospheric oxygen evolution. Nevertheless, oxygen levels have increased through time, but not monotonically, with major and fascinating swings to both lower and higher levels.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122711
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  • 13
    Digitale Medien
    Digitale Medien
    REAL-TIME SEISMOLOGY AND EARTHQUAKE DAMAGE MITIGATION (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 195-214 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Real-time seismology refers to a practice in which seismic data are collected and analyzed quickly after a significant seismic event, so that the results can be effectively used for postearthquake emergency response and early warning. As the technology of seismic instrumentation, telemetry, computers, and data storage facility advances, the real-time seismology for rapid postearthquake notification is essentially established. Research for early warning is still underway. Two approaches are possible: (a) regional warning and (b) on-site (or site-specific) warning. In (a), the traditional seismological method is used to locate an earthquake, determine the magnitude, and estimate the ground motion at other sites. In (b), the beginning of the ground motion (mainly P wave) observed at a site is used to predict the ensuing ground motion at the same site. An effective approach to on-site warning is discussed in light of earthquake rupture physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122626
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  • 14
    Digitale Medien
    Digitale Medien
    EVOLUTION OF THE CONTINENTAL LITHOSPHERE (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 369-393 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Stable cratons and stable continental platforms are salient features of the Earth. Mantle xenoliths provide detailed data on deep structure. Cratonal lithosphere is about 200 km thick. It formed in the Archean by processes analogous to modern tectonics and has been stable beneath the larger cratons since that time. Its high viscosity, high yield strength, and chemical buoyancy protected it from being entrained by underlying stagnant lid convection and by subduction. Chemically buoyant mantle does not underlie platforms. Platform lithosphere has gradually thickened with time as convection waned as the Earth's interior cooled. The thermal contraction associated with this thickening causes platforms to subside relative to cratons. At present, the thickness of platform lithosphere is comparable to that of cratonal lithosphere.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122643
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  • 15
    Digitale Medien
    Digitale Medien
    EARTHQUAKE TRIGGERING BY STATIC, DYNAMIC, AND POSTSEISMIC STRESS TRANSFER (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 335-367 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Earthquake triggering is the process by which stress changes associated with an earthquake can induce or retard seismic activity in the surrounding region or trigger other earthquakes at great distances. Calculations of static Coulomb stress changes associated with earthquake slip have proven to be a powerful tool in explaining many seismic observations, including aftershock distributions, earthquake sequences, and the quiescence of broad, normally active regions following large earthquakes. Delayed earthquake triggering, which can range from seconds to decades, can be explained by a variety of time-dependent stress transfer mechanisms, such as viscous relaxation, poroelastic rebound, or afterslip, or by reductions in fault friction, such as predicted by rate and state constitutive relations. Rapid remote triggering of earthquakes at great distances (from several fault lengths to 1000s of km) is best explained by the passage of transient (dynamic) seismic waves, which either immediately induce Coulomb-type failure or initiate a secondary mechanism that induces delayed triggering. The passage of seismic waves may also play a significant role in the triggering of near-field earthquakes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122505
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  • 16
    Digitale Medien
    Digitale Medien
    Mathematical Modeling of Whole Landscape Evolution (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 443-459 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The mathematical modeling of landform evolution consists of two components: the processes represented (i.e., considered dominant) in the model and the (typically computer) model representation of these processes. This review discusses the current debates surrounding processes represented in landform evolution. The potential impact on both evolving landforms and computer model structure is discussed. Issues specifically discussed include (a) the fundamental nature of mass conservation and the role of detachment- and transport-limited processes in mass conservation equations, (b) the interaction between detachment- and transport-limitation in channels, (c) the role of hillslope erosion and soil properties and their interaction with channel processes, (d) the interactions with tectonics when applying these models at large scale, (e) depositional structures and implications for paleo-climatic interpretation, (f) engineering applications of these models, and (g) numerical issues in the computer implementations. This review is not a model comparison. However, many applications are at the boundaries of computer capabilities so a comparison of existing models is provided.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122610
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  • 17
    Digitale Medien
    Digitale Medien
    THE Hf-W ISOTOPIC SYSTEM AND THE ORIGIN OF THE EARTH AND MOON (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 531-570 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The Earth has a radiogenic W-isotopic composition compared to chondrites, demonstrating that it formed while 182Hf (half-life 9 Myr) was extant in Earth and decaying to 182W. This implies that Earth underwent early and rapid accretion and core formation, with most of the accumulation occurring in Đ♯10 Myr, and concluding approximately 30 Myr after the origin of the Solar System. The Hf-W data for lunar samples can be reconciled with a major Moon-forming impact that terminated the terrestrial accretion process Đ♯30 Myr after the origin of the Solar System. The suggestion that the proto-Earth to impactor mass ratio was 7:3 and occurred during accretion is inconsistent with the W isotope data. The W isotope data is satisfactorily modeled with a Mars-sized impactor on proto-Earth (proto-Earth to impactor ratio of 9:1) to form the Moon at Đ♯30 Myr.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122614
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  • 18
    Digitale Medien
    Digitale Medien
    OROGRAPHIC PRECIPITATION (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 645-671 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The influence of surface orography on patterns of precipitation gives rise to some of the most pronounced climate gradients on Earth, and plays a fundamental role in the interaction between the atmosphere and the rest of the Earth System on a wide variety of time scales. The physical mechanisms involved comprise a rich set of interactions encompassing fluid dynamics, thermodynamics, and micron-scale cloud processes, as well as being dependent on the larger-scale patterns of the atmospheric general circulation. Investigations into orographic precipitation have pursued three parallel tracks of inquiry: observations, theory, and modeling. Significant advances have been made in each over the last few decades, and these are summarized and synthesized here. While many aspects of the basic mechanisms responsible for orographic precipitation have been understood, important issues remain unresolved. The sheer number of contributing processes, together with their convoluted interactions, make the quantitative prediction of precipitation in complex terrain a very hard task. However, while prediction of precipitation amounts for any given event may be difficult, various lines of evidence suggest that the patterns of orgraphic precipitation, even on scales of a few kilometers, are much more robust.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122541
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  • 19
    Digitale Medien
    Digitale Medien
    REAL-TIME SEISMOLOGY AND EARTHQUAKE DAMAGE MITIGATION (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 195-214 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Real-time seismology refers to a practice in which seismic data are collected and analyzed quickly after a significant seismic event, so that the results can be effectively used for postearthquake emergency response and early warning. As the technology of seismic instrumentation, telemetry, computers, and data storage facility advances, the real-time seismology for rapid postearthquake notification is essentially established. Research for early warning is still underway. Two approaches are possible: (a) regional warning and (b) on-site (or site-specific) warning. In (a), the traditional seismological method is used to locate an earthquake, determine the magnitude, and estimate the ground motion at other sites. In (b), the beginning of the ground motion (mainly P wave) observed at a site is used to predict the ensuing ground motion at the same site. An effective approach to on-site warning is discussed in light of earthquake rupture physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122626
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  • 20
    Digitale Medien
    Digitale Medien
    EVOLUTION OF THE CONTINENTAL LITHOSPHERE (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 369-393 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Stable cratons and stable continental platforms are salient features of the Earth. Mantle xenoliths provide detailed data on deep structure. Cratonal lithosphere is about 200 km thick. It formed in the Archean by processes analogous to modern tectonics and has been stable beneath the larger cratons since that time. Its high viscosity, high yield strength, and chemical buoyancy protected it from being entrained by underlying stagnant lid convection and by subduction. Chemically buoyant mantle does not underlie platforms. Platform lithosphere has gradually thickened with time as convection waned as the Earth's interior cooled. The thermal contraction associated with this thickening causes platforms to subside relative to cratons. At present, the thickness of platform lithosphere is comparable to that of cratonal lithosphere.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122643
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  • 21
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    THE EDIACARA BIOTA: Neoproterozoic Origin of Animals and Their Ecosystems (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 421-442 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The Ediacara biota (575Đ??542 Ma) marks the first appearance of large, architecturally complex organisms in Earth history. Present evidence suggests that the Ediacara biota included a mixture of stem- and crown-group radial animals, stem-group bilaterian animals, "failed experiments" in animal evolution, and perhaps representatives of other eukaryotic kingdoms. These soft-bodied organisms were preserved under (or rarely within) event beds of sand or volcanic ash, and four distinct preservational styles (Flinders-, Fermeuse-, Conception-, and Nama-style) profoundly affected the types of organisms and features that could be preserved. Even the earliest Ediacaran communities (575-565 Ma) show vertical and lateral niche subdivision of the sessile, benthic, filter-feeding organisms, which is strikingly like that of Phanerozoic and modern communities. Later biological and ecological innovations include mobility (〉555 Ma), calcification (550 Ma), and predation (〈549 Ma). The Ediacara biota abruptly disappeared 542 million years ago, probably as a consequence of mass extinction andor biological interactions with the rapidly evolving animals of the Cambrian explosion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122519
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  • 22
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    THE Hf-W ISOTOPIC SYSTEM AND THE ORIGIN OF THE EARTH AND MOON (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 531-570 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The Earth has a radiogenic W-isotopic composition compared to chondrites, demonstrating that it formed while 182Hf (half-life 9 Myr) was extant in Earth and decaying to 182W. This implies that Earth underwent early and rapid accretion and core formation, with most of the accumulation occurring in Đ♯10 Myr, and concluding approximately Đ♯30 Myr after the origin of the Solar System. The Hf-W data for lunar samples can be reconciled with a major Moon-forming impact that terminated the terrestrial accretion process 30 Myr after the origin of the Solar System. The suggestion that the proto-Earth to impactor mass ratio was 7:3 and occurred during accretion is inconsistent with the W isotope data. The W isotope data is satisfactorily modeled with a Mars-sized impactor on proto-Earth (proto-Earth to impactor ratio of 9:1) to form the Moon at Đ♯30 Myr.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122614
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  • 23
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    THE EARLY HISTORY OF ATMOSPHERIC OXYGEN: Homage to Robert M. Garrels (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 1-36 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: This paper reviews the Precambrian history of atmospheric oxygen, beginning with a brief discussion of the possible nature and magnitude of life before the evolution of oxygenic photosynthesis. This is followed by a summary of the various lines of evidence constraining oxygen levels through time, resulting in a suggested history of atmospheric oxygen concentrations. Also reviewed are the various processes regulating oxygen concentrations, and several models of Precambrian oxygen evolution are presented. A sparse geologic record, combined with uncertainties as to its interpretation, yields only a fragmentary and imprecise reading of atmospheric oxygen evolution. Nevertheless, oxygen levels have increased through time, but not monotonically, with major and fascinating swings to both lower and higher levels.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122711
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  • 24
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    Digitale Medien
    REPRESENTING MODEL UNCERTAINTY IN WEATHER AND CLIMATE PREDICTION (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 163-193 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Weather and climate predictions are uncertain, because both forecast initial conditions and the computational representation of the known equations of motion are uncertain. Ensemble prediction systems provide the means to estimate the flow-dependent growth of uncertainty during a forecast. Sources of uncertainty must therefore be represented in such systems. In this paper, methods used to represent model uncertainty are discussed. It is argued that multimodel and related ensembles are vastly superior to corresponding single-model ensembles, but do not provide a comprehensive representation of model uncertainty. A relatively new paradigm is discussed, whereby unresolved processes are represented by computationally efficient stochastic-dynamic schemes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122552
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  • 25
    Digitale Medien
    Digitale Medien
    FEATHERED DINOSAURS (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 277-299 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Recent fossil discoveries from Early Cretaceous rocks of Liaoning Province, China, have provided a wealth of spectacular specimens. Included in these are the remains of several different kinds of small theropod dinosaurs, many of which are extremely closely related to modern birds. Unique preservation conditions allowed soft tissues of some of these specimens to be preserved. Many dinosaur specimens that preserve feathers and other types of integumentary coverings have been recovered. These fossils show a progression of integumentary types from simple fibers to feathers of modern aspect. The distribution of these features on the bodies of these animals is surprising in that some show large tail plumes, whereas others show the presence of wing-like structures on both fore and hind limbs. The phylogenetic distribution of feather types is highly congruent with models of feather evolution developed from developmental biology.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122511
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  • 26
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    Digitale Medien
    EVOLUTION OF FISH-SHAPED REPTILES (REPTILIA: ICHTHYOPTERYGIA) IN THEIR PHYSICAL ENVIRONMENTS AND CONSTRAINTS (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 395-420 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Ichthyosaurs were a group of Mesozoic marine reptiles that evolved fish-shaped body outlines. They are unique in several anatomical characters, including the possession of enormous eyeballs sometimes exceeding 25 cm and an enlarged manus with sometimes up to 20 bones in a single digit, or 10 digits per manus. They are also unique in that their biology has been studied from the perspective of physical constraints, which allowed estimation of such characteristics as optimal cruising speed, visual sensitivity, and even possible basal metabolic rate ranges. These functional inferences, although based on physical principles, obviously contain errors arising from the limitations of fossilized data, but are necessarily stronger than the commonly made inferences based on superficial correlations among quantities without mechanical or optical explanations for why such correlations exist.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122707
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  • 27
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    Digitale Medien
    THE INTERIORS OF GIANT PLANETS: Models and Outstanding Questions (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 493-530 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: We know that giant planets played a crucial role in the making of our Solar System. The discovery of giant planets orbiting other stars is a formidable opportunity to learn more about these objects, what their composition is, how various processes influence their structure and evolution, and most importantly how they form. Jupiter, Saturn, Uranus, and Neptune can be studied in detail, mostly from close spacecraft flybys. We can infer that they are all enriched in heavy elements compared to the Sun, with the relative global enrichments increasing with distance to the Sun. We can also infer that they possess dense cores of varied masses. The intercomparison of presently characterized extrasolar giant planets shows that they are also mainly made of hydrogen and helium, but that they either have significantly different amounts of heavy elements, have had different orbital evolutions, or both. Hence, many questions remain and need to be answered to make significant progress on the origins of planets. Pourquoi l'azur muet et l'espace insondable? Pourquoi les astres d'or fourmillant comme un sable? Arthur RimbaudĐ??Soleil et chair
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120325
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  • 28
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    Digitale Medien
    ARE THE ALPS COLLAPSING? (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 113-132 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Orogenic collapse is a process that transfers gravitational potential energy from regions of high potential energy to regions of lower potential energy. This transfer is classically considered to be accomplished by extension in the orogenic core and by synchronous shortening in foreland regions of the orogen. Not all extensional features in collisional mountain belts need, however, reflect orogenic collapse. Normal faulting, thrust faulting, and strike-slip faulting are all active in different parts of the Alps today and reflect complex local responses to ongoing Europe-Adria convergence. The Western Alps is the only area today where extension and shortening radial to orogen trend occur synchronously and where orogenic collapse may be an important process. Elsewhere in the Alps, normal faults are oriented at a high angle to orogen trend and were primarily active in Oligocene and Miocene time. Most present-day activity in the Central and Eastern Alps is on strike-slip faults that are accommodating lateral extrusion of material rather than orogenic collapse.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122535
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  • 29
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    Digitale Medien
    EARLY CRUSTAL EVOLUTION OF MARS (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 133-161 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The bulk of the Đ♯50-km-thick Martian crust formed at Đ♯4.5 Gyr B.P., perhaps from a magma ocean. This crust is probably a basaltic andesite or andesite and is enriched in incompatible and heat-producing elements. Later additions of denser basalt to the crust were volumetrically minor, but resurfaced significant portions of the Northern hemisphere. A significant fraction of the total thickness of the crust was magnetized prior to 4 Gyr B.P., with the magnetization later selectively removed by large impacts. Early large impacts also modified the hemispheric contrast in crustal thickness (the dichotomy), which was possibly caused by long-wavelength mantle convection. Subsequent Noachian modification of the crust included further impacts, significant fluvial erosion, and volcanism associated with the formation of the Tharsis rise. Remaining outstanding questions include the origin of the dichotomy and the nature of the magnetic anomalies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122637
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  • 30
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    Digitale Medien
    REPRESENTING MODEL UNCERTAINTY IN WEATHER AND CLIMATE PREDICTION (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 163-193 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Weather and climate predictions are uncertain, because both forecast initial conditions and the computational representation of the known equations of motion are uncertain. Ensemble prediction systems provide the means to estimate the flow-dependent growth of uncertainty during a forecast. Sources of uncertainty must therefore be represented in such systems. In this paper, methods used to represent model uncertainty are discussed. It is argued that multimodel and related ensembles are vastly superior to corresponding single-model ensembles, but do not provide a comprehensive representation of model uncertainty. A relatively new paradigm is discussed, whereby unresolved processes are represented by computationally efficient stochastic-dynamic schemes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122552
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  • 31
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    THE NORTH ANATOLIAN FAULT: A NEW LOOK (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 37-112 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Dedicated to the memory of three pioneers, I??hsan Ketin, Srr Erinc?? and Melih Tokay, and a recent student, Aykut Barka, who burnt himself out in pursuit of the mysteries of the North Anatolian Fault. The North Anatolian Fault (NAF) is a 1200-km-long dextral strike-slip fault zone that formed by progressive strain localization in a generally westerly widening right-lateral keirogen in northern Turkey mostly along an interface juxtaposing subduction-accretion material to its south and older and stiffer continental basements to its north. The NAF formed approximately 13 to 11 Ma ago in the east and propagated westward. It reached the Sea of Marmara no earlier than 200 ka ago, although shear-related deformation in a broad zone there had already commenced in the late Miocene. The fault zone has a very distinct morphological expression and is seismically active. Since the seventeenth century, it has shown cyclical seismic behavior, with century-long cycles beginning in the east and progressing westward. For earlier times, the record is less clear but does indicate a lively seismicity. The twentieth century record has been successfully interpreted in terms of a Coulomb failure model, whereby every earthquake concentrates the shear stress at the western tips of the broken segments leading to westward migration of large earthquakes. The August 17 and November 12, 1999, events have loaded the Marmara segment of the fault, mapped since the 1999 earthquakes, and a major, M Đ$ 7.6 event is expected in the next half century with an approximately 50% probability on this segment. Currently, the strain in the Sea of Marmara region is highly asymmetric, with greater strain to the south of the Northern Strand. This is conditioned by the geology, and it is believed that this is generally the case for the entire North Anatolian Fault Zone. What is now needed is a more detailed geological mapping base with detailed paleontology and magnetic stratigraphy in the shear-related basins and more paleomagnetic observations to establish shear-related rotations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120415
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  • 32
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    Digitale Medien
    LAKES BENEATH THE ICE SHEET: The Occurrence, Analysis, and Future Exploration of Lake Vostok and Other Antarctic Subglacial Lakes (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 215-245 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Airborne geophysics has been used to identify more than 100 lakes beneath the ice sheets of Antarctica. The largest, Lake Vostok, is more than 250 km in length and 1 km deep. Subglacial lakes occur because the ice base is kept warm by geothermal heating, and generated meltwater collects in topographic hollows. For lake water to be in equilibrium with the ice sheet, its roof must slope ten times more than the ice sheet surface. This slope causes differential temperatures and melting/freezing rates across the lake ceiling, which excites water circulation. The exploration of subglacial lakes has two goals: to find and understand the life that may inhabit these unique environments and to measure the climate records that occur in sediments on lake floors. The technological developments required for in situ measurements mean, however, that direct studies of subglacial lakes may take several years to happen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122725
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  • 33
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    Digitale Medien
    MOLECULAR APPROACHES TO MARINE MICROBIAL ECOLOGY AND THE MARINE NITROGEN CYCLE (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 301-333 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Microbes are recognized as important components of the Earth system, playing key roles in controlling the composition of the atmosphere and surface waters, forming the basis of the marine food web, and the cycling of chemicals in the ocean. A revolution in microbial ecology has occurred in the past 15Đ??20 years with the advent of rapid methods for discovering and sequencing the genes of uncultivated microbes from natural environments. Initially based on sequences from the 16S rRNA gene, this revolution made it possible to identify microorganisms without first cultivating them, to discover and characterize the immense previously unsuspected diversity of the microbial world, and to reconstruct the evolutionary relationships among microbes. Subsequent focus on functional genes, those that encode enzymes that catalyze biogeochemical transformations, and current work on larger DNA fragments and entire genomes make it possible to link microbial diversity to ecosystem function. These approaches have yielded insights into the regulation of microbial activity and proof of the microbial role in biogeochemical processes previously unknown. Questions raised by the molecular revolution, which are now the focus of microbial ecology research, include the significance of microbial diversity and redundancy to biogeochemical processes and ecosystem function.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122514
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  • 34
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    Digitale Medien
    VOLCANIC SEISMOLOGY (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2005), S. 461-491 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Recent developments in volcanic seismology include new techniques to improve earthquake locations that have changed clouds of earthquakes to lines (faults) for high-frequency events and small volumes for low-frequency (LF) events. Spatial mapping of the b-value shows regions of normal b and high b anomalies at depths of 3Đ??4 and 7Đ??10 km. Increases in b precede some eruptions. LF events and very-long-period (VLP) events have been recorded at many volcanoes, and models are becoming increasingly sophisticated. Deep long-period (LP) events are fairly common, but may represent several processes. Acoustic sensors have greatly improved the study of volcanic explosions. Volcanic tremor is stronger for fissure eruptions, phreatic eruptions, and higher gas contents. Path and site effects can be extreme at volcanoes. Seismicity at volcanoes is triggered by large earthquakes, although mechanisms are still uncertain. A number of volcanoes have significant deformation with very little seismicity. Tomography has benefited from improved techniques and better instrumental arrays.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122459
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  • 35
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    Digitale Medien
    ATMOSPHERIC MOIST CONVECTION (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 605-643 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Various forms of atmospheric moist convection are reviewed through a consideration of three prevalent regimes: stratocumulus; trade-wind; and deep, precipitating, maritime convection. These regimes are chosen because they are structural components of the general circulation of the atmosphere and because they highlight distinguishing features of this polymorphous phenomenon. In particular, the ways in which varied forms of moist convection communicate with remote parts of the flow through mechanisms other than the rearrangement of fluid parcels are emphasized. These include radiative, gravity wave, and/or microphysical (precipitation) processes. For each regime, basic aspects of its phenomenology are presented along with theoretical frameworks that have arisen to help rationalize the phenomenology. Recent developments suggest that the increased capacity for numerical simulation and increasingly refined remote sensing capabilities bodes well for major advances in the coming years.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122658
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  • 36
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    Digitale Medien
    THE NORTH ANATOLIAN FAULT: A NEW LOOK (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 37-112 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The North Anatolian Fault (NAF) is a 1200-km-long dextral strike-slip fault zone that formed by progressive strain localization in a generally westerly widening right-lateral keirogen in northern Turkey mostly along an interface juxtaposing subduction-accretion material to its south and older and stiffer continental basements to its north. The NAF formed approximately 13 to 11 Ma ago in the east and propagated westward. It reached the Sea of Marmara no earlier than 200 ka ago, although shear-related deformation in a broad zone there had already commenced in the late Miocene. The fault zone has a very distinct morphological expression and is seismically active. Since the seventeenth century, it has shown cyclical seismic behavior, with century-long cycles beginning in the east and progressing westward. For earlier times, the record is less clear but does indicate a lively seismicity. The twentieth century record has been successfully interpreted in terms of a Coulomb failure model, whereby every earthquake concentrates the shear stress at the western tips of the broken segments leading to westward migration of large earthquakes. The August 17 and November 12, 1999, events have loaded the Marmara segment of the fault, mapped since the 1999 earthquakes, and a major, MĐ$7.6 event is expected in the next half century with an approximately 50% probability on this segment. Currently, the strain in the Sea of Marmara region is highly asymmetric, with greater strain to the south of the Northern Strand. This is conditioned by the geology, and it is believed that this is generally the case for the entire North Anatolian Fault Zone. What is now needed is a more detailed geological mapping base with detailed paleontology and magnetic stratigraphy in the shear-related basins and more paleomagnetic observations to establish shear-related rotations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120415
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  • 37
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    Digitale Medien
    LAKES BENEATH THE ICE SHEET: The Occurrence, Analysis, and Future Exploration of Lake Vostok and Other Antarctic Subglacial Lakes (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 215-245 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Airborne geophysics has been used to identify more than 100 lakes beneath the ice sheets of Antarctica. The largest, Lake Vostok, is more than 250 km in length and 1 km deep. Subglacial lakes occur because the ice base is kept warm by geothermal heating, and generated meltwater collects in topographic hollows. For lake water to be in equilibrium with the ice sheet, its roof must slope ten times more than the ice sheet surface. This slope causes differential temperatures and melting/freezing rates across the lake ceiling, which excites water circulation. The exploration of subglacial lakes has two goals: to find and understand the life that may inhabit these unique environments and to measure the climate records that occur in sediments on lake floors. The technological developments required for in situ measurements mean, however, that direct studies of subglacial lakes may take several years to happen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122725
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  • 38
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    Digitale Medien
    EARTHQUAKE TRIGGERING BY STATIC, DYNAMIC, AND POSTSEISMIC STRESS TRANSFER (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 335-367 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Earthquake triggering is the process by which stress changes associated with an earthquake can induce or retard seismic activity in the surrounding region or trigger other earthquakes at great distances. Calculations of static Coulomb stress changes associated with earthquake slip have proven to be a powerful tool in explaining many seismic observations, including aftershock distributions, earthquake sequences, and the quiescence of broad, normally active regions following large earthquakes. Delayed earthquake triggering, which can range from seconds to decades, can be explained by a variety of time-dependent stress transfer mechanisms, such as viscous relaxation, poroelastic rebound, or afterslip, or by reductions in fault friction, such as predicted by rate and state constitutive relations. Rapid remote triggering of earthquakes at great distances (from several fault lengths to 1000s of km) is best explained by the passage of transient (dynamic) seismic waves, which either immediately induce Coulomb-type failure or initiate a secondary mechanism that induces delayed triggering. The passage of seismic waves may also play a significant role in the triggering of near-field earthquakes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122505
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    Digitale Medien
    Mathematical Modeling of Whole Landscape Evolution (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 443-459 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The mathematical modeling of landform evolution consists of two components: the processes represented (i.e., considered dominant) in the model and the (typically computer) model representation of these processes. This review discusses the current debates surrounding processes represented in landform evolution. The potential impact on both evolving landforms and computer model structure is discussed. Issues specifically discussed include (a) the fundamental nature of mass conservation and the role of detachment- and transport-limited processes in mass conservation equations, (b) the interaction between detachment- and transport-limitation in channels, (c) the role of hillslope erosion and soil properties and their interaction with channel processes, (d) the interactions with tectonics when applying these models at large scale, (e) depositional structures and implications for paleo-climatic interpretation, (f) engineering applications of these models, and (g) numerical issues in the computer implementations. This review is not a model comparison. However, many applications are at the boundaries of computer capabilities so a comparison of existing models is provided.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122610
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    Digitale Medien
    FEATHERED DINOSAURS (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 277-299 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Recent fossil discoveries from Early Cretaceous rocks of Liaoning Province, China, have provided a wealth of spectacular specimens. Included in these are the remains of several different kinds of small theropod dinosaurs, many of which are extremely closely related to modern birds. Unique preservation conditions allowed soft tissues of some of these specimens to be preserved. Many dinosaur specimens that preserve feathers and other types of integumentary coverings have been recovered. These fossils show a progression of integumentary types from simple fibers to feathers of modern aspect. The distribution of these features on the bodies of these animals is surprising in that some show large tail plumes, whereas others show the presence of wing-like structures on both fore and hind limbs. The phylogenetic distribution of feather types is highly congruent with models of feather evolution developed from developmental biology.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122511
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    Digitale Medien
    EVOLUTION OF FISH-SHAPED REPTILES (REPTILIA: ICHTHYOPTERYGIA) IN THEIR PHYSICAL ENVIRONMENTS AND CONSTRAINTS (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 395-420 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Ichthyosaurs were a group of Mesozoic marine reptiles that evolved fish-shaped body outlines. They are unique in several anatomical characters, including the possession of enormous eyeballs sometimes exceeding 25 cm and an enlarged manus with sometimes up to 20 bones in a single digit, or 10 digits per manus. They are also unique in that their biology has been studied from the perspective of physical constraints, which allowed estimation of such characteristics as optimal cruising speed, visual sensitivity, and even possible basal metabolic rate ranges. These functional inferences, although based on physical principles, obviously contain errors arising from the limitations of fossilized data, but are necessarily stronger than the commonly made inferences based on superficial correlations among quantities without mechanical or optical explanations for why such correlations exist.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122707
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  • 42
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    Digitale Medien
    ARE THE ALPS COLLAPSING? (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 33 (2005), S. 113-132 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Orogenic collapse is a process that transfers gravitational potential energy from regions of high potential energy to regions of lower potential energy. This transfer is classically considered to be accomplished by extension in the orogenic core and by synchronous shortening in foreland regions of the orogen. Not all extensional features in collisional mountain belts need, however, reflect orogenic collapse. Normal faulting, thrust faulting, and strike-slip faulting are all active in different parts of the Alps today and reflect complex local responses to ongoing Europe-Adria convergence. The Western Alps is the only area today where extension and shortening radial to orogen trend occur synchronously and where orogenic collapse may be an important process. Elsewhere in the Alps, normal faults are oriented at a high angle to orogen trend and were primarily active in Oligocene and Miocene time. Most present-day activity in the Central and Eastern Alps is on strike-slip faults that are accommodating lateral extrusion of material rather than orogenic collapse.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.33.092203.122535
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    Digitale Medien
    YUCCA MOUNTAIN: Earth-Science Issues at a Geologic Repository for High-Level Nuclear Waste (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 363-401 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The nation has over 40,000 metric tonnes (MT) of nuclear waste destined for disposal in a geologic repository at Yucca Mountain. In this review, we highlight some of the important geoscience issues associated with the project and place them in the context of the process by which a final decision on Yucca Mountain will be made. The issues include understanding how water could infiltrate the repository, corrode the canisters, dissolve the waste, and transport it to the biosphere during a 10,000-year compliance period in a region, the Basin and Range province, that is known for seismic and volcanic activity. Although the site is considered to be "dry," a considerable amount of water is present as pore waters and as structural water in zeolites. The geochemical environment is oxidizing, and the present repository design will maintain temperatures at greater than 100oC for thousands of years. Geoscientists in this project are challenged to make unprecedented predictions about coupled thermal, hydrologic, mechanical, and geochemical processes governing the future behavior of the repository and to conduct research in a regulatory and legal environment that requires a quantitative analysis of repository performance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.092203.122444
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    Digitale Medien
    INFLUENCE OF THE MENDOCINO TRIPLE JUNCTION ON THE TECTONICS OF COASTAL CALIFORNIA (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 403-433 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The migration of the Mendocino triple junction through central and northern California over the past 25-30 million years has led to a profound change in plate interactions along coastal California. The tectonic consequences of the abrupt change from subduction plate interactions north of the triple junction to the development of the San Andreas transform system south of the triple junction can be seen in the geologic record and geophysical observations. The primary driver of this tectonism is a coupling among the subducting Juan de Fuca (Gorda), North American, and Pacific plates that migrates with the triple junction. This coupling leads to ephemeral thickening of the overlying North American crust, associated uplift and subsequent subsidence, and a distinctive sequence of fault development and volcanism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120252
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    Digitale Medien
    BEDROCK RIVERS AND THE GEOMORPHOLOGY OF ACTIVE OROGENS (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 151-185 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Bedrock rivers set much of the relief structure of active orogens and dictate rates and patterns of denudation. Quantitative understanding of the role of climate-driven denudation in the evolution of unglaciated orogens depends first and foremost on knowledge of fluvial erosion processes and the factors that control incision rate. The results of intense research in the past decade are reviewed here, with the aim of highlighting remaining unknowns and suggesting fruitful avenues for further research. This review considers in turn (a) the occurrence and morphology of bedrock channels and their relation to tectonic setting; (b) the physical processes of fluvial incision into rock; and (c) models of river incision, their implications, and the field and laboratory data needed to test, refine, and extend them.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120356
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    Digitale Medien
    COMPUTER MODELS OF EARLY LAND PLANT EVOLUTION (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 47-66 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Computer models are used to mimic the early evolution of ancient vascular plants (tracheophytes). These models have three components: (a) an N-dimensional domain of all mathematically conceivable ancient morphologies (a morphospace); (b) a numerical assessment of the ability (fitness) of each morphology to intercept light, maintain mechanical stability, conserve water, and produce and disperse spores; and (c) an algorithm that searches the morphospace for successively more fit variants (an adaptive walk). Beginning with the most ancient known plant form, evolution is simulated by locating neighboring morphologies that progressively perform one or more tasks more efficiently. The resulting simulated adaptive walks indicate that early tracheophyte evolution involved optimizing the performance of many tasks simultaneously rather than maximizing the performance of one or only a few tasks individually, and that the requirement for optimization accelerated the tempo of morphological evolution in the Silurian and Devonian.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.092203.122440
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    Digitale Medien
    MULTISPECTRAL AND HYPERSPECTRAL REMOTE SENSING OF ALPINE SNOW PROPERTIES (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 465-494 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Models of processes in the alpine snow cover fundamentally depend on the spatial distribution of the surface energy balance over areas where topographic variability causes huge differences in the incoming solar radiation and in snow depth because of redistribution by wind. At a spatial scale commensurate with that of the terrain, we want to know which areas are covered by snow, and we want to estimate the snow's spectral albedo, along with other properties such as grain size, contaminants, temperature, liquid water content, and depth or water equivalent. From multispectral and hyperspectral remote sensing at wavelengths from 0.4-15 mum, the retrievable properties include snow-covered area, albedo, grain size, liquid water very near the surface, and temperature. Spectral mixture analysis allows the retrieval of the subpixel variability of snow-covered area, along with the snow's albedo. Remaining research challenges include the remote sensing of absorbing impurities; accounting for variability in the bidirectional-reflectance distribution function and the variability of grain size with depth; retrieving snow cover in forested regions; reconciling field measurements of emissivity with snow properties; and adapting the algorithms to frequent, large-scale processing.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120404
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    Digitale Medien
    GENES, DIVERSITY, AND GEOLOGIC PROCESS ON THE PACIFIC COAST (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 601-652 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: We examine the genetics of marine diversification along the West Coast of North America in relation to the Late Neogene geology and climate of the region. Trophically important components of the diverse West Coast fauna, including kelp, alcid birds (e.g., auks, puffins), salmon, rockfish, abalone, and Cancer crabs, appear to have radiated during peaks of upwelling primarily in the Late Miocene and in some cases secondarily in the Pleistocene. Phylogeographic barriers associated with Mio-Pliocene estuaries of the mid-California coast, the Pliocene opening of the Gulf of California, tectonic and eustatic evolution of the California Bight, as well as the influence of Pleistocene and Holocene climate change on genetic structure are assessed in a geologic context. Comparisons to East Coast and western freshwater systems, as well as upwelling systems around the globe, provide perspective for the survey.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.092203.122436
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    Digitale Medien
    ROCK TO SEDIMENT-SLOPE TO SEA WITH 10BE-RATES OF LANDSCAPE CHANGE (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 215-255 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Measurements of cosmogenic nuclides, predominately 10Be, allow new insights into the ways in which and the rates at which sediment is generated, transported, and deposited over timescales ranging from 103 to 106 years. Samples from rock exposures are used to estimate erosion rates at points on the landscape, whereas samples of fluvial sediment provide estimates of basin-scale rates of denudation integrated over 〈1 to 〉104 km2. Nuclide data show that hilltop, bare rock outcrops erode more slowly than basins as a whole, suggesting the potential for relief to increase over time as well-drained outcrops grow higher. More elaborate experiments and interpretive models provide insight into the distribution of hillslope processes, including the bedrock-to-soil conversion rate, which appears to increase under shallow soil cover and then decrease under deeper soils. Changes in average nuclide activity down slopes can be used to estimate grain speed over millennia, suggesting, for example, that sediment on desert piedmonts moves, on average, decimeters to meters per year. In other cases, changes in nuclide activity down river networks or along shorelines can be interpreted with mixing models to indicate sediment sources. Sediment deposition rates in otherwise undateable deposits can now be estimated by analyzing samples collected from depth profiles. Over the past decade, the analysis and interpretation of cosmogenic nuclides has given geomorphologists an unprecedented opportunity to measure rates and infer the distribution of geomorphic processes across Earth's varied landscapes. Long-standing models of landscape change can now be tested quantitatively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120539
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    Digitale Medien
    RIVER AVULSIONS AND THEIR DEPOSITS (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 257-285 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Avulsion is the natural process by which flow diverts out of an established river channel into a new permanent course on the adjacent floodplain. Avulsions are primarily features of aggrading floodplains. Their recurrence interval varies widely among the few modern rivers for which such data exist, ranging from as low as 28 years for the Kosi River (India) to up to 1400 years for the Mississippi. Avulsions cause loss of life, property damage, destabilization of shipping and irrigation channels, and even coastal erosion as sediment is temporarily sequestered on the floodplain. They are also the main process that builds alluvial stratigraphy. Their causes remain relatively unknown, but stability analyses of bifurcating channels suggest that thresholds in the relative energy slope and Shields parameter of the bifurcating channel system are key factors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120201
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    Digitale Medien
    EVOLUTION OF THE NORTH AMERICAN CORDILLERA (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 13-45 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The Cordilleran orogen of western North America is a segment of the Circum-Pacific orogenic belt where subduction of oceanic lithosphere has been underway along a great circle of the globe since breakup of the supercontinent Pangea began in Triassic time. Early stages of Cordilleran evolution involved Neoproterozoic rifting of the supercontinent Rodinia to trigger miogeoclinal sedimentation along a passive continental margin until Late Devonian time, and overthrusting of oceanic allochthons across the miogeoclinal belt from Late Devonian to Early Triassic time. Subsequent evolution of the Cordilleran arc-trench system was punctuated by tectonic accretion of intraoceanic island arcs that further expanded the Cordilleran continental margin during mid-Mesozoic time, and later produced a Cretaceous batholith belt along the Cordilleran trend. Cenozoic interaction with intra-Pacific seafloor spreading systems fostered transform faulting along the Cordilleran continental margin and promoted incipient rupture of continental crust within the adjacent continental block.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120257
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    Digitale Medien
    COMPRESSIONAL STRUCTURES ON MARS (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 435-464 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Wrinkle ridges accommodate very low amounts of shortening strain around immense volcanic constructs and within impact basins on Mars. They originate from stresses distributed uniformly throughout the brittle lithosphere and are consistently located in stratified deposits, including lava flows and sediment. Most recent models interpret wrinkle ridges as the surface manifestation of folding above underlying blind thrusts that accommodate similarly low strain and likely penetrate tens of kilometers into the brittle crust. Alternative models suggest shortening accommodated by some wrinkle ridges is confined to only the upper few kilometers of the crust. The interpretation of the geometry of blind thrusts on Mars appears to be quite varied and remains controversial, although some models suggest they may ultimately flatten into the brittle-ductile transition in the middle to lower crust. Small-scale crenulations superposed on ridges are interpreted as produced by high-level back thrusts nucleating at a weak layer in the upper crust, or by flexural slip faults that facilitate bending of layered materials. Wrinkle ridges are related to their structural cousins, lobate scarps that accommodate shortening in older Noachian cratered highlands as surface fault ruptures. Wrinkle ridges thus form when displacement across upwardly propagating blind thrusts is consumed by folding of layered material near the surface. Conversely, lobate scarps are formed by blind thrusts that are not impeded by folding of overlying layered deposits. Broad, low-amplitude arches associated with ridges on the Tharsis rise also accommodate shortening, but their relationship to adjacent or superposed ridges remains enigmatic. The evenly spaced nature of wrinkle ridges that appears to vary systematically between the ridged plains and northern lowlands may be related to the depth of the brittle-ductile transition, which is respectively located in the middle crust and upper mantle in these regions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120553
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    Digitale Medien
    GEOMORPHOLOGY: A Sliver Off the Corpus of Science (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 1-12 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.032803.153614
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    Digitale Medien
    TRANSITION METAL SULFIDES AND THE ORIGINS OF METABOLISM (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 569-599 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The history of the theory and experimental evidence that the natural catalytic and reactive qualities of transition metal sulfides are linked to primitive metabolism is reviewed. In the late 1980s, a hypothesis arose that proposed that transition metal sulfides (in particular pyrrhotite and pyrite) might play a significant role promoting abiotic organic chemistry. As an outgrowth of this hypothesis, elaborate theories were presented, including proposals for earliest life being structurally distinct from extant prokaryotic life. During the 1990s and into the twenty-first century, experimental evidence has emerged that supports certain aspects of these theories; in other cases, the experiments reveal chemistry that diverges significantly from that which was proposed theoretically. In either case, however, there is clear evidence that transition metal sulfide minerals exhibit catalytic qualities for the promotion of reactions that have obvious metabolic utility and, therefore, could have provided the primitive Earth with valuable biochemical intermediates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120225
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    Digitale Medien
    LATE CENOZOIC INCREASE IN ACCUMULATION RATES OF TERRESTRIAL SEDIMENT: How Might Climate Change Have Affected Erosion Rates? (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 67-89 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Accumulation rates of terrestrial sediment have increased in the past few million years both on and adjacent to continents, although not everywhere. Apparently, erosion has increased in elevated terrain regardless of when last tectonically active or what the present-day climate. In many regions, sediment coarsened abruptly in late Pliocene time. Sparser data suggest increased sedimentation rates at ~15 Ma, approximately when oxygen isotopes in benthic foraminifera imply high-latitude cooling. If climate change effected accelerated erosion, understanding how it did so remains the challenge. Some obvious candidates, such as lowered sea level leading to erosion of continental shelves or increased glaciation, account for increased sedimentation in some, but not all, areas. Perhaps stable climates that varied slowly allowed geomorphic processes to maintain a state of equilibrium with little erosion until ~3-4 Ma, when large oscillations in climate with periods of 20,000-40,000 years developed and denied the landscape the chance to reach equilibrium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.091003.143456
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    Digitale Medien
    SPACE WEATHERING OF ASTEROID SURFACES (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 539-567 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Visible and near-infrared spectra of reflected sunlight from asteroid surfaces exhibit features that hold the promise for identifying surface mineralogy. However, the very surfaces that are observed by remote-sensing are also subject to impingement by micrometeoroids and solar wind particles, which are believed to play the dominant role in space weathering, which is the time-dependent modification of an asteroid's reflectance spectrum. Such space weathering has confused the interpretations of telescopic spectra of asteroids, especially concerning the possible association of common ordinary chondritic meteorites with so-called S-type asteroids. Recent spacecraft studies of asteroids (especially of Eros by NEAR-Shoemaker) have documented aspects of space weathering processes, but we still do not understand the physics of space weathering well enough to confidently assay mineralogy of diverse asteroids by remote-sensing. A review of the intellectual history of this topic reveals the complexity of interdisciplinary research on far-away astronomical bodies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120453
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    Digitale Medien
    BIOGENIC MANGANESE OXIDES: Properties and Mechanisms of Formation (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 287-328 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Manganese(IV) oxides produced through microbial activity, i.e., biogenic Mn oxides or Mn biooxides, are believed to be the most abundant and highly reactive Mn oxide phases in the environment. They mediate redox reactions with organic and inorganic compounds and sequester a variety of metals. The major pathway for bacterial Mn(II) oxidation is enzymatic, and although bacteria that oxidize Mn(II) are phylogenetically diverse, they require a multicopper oxidase-like enzyme to oxidize Mn(II). The oxidation of Mn(II) to Mn(IV) occurs via a soluble or enzyme-complexed Mn(III) intermediate. The primary Mn(IV) biooxide formed is a phyllomanganate most similar to delta-MnO2 or acid birnessite. Metal sequestration by the Mn biooxides occurs predominantly at vacant layer octahedral sites.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120213
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    Preface by Raymond Jeanloz (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004) 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.ea.32.033004.100001
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    GLOBAL GLACIAL ISOSTASY AND THE SURFACE OF THE ICE-AGE EARTH: The ICE-5G (VM2) Model and GRACE (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 111-149 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The 100 kyr quasiperiodic variation of continental ice cover, which has been a persistent feature of climate system evolution throughout the most recent 900 kyr of Earth history, has occurred as a consequence of changes in the seasonal insolation regime forced by the influence of gravitational n-body effects in the Solar System on the geometry of Earth's orbit around the Sun. The impacts of the changing surface ice load upon both Earth's shape and gravitational field, as well as upon sea-level history, have come to be measurable using a variety of geological and geophysical techniques. These observations are invertible to obtain useful information on both the internal viscoelastic structure of the solid Earth and on the detailed spatiotemporal characteristics of glaciation history. This review focuses upon the most recent advances that have been achieved in each of these areas, advances that have proven to be central to the construction of the refined model of the global process of glacial isostatic adjustment, denoted ICE-5G (VM2). A significant test of this new global model will be provided by the global measurement of the time dependence of the gravity field of the planet that will be delivered by the GRACE satellite system that is now in space.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.082503.144359
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    RECENT DEVELOPMENTS IN THE STUDY OF OCEAN TURBULENCE (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 91-109 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: This review describes the changes in the understanding of turbulence and mixing in the upper layers of the ocean, the abyssal ocean, and in continental shelf seas that have come in the past 25 years, largely through advances in instruments and methodology.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.071603.152635
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    Preface by Raymond Jeanloz (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004) 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.ea.32.033004.100001
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    MODERN ANALOGS IN QUATERNARY PALEOECOLOGY: Here Today, Gone Yesterday, Gone Tomorrow? (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 495-537 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Modern analog analysis, the comparison of Quaternary fossil pollen assemblages with modern assemblages, has long been a mainstay of paleoecological and paleoclimatic inference. The logic of analogical inference involves a comparative element (comparison of modern and fossil assemblages to select matches and assess goodness of fit) and a causal element (assumption that the relationships between modern vegetation and derivative pollen assemblages are matched by those between ancient vegetation and fossil pollen assemblages). An array of numerical and statistical tools have been developed to ensure objective, consistent, and quantitative assessments of similarity between pollen assemblages. Divergent or convergent relationships between vegetation and pollen assemblages can arise from a variety of sources, composing a potential source of error in analog analysis, but such errors can be anticipated and minimized. Pollen assemblages lacking modern analogs are well documented for the late-glacial period (17,000-10,000 years BP) in eastern North America and other regions. Simulated climates for this period also lacked modern analogs owing to increased seasonality of insolation, lowered CO2, and persistent ice sheets. Most pollen assemblages from the last glacial maximum (23,000-20,000 years BP) in eastern North America have modern analogs, but macrofossil and other evidence suggest that the vegetation may have lacked modern analogs, owing to unique climate realizations and perhaps direct effects of lowered CO2. Better understanding of the nature of past no-analog vegetation, and the underlying causes, will address important issues in ecology and evolutionary biology and help anticipate biotic responses to the no-analog greenhouse world of the near-future.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120435
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    SPHERULE LAYERS-RECORDS OF ANCIENT IMPACTS (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 329-361 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: A large extraterrestrial object striking Earth at cosmic velocity melts and vaporizes silicate materials, which can condense into highly spheroidal, sand-size particles that get deposited hundreds to thousands of kilometers from the point of impact. These particles, known as impact spherules, have been detected in great abundance in a relatively small number of thin, discrete layers ranging in age from less than a million years to 3.47 billion years. Unaltered impact spherules consist entirely of glass (microtektites) or a combination of glass and crystals grown in flight (microkrystites). Impact spherule layers form very rapidly and can be very extensive, even global in extent [e.g., the Cretaceous-Tertiary (K/T) boundary layer], so they form excellent time-stratigraphic markers. Because they are always found in a stratigraphic context, spherule layers are probably superior to terrestrial craters and related structures for assessing the environmental and biotic effects of large impacts. A record of impacts whose craters have since been obliterated, most notably those in pre-Mesozoic oceanic crust, could survive in the form of spherule layers. Secular changes in surface environments and/or the nature of the impactors striking Earth through its history could also be reflected in differences in spherules and spherule layers as a function of geologic age. In this paper, we briefly review what spherules and spherule layers are and the processes that create them, then speculate about what might be learned through wider identification of and more extensive study of impact spherule layers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120458
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    QUANTITATIVE BIOSTRATIGRAPHY-ACHIEVING FINER RESOLUTION IN GLOBAL CORRELATION (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 187-213 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: The fossil record preserves a wide range of events that might be used to build timescales and correlate strata from place to place. The events include the originations and extinctions of species, the occurrence of distinctive faunal assemblages, magnetic field reversals, changes in ocean chemistry, and volcanic ash falls. The fundamental task is to determine the global sequence of all these events. Modern computer algorithms can build high-resolution timescales by sequencing and calibrating thousands of such events from hundreds of localities. Each successful sequencing algorithm can be understood in terms of a simple two-dimensional visual device. Graphic correlation, permutable sequences, permutable matrices, and slotting devices are each suited to a different data problem, such as contradictory evidence of sequence, a lack of information about sequence, or uncertain correspondence of events. Algorithms based upon permutable sequences and evolutionary programming heuristics have the flexibility to optimize sequences with a wide variety of event types and data problems; they are slower than the more narrowly tailored methods. All methods will be challenged to keep pace with the amount of biostratigraphic information that is accumulating in the latest generation of shared databases. Currently, it is possible to sequence sufficiently large numbers of events to imagine a potential resolution of 10,000 to 50,000 years over time spans on the order of 50 to 100 million years. The actual resolving power is less because the solutions to these sequencing problems are not unique. Multiple equally good solutions typically emerge and, to extract a consensus sequence with which all solutions agree, some runs of events must be collapsed into unresolvable clusters. Nevertheless, quantitative methods have been shown to improve resolution up to tenfold over traditional methods that discard many potentially useful events.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.32.101802.120428
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    HOLOCENE EARTHQUAKE RECORDS FROM THE CASCADIA SUBDUCTION ZONE AND NORTHERN SAN ANDREAS FAULT BASED ON PRECISE DATING OF OFFSHORE TURBIDITES (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 555-577 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract We present preliminary evidence for a ~10,000-year earthquake record from two major fault systems based on sediment cores collected along the continental margins of western North America. New stratigraphic evidence from Cascadia demonstrates that 13 earthquakes ruptured the entire margin from Vancouver Island to at least the California border since the eruption of the Mazama ash 7700 years ago. The 13 events above this prominent stratigraphic marker have an average repeat time of 600 years, and the youngest event ~300 years ago coincides with the coastal record. We also extend the record of past earthquakes to the base of the Holocene (at least 9800 years ago), during which 18 events correlate along the same region. The sequence of Holocene events in Cascadia appears to contain a repeating pattern of events, a tantalizing first look at what may be the long-term behavior of a major fault system. The northern California margin cores show a cyclic record of turbidite beds that may represent Holocene earthquakes on the northern segment of the San Andreas Fault. Preliminary results are in reasonably good agreement with onshore paleoseismic data that indicate an age for the penultimate event in the mid-1600s at several sites and the most likely age for the third event of ~AD 1300.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141246
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    RHEOLOGY OF GRANITIC MAGMAS DURING ASCENT AND EMPLACEMENT (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 399-427 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Considerable progress has been made over the past decade in understanding the static rheological properties of granitic magmas in the continental crust. Changes in H2O content, CO2 content, and oxidation state of the interstitial melt phase have been identified as important compositional factors governing the rheodynamic behavior of the solid/fluid mixture. Although the strengths of granitic magmas over the crystallization interval are still poorly constrained, theoretical investigations suggest that during magma ascent, yield strengths of the order of 9 kPa are required to completely retard the upward flow in meter-wide conduits. In low Bagnold number magma suspensions with moderate crystal contents (solidosities 0.1 〈=phi〈= 0.3), viscous fluctuations may lead to flow differentiation by shear-enhanced diffusion. AMS and microstructural studies support the idea that granite plutons are intruded as crystal-poor liquids (phi〈= 50%), with fabric and foliation development restricted to the final stages of emplacement. If so, then these fabrics contain no information on the ascent (vertical transport) history of the magma. Deformation of a magmatic mush during pluton emplacement can enhance significantly the pressure gradient in the melt, resulting in a range of local macroscopic flow structures, including layering, crystal alignment, and other mechanical instabilities such as shear zones. As the suspension viscosity varies with stress rate, it is not clear how the timing of proposed rheological transitions formulated from simple equations for static magma suspensions applies to mixtures undergoing shear. New theories of magmas as multiphase flows are required if the full complexity of granitic magma rheology is to be resolved.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141352
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    IS EL NINO SPORADIC OR CYCLIC? (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 579-594 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Is El Nino one phase of a continual, self-sustaining natural mode of the coupled ocean-atmosphere that has La Nina as the complementary phase? Or is El Nino a temporary departure from "normal" conditions "triggered" by a random disturbance such as a burst of westerly winds? A growing body of evidence-stability analyses, studies of the energetics, simulations that reproduce the statistics of sea surface temperature variations in the eastern equatorial Pacific-indicates that reality corresponds to a compromise between these two possibilities: The observed Southern Oscillation between El Nino and La Nina corresponds to a weakly damped mode that is sustained by random disturbances. This means that the predictability of El Nino is limited by the continual presence of "noise" so that forecasts should be probabilistic. The Southern Oscillation is also subject to decadal modulations. How it will be influenced by global warming is a matter of considerable uncertainty.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141255
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    THE ROLE OF DECAY AND MINERALIZATION IN THE PRESERVATION OF SOFT-BODIED FOSSILS (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 275-301 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Fossil deposits that preserve soft-bodied organisms provide critical evidence of the history of life. Usually, only more decay resistant materials, e.g., cuticles, survive as organic remains as a result of selective preservation and subsequent diagenesis to more resistant biopolymers. Permineralization, the permeation of tissues by mineralizing fluids, may preserve remarkable detail, particularly of plants. However, evidence of more labile tissues, e.g., muscle, normally requires the replication of their morphology by rapid in situ growth of minerals, i.e., authigenic mineralization. This process relies on the steep geochemical gradients generated by decay microbes. The minerals involved, and the level of detail preserved (which may be subcellular), depend on a number of factors, including the nature of microbial activity and amount of decay, availability of ions, and the type of organism that is fossilized. Understanding these controls is essential to determining the conditions that favor exceptional preservation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.144746
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    PRODUCTION, ISOTOPIC COMPOSITION, AND ATMOSPHERIC FATE OF BIOLOGICALLY PRODUCED NITROUS OXIDE (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 329-356 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The anthropogenic production of greenhouse gases and their consequent effects on global climate have garnered international attention for years. A remaining challenge facing scientists is to unambiguously quantify both sources and sinks of targeted gases. Microbiological metabolism accounts for the largest source of nitrous oxide (N2O), mostly due to global conversion of land for agriculture and massive usage of nitrogen-based fertilizers. A most powerful method for characterizing the sources of N2O lies in its multi-isotope signature. This review summarizes mechanisms that lead to biological N2O production and how discriminate placement of 15N into molecules of N2O occurs. Through direct measurements and atmospheric modeling, we can now place a constraint on the isotopic composition of biological sources of N2O and trace its fate in the atmosphere. This powerful interdisciplinary combination of biology and atmospheric chemistry is rapidly advancing the closure of the global N2O budget.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.110502.080901
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    CATASTROPHIC FLOODING OF THE BLACK SEA (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 525-554 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Decades of seabed mapping, reflection profiling, and seabed sampling reveal that throughout the past two million years the Black Sea was predominantly a freshwater lake interrupted only briefly by saltwater invasions coincident with global sea level highstand. When the exterior ocean lay below the relatively shallow sill of the Bosporus outlet, the Black Sea operated in two modes. As in the neighboring Caspian Sea, a cold climate mode corresponded with an expanded lake and a warm climate mode with a shrunken lake. Thus, during much of the cold glacial Quaternary, the expanded Black Sea's lake spilled into to the Marmara Sea and from there to the Mediterranean. However, in the warm climate mode, after receiving a vast volume of ice sheet meltwater, the shoreline of the shrinking lake contracted to the outer shelf and on a few occasions even beyond the shelf edge. If the confluence of a falling interior lake and a rising global ocean persisted to the moment when the rising ocean penetrated across the dividing sill, it would set the stage for catastrophic flooding. Although recently challenged, the flood hypothesis for the connecting event best fits the full set of observations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141249
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    METAL-SILICATE PARTITIONING OF SIDEROPHILE ELEMENTS AND CORE FORMATION IN THE EARLY EARTH* (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 135-174 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Accretion models for the Earth and terrestrial planets are based on the distribution of siderophile (iron-loving) elements between metal and silicate. Extensive experimental studies of the partitioning of these elements between metallic liquid and silicate melt have led to a better understanding and a more sophisticated application to planetary problems. Siderophile element metal/silicate partition coefficients are a function of temperature, pressure, oxygen fugacity, and metal and silicate composition. Quantification of these effects for a limited subset of siderophile elements has led to the idea that early Earth had a 700-km or deeper magma ocean. This new understanding of siderophile element partitioning has also led to applications to the kinetics of metal-silicate equilibrium, links to the timing of core formation, and a better understanding of core formation and metal-silicate equilibrium in the Moon and Mars. Key issues for future consideration include the role of water in early Earth, consideration of the core as a reservoir for noble gases and/or traditionally lithophile elements, siderophile element concentrations in the deep mantle, oxygen fugacity at high pressures, and further evaluation of the need for a late accretional veneer. The strongest approach to improving accretion models for the terrestrial planets is one that combines geochemistry, geophysics, and planetary dynamics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.145451
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    GLOBAL MANTLE TOMOGRAPHY: Progress Status in the Past 10 Years (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 303-328 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract We review the present status of global mantle tomography and discuss two main classes of models that have been developed in the past 10 years: P velocity models based on large datasets of travel times from the International Seismological Centre bulletins, often referred to as "high resolution" models, and S velocity models based on a combination of surface wave and hand picked body wave travel times, or waveforms, referred to as "long wavelength" models. We discuss their respective strengths and weaknesses, as well as progress in the resolution of other physical parameters, such as anisotropy, anelasticity, density, and bulk sound velocity using tomographic approaches. We present the view that future improvements in global seismic tomography require the utilization of the rich information contained in complete broadband seismic waveforms. This is presently within our reach owing to theoretical progress as well as the increase in computational power in recent years.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.091602.113555
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    THE INDIAN MONSOON AND ITS VARIABILITY (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 429-467 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract For over 300 years, the monsoon has been viewed as a gigantic land-sea breeze. It is shown in this paper that satellite and conventional observations support an alternative hypothesis, which considers the monsoon as a manifestation of seasonal migration of the intertropical convergence zone (ITCZ). With the focus on the Indian monsoon, the mean seasonal pattern is described, and why it is difficult to simulate it is discussed. Some facets of the intraseasonal variation, such as active-weak cycles; break monsoon; and a special feature of intraseasonal variation over the region, namely, poleward propagations of the ITCZ at intervals of 2-6 weeks, are considered. Vertical moist stability is shown to be a key parameter in the variation of monthly convection over ocean and land as well as poleward propagations. Special features of the Bay of Bengal and the monsoon brought out by observations during a national observational experiment in 1999 are briefly described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141251
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    PHANEROZOIC ATMOSPHERIC OXYGEN (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 105-134 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Theoretical calculations, based on both the chemical and isotopic composition of sedimentary rocks, indicate that atmospheric O2 has varied appreciably over Phanerozoic time, with a notable excursion during the Permo-Carboniferous reaching levels as high as 35% O2. This agrees with measurements of the carbon isotopic composition of fossil plants together with experiments and calculations on the effect of O2 on photosynthetic carbon isotope fractionation. The principal cause of the excursion was the rise of large vascular land plants and the consequent increased global burial of organic matter. Higher levels of O2 are consistent with the presence of Permo-Carboniferous giant insects, and preliminary experiments indicate that insect body size can increase with elevated O2. Higher O2 also may have caused more extensive, possibly catastrophic, wildfires. To check this, realistic burning experiments are needed to examine the effects of elevated O2 on fire behavior.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141329
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    THE EFFECTS OF BIOTURBATION ON SOIL PROCESSES AND SEDIMENT TRANSPORT (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 249-273 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Plants and animals exploit the soil for food and shelter and, in the process, affect it in many different ways. For example, uprooted trees may break up bedrock, transport soil downslope, increase the heterogeneity of soil respiration rates, and inhibit soil horizonation. In this contribution, we review previously published papers that provide insights into the process of bioturbation. We focus particularly on studies that allow us to place bioturbation within a quantitative framework that links the form of hillslopes with the processes of sediment transport and soil production. Using geometrical relationships and data from others' work, we derive simple sediment flux equations for tree throw and root growth and decay.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141314
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    ISOTOPIC ADVENTURES-Geological, Planetological, and Cosmic (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 1-74 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141409
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    TROPICAL CYCLONES (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 75-104 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Tropical cyclones encompass virtually every subdiscipline of geophysical fluid dynamics, including cumulus convection, boundary layers, thermodynamic cycles, surface wave dynamics, upper ocean wind-driven circulations, barotropic instability, Rossby waves, and air-sea interaction. After briefly reviewing what is known about the structure, behavior, and climatology of these fascinating storms, the author provides an overview of their physics, focusing on the unique and poorly understood nature of the air-sea interface, and discusses several of the most interesting avenues of ongoing research.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141259
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    MADAGASCAR: Heads It's a Continent, Tails It's an Island (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 213-248 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Neither geologists nor biologists have a definition that is capable of classifying Madagascar unambiguously as an island or a continent; nor can they incorporate Malagasy natural history into a single model rooted in Africa or Asia. Madagascar is a microcosm of the larger continents, with a rock record that spans more than 3000 million years (Ma), during which it has been united episodically with, and divorced from, Asian and African connections. This is reflected in its Precambrian history of deep crustal tectonics and a Phanerozoic history of biodiversity that fluctuated between cosmopolitanism and parochialism. Both vicariance and dispersal events over the past 90 Ma have blended a unique endemism on Madagascar, now in decline following rapid extinctions that started about 2000 years ago.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141337
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    RECOGNIZING MANTLE PLUMES IN THE GEOLOGICAL RECORD (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 469-523 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Mantle plumes are recognized by domal uplift, triple junction rifting, and especially the presence of a large igneous province (LIP), dominated in the Phanerozoic by flood basalts, and in the Proterozoic by the exposed plumbing system of dykes, sills, and layered intrusions. In the Archean, greenstone belts that contain komatiites have been linked to plumes. In addition, some carbonatites and kimberlites may originate from plumes that have stalled beneath thick lithosphere. Geochemistry and isotopes can be used to test and characterize the plume origin of LIPs. Seismic tomography and geochemistry of crustal and subcrustal xenoliths in kimberlites can identify fossil plumes. More speculatively, plumes (or clusters of plumes) have been linked with variation in the isotopic composition of marine carbonates, sea-level rise, iron formations, anoxia events, extinctions, continental breakup, juvenile crust production, magnetic superchrons, and meteorite impacts. The central region of a plume is located using the focus of a radiating dyke swarm, the distribution of komatiites and picrites, etc. The outer boundary of a plume head circumscribes the main flood basalt distribution and approximately coincides with the edge of domal uplift that causes shoaling and offlap in regional sedimentation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.145500
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    VOLCANIC ACTIVITY ON IO DURING THE GALILEO ERA (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 175-211 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Galileo's explorations have revealed a remarkable variety of eruptive styles among Io's diverse volcanoes. Activity at hundreds of volcanic centers ranges from dormant through sporadic to continuous over the 20-year period of spacecraft observation. High temperature volcanism is common on Io, suggesting that the lavas are made up of mafic to ultramafic silicates rather than sulfur compounds. Io's largest plumes are driven by SO2 and sulfur-rich gasses vented from the silicate interior that produce prominent red pyroclastic deposits. Red deposits flag the source regions of many other ongoing or very recent eruptions. Smaller plumes are produced near the margins of active lava flows by explosive volatilization of the underlying or surrounding SO2. These plumes produce SO2 snowflakes that mantle existing topography. Io's volcanism drives significant variations in the atmosphere and plasma torus, yet most of the heat loss occurs through lava flows and by the quiet overturning of lava lakes without large-scale explosive activity. Although only a handful of Io's volcanoes have been directly observed to produce explosive eruptions, volcanic resurfacing is efficient enough to erase even small craters from Io's youthful surface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.145428
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    PHYLOGENETIC APPROACHES TOWARD CROCODYLIAN HISTORY (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 31 (2003), S. 357-397 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract A review of crocodylian phylogeny reveals a more complex history than might have been anticipated from a direct reading of the fossil record without consideration of phylogenetic relationships. The three main extant crocodylian lineages-Gavialoidea, Alligatoroidea, Crocodyloidea-are known from fossils in the Late Cretaceous, and the group is found nearly worldwide during the Cenozoic. Some groups have distributions that are best explained by the crossing of marine barriers during the Tertiary. Early Tertiary crocodylian faunas are phylogenetically composite, and clades tend to be morphologically uniform and geographically widespread. Later in the Tertiary, Old World crocodylian faunas are more endemic. Crocodylian phylogeneticists face numerous challenges, the most important being the phylogenetic relationships and time of divergence of the two living gharials (Gavialis gangeticus and Tomistoma schlegelii), the relationships among living true crocodiles (Crocodylus), and the relationships among caimans.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.31.100901.141308
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    DATING THE TIME OF ORIGIN OF MAJOR CLADES: Molecular Clocks and the Fossil Record (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 65-88 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Molecular and paleontological data provide independent means of estimating when groups of organisms evolved in the geological past, but neither approach can be considered straightforward. The single most fundamental obstacle to developing an accurate estimate of times of origination from gene sequence data is variation in rates of molecular evolution, both through time and among lineages. Although various techniques have been proposed to circumvent this problem, none unambiguously allow the components of time and rate to be separated. Furthermore, problems of establishing accurate calibration points, correctly rooted phylogenies, and accurate estimates of branch length remain formidable. Conversely, paleontological dates fix only the latest possible time of divergence, and so probabilistic methods are required to set a lower boundary on origination dates. Realistic confidence intervals that take preservational biases into account are only just becoming available. Although molecular and paleontological approaches to dating often agree reasonably well, there are two notable areas of disagreement; when mammal and bird orders originated and when the major phyla originated. The discrepancy in dating bird/mammal ordinal origins probably reflects a global rock-record bias. Paleontological sampling in the Late Cretaceous is still too restricted geographically to draw any firm conclusions about the existence of a pre-Tertiary record for modern orders of bird or mammal from anywhere other than North America. Dating the time of origin of phyla is more complicated, and is confounded by both preservational biases and problems of molecular clock estimation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.140057
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    PETROLOGY OF SUBDUCTED SLABS (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 207-235 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The subducted lithosphere is composed of a complex pattern of chemical systems that undergo continuous and discontinuous phase transformation, through pressure and temperature variations. Volatile recycling plays a major geodynamic role in triggering mass transfer, melting, and volcanism. Although buoyancy forces are controlled by modal amounts of the most abundant phases, usually volatile-free, petrogenesis and chemical differentiation are controlled by the occurrence of minor phases, most of them volatile-bearing. Devolatilization of the subducted lithosphere is a continuous process distributed over more than 300 km of the slab-mantle interface. Melting of the subducted crust, if any, along sufficiently hot P-T paths, is governed by fluid-absent reactions, even though the difference between fluid and melt vanishes at pressures above the second critical end point. The density distribution at a depth of 660 km suggests episodic penetration in space and time of subducted slabs into the lower mantle and sinking down to the D" region at the core-mantle boundary.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.140550
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    PLUTO AND CHARON: Formation, Seasons, Composition (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 307-345 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Pluto and Charon, once thought to be a singular system in an odd orbit at the edge of the solar system, are now known as members of a vast population of icy bodies beyond Neptune. Models for the occurrence of the odd orbit and formation of these bodies in the context of the total population are reviewed. Pluto's orbital characteristics, coupled with the existence of volatiles on the surface, suggest that large-scale seasonal change should occur on the surface. Models of seasonal variability are discussed, past and current observations are examined for evidence of variability, and a straw-man model of seasonal changes is proposed. Finally, recent observations of the surface composition of Charon are discussed and compared with observations of other similarly sized icy bodies in the outer Solar System.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.090401.095213
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    EARTHQUAKE PREDICTION: State-of-the-Art and Emerging Possibilities (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 1-33 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.100301.083856
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    IMPLICATIONS OF EXTRASOLAR PLANETS FOR UNDERSTANDING PLANET FORMATION (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 113-148 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The observed properties of extrasolar planets and planetary systems are reviewed, including discussion of the mass, period, and eccentricity distributions; the presence of multiple systems; and the properties of the host stars. In all cases, the data refer to systems with ages in the Ga range. Some of the properties primarily reflect the formation mechanism, while others are determined by postformation dynamical evolutionary processes. The problem addressed here is the extraction of information relevant to the identification of the formation mechanism. The presumed formation sites, namely disks around young stars, therefore, must provide clues at times much closer to the actual formation time. The properties of such disks are briefly reviewed. The amount of material and its distribution in the disks provide a framework for the development of a model for planet formation. The strengths of, as well as the problems with, the two major planet formation mechanisms-gravitational instability and core accretion-gas capture-are then described. It is concluded that most of the known planetary systems are best explained by the accretion process. The timescales for the persistence of disks and for the formation time by this process are similar, and the mass range of the observed planets, up to approximately 10 Jupiter masses, is naturally explained. The mass range of 5-15 Jupiter masses probably represents an overlapping transition region, with planetary formation processes dominating below that range and star formation processes dominating above it.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.140357
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    GEODYNAMO SIMULATIONS-HOW REALISTIC ARE THEY? (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 237-257 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The past seven years have seen significant advances in computational simulations of convection and magnetic field generation in the Earth's core. Although dynamically self-consistent models of the geodynamo have simulated magnetic fields that appear in some ways quite similar to the geomagnetic field, none are able to run in an Earth-like parameter regime because of the considerable spatial resolution that is required. Here we discuss some of the subtle compromises that have been made in current models and propose a grand challenge for the future, requiring significant improvements in numerical methods and spatial resolution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.140817
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    GEOLOGIC STRUCTURE OF THE UPPERMOST OCEANIC CRUST CREATED AT FAST- TO INTERMEDIATE-RATE SPREADING CENTERS (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 347-384 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Geological investigations of major fault scarps ("tectonic windows") and DSDP/ODP Drill Holes provide direct views of the uppermost oceanic crust generated at fast- to intermediate-rate spreading centers. These areas reveal a consistent upper crustal structural geometry with basaltic lava flows defining a pattern of downward increasing ("inward") dip toward the spreading center at which they formed and dikes in the lavas and underlying sheeted dike complex showing a similar degree of "outward" dip. Widespread fracturing, faulting, and hydrothermal metamorphism accompanied magmatic construction. These geological relationships can be interpreted in terms of dramatic, asymmetrical, subaxial subsidence of upper crustal rock units that diminishes across the very narrow (few kilometers wide) zone of lava accumulation and dike intrusion at the ridge axis. This type of crustal structure is in accord with some existing models of spreading but augments these idealized views with more realistic geological complexity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.141132
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    MANTLE MIXING: The Generation, Preservation, and Destruction of Chemical Heterogeneity (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 493-525 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Observations of the geochemical diversity of mid-oceanic ridge and ocean-island basalts have traditionally been attributed to the existence of large-scale mantle heterogeneity. In particular, the layered convection model has provided an important conceptual basis for discussing the chemical evolution of the Earth. In this model, a long-term boundary is assumed between a well-mixed and depleted upper mantle and a heterogeneous and more primitive lower mantle. The existence of high 3He/4He in ocean-island sources has been used to argue for the preservation of a primitive component in the deep mantle. Nevertheless, a primitive deep layer is difficult to reconcile with the abundant lithophile isotopic evidence for recycling of oceanic crust and the lack of preservation of primitive mantle. In addition, the widespread acceptance of geophysical evidence for whole mantle flow has made straightforward application of the layered convection model problematic. Model calculations show that whole mantle convection with present day heat flow and surface velocities is sufficiently vigorous to mix large-scale heterogeneity to an extent that is incompatible with the geochemical observations. Several concepts have been proposed in recent years to resolve the apparent conflicts between the various observational constraints and theoretical interpretations. The suggestions include the presence of deeper layering, preservation of highly viscous blobs, core mantle interaction, and strong temporal variations in mantle dynamics. Although these models generally appear to solve parts of the puzzle, at present no single model is able to account for all of the major observations. The reconciliation of conflicting evidence awaits improvements in observational and experimental techniques integrated with better model testing of hypotheses for the generation and destruction of mantle heterogeneity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.141236
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    MODERN INTEGRATIONS OF SOLAR SYSTEM DYNAMICS (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 89-112 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Until the early 1990s, numerical simulations of Solar System dynamics were done using accurate but slow integrators. The typical timescales were on the order of a million years, apart from exceptions achieved by considering averaged equations or using specifically designed supercomputers. In the last decade, new numerical integration methods for Solar System dynamics have been introduced. The mixed variable symplectic method (Wisdom & Holman 1991) has permitted the study, in the absence of close encounters, of the evolution of planets and small bodies on timescales comparable to the age of the Solar System. The regularized mixed variable scheme (Levison & Duncan 1994) has allowed the compilation of statistics on the evolution of thousands of near-Earth asteroids and comets, from their source regions to their dynamical elimination. The Symba and the Mercury codes (Duncan et al. 1998, Chambers 1999), which treat close encounters between massive bodies in a symplectic way, have permitted the simulations of planetary accretion and of the early phase of the highly chaotic evolution of the Solar System. This paper reviews the most exciting results obtained with these new integrators. Emphasis is given to the conceptual steps that these works represent in our understanding of Solar System dynamics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.140243
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    STREAMFLOW NECESSARY FOR ENVIRONMENTAL MAINTENANCE (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 181-206 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract In the last decades, insights from the fields of ecology, geomorphology, and hydrology have been applied to the question of the streamflows necessary for environmental maintenance. For instance, determining the streamflow needed for spawning by salmon or trout requires ascertaining how much water, for how long, and at what time it will be needed? And what flows are necessary for the sustenance of streamside vegetation? Answers to these and similar questions have been sought to minimize environmental degradation in the development or relicensing of water projects, in restoring riverine ecosystems, and in balancing multiple uses for limited water resources. In this contribution, the varieties of environmental maintenance flows applied to rivers are described, as are their fundamental principles. These environmental maintenance flows include flows to maintain aesthetics and recreation, streambed sediment size and its mobility, the channel, its features and continuity, and the floodplain, its wetness regime, and riparian vegetation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.083001.161748
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    PRELUDE TO THE CAMBRIAN EXPLOSION (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 285-306 
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    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The Prelude began with the origin of Metazoa, perhaps between 720 and 660 million years ago (mya), and ended with the geologically abrupt appearance of crown bilaterian phyla that began between 530 and 520 mya. The origin and early evolution of phyla cannot be tracked by fossils during this interval, but molecular phylogenetics permits reconstruction of their branching topology, whereas molecular developmental evidence supports hypotheses for the evolution of the metzoan genome during the rise of complex bodyplans. A flexible architecture of genetic regulation was in place even before the appearance of crown sponges, permitting increases in gene expression events as bodyplan complexity rose. Neoproterozoic bilaterians were chiefly small-bodied but likely diverse, whereas in the earliest Cambrian, between 543 and approximately 530-520 mya, bodies that were complex by marine invertebrate standards evolved in association with body-size increases.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.082901.092917
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    VOLCANOES, FLUIDS, AND LIFE AT MID-OCEAN RIDGE SPREADING CENTERS (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 385-491 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The recent recognition of a potentially vast, unexplored hot microbial biosphere associated with active volcanism along the global mid-ocean ridge network has fundamentally shifted concepts of how planets and life coevolve. Many processes intrinsic to the dynamics of the spreading center volcanic system provide partial or complete nutritional fluxes that support diverse microbial communities that thrive under extreme conditions on and beneath the seafloor. Mantle melting, volcanism, and fluid-rock reactions transport volatiles from the asthenosphere to the hydrosphere. Volcanic heat and exothermic reactions drive circulation of nutrient-rich fluids from which chemosynthetic organisms gain metabolic energy. In turn, many of these organisms symbiotically support macrofaunal communities that populate the vents. Long-term seafloor observatories will allow exploration of linkages between volcanism and this newly discovered biosphere. Such approaches may provide essential new information about our own planet while providing critically needed insights into how we can explore other planets for life.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.141331
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    MODELING COMPLEX, NONLINEAR GEOLOGICAL PROCESSES1 (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 35-64 
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    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract We review selected geological processes to which numerical modeling has been applied, with the aim of describing some of the general approaches and applications of the modeling. All of these examples involve multiphase fluid flow, in some cases coupled with heat transport and phase changes. First, we describe modeling approaches to a human-made geological system-a potential underground radioactive waste repository. Next, we describe recent advances in modeling two-phase flow through random heterogeneous porous media. We review recent modeling studies of fluid processes in magmatic systems, especially focusing on melting and crystallization induced by magma chambers. Finally, several research directions are suggested, including improving our understanding of the linkage between small-scale and field-scale processes, coupling across regimes (e.g., surface water and ground water), and further developments in the modeling of stochastic geological processes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.082801.150140
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    SCALING OF SOIL MOISTURE: A Hydrologic Perspective (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 149-180 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Soil moisture is spatially and temporally highly variable, and it influences a range of environmental processes in a nonlinear manner. This leads to scale effects that need to be understood for improved prediction of moisture dependent processes. We provide some introductory material on soil moisture, and then review results from the literature relevant to a variety of scaling techniques applicable to soil moisture. This review concentrates on spatial scaling with brief reference to results on temporal scaling. Scaling techniques are divided into behavioral techniques and process-based techniques. We discuss the statistical distribution of soil moisture, spatial correlation of soil moisture at scales from tens of meters to thousands of kilometers and related interpolation and regularization techniques, and the use of auxiliary variables such as terrain indices. Issues related to spatially distributed deterministic modeling of soil moisture are also briefly reviewed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.140434
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    MODERN IMAGING USING SEISMIC REFLECTION DATA* (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 259-284 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Imaging using seismic reflection data has undergone tremendous advances over the past few years. The advances have been fostered in part by the availability of faster computers that have made more reliable algorithms for migration imaging feasible. The conventional approach to migration imaging, ray-based Kirchhoff migration, has been improved by the use of multiple-valued traveltime tables, ray amplitudes, and ray phases that can be calculated from various ray-tracing implementations. Wave-equation imaging, based on implementations of solutions of the wave equation, one-way wave equation, and approximations to the Lippmann-Schwinger equation, has become tractable. Wave-equation methods take account of wave phenomena such as focusing, defocusing, and diffraction that are important in many geological environments where imaging is used for petroleum exploration. There have also been applications of various types of migration imaging in basic studies of Earth structure. Such studies have been made to investigate deep Earth structure and large-scale lithospheric structure using waveforms from teleseisms as sources.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.140909
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  • 97
    Digitale Medien
    Digitale Medien
    FOSSIL PLANTS AS INDICATORS OF THE PHANEROZOIC GLOBAL CARBON CYCLE (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 30 (2002), S. 527-556 
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    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Developments in plant physiology since the 1980s have led to the realization that fossil plants archive both the isotopic composition of atmospheric CO2 and its concentration, both critical integrators of carbon cycle processes through geologic time. These two carbon cycle signals can be read by analyzing the stable carbon isotope composition (delta13C) of fossilized terrestrial organic matter and by determining the stomatal characters of well-preserved fossil leaves, respectively. We critically evaluate the use of fossil plants in this way at abrupt climatic boundaries associated with mass extinctions and during times of extreme global warmth. Particular emphasis is placed on evaluating the potential to extract a quantitative estimate of the delta13C of atmospheric CO2 because of the key role it plays in understanding the carbon cycle. We critically discuss the use of stomatal index and stomatal ratios for reconstructing atmospheric CO2 levels, especially the need for adequate replication, and present a newly derived CO2 record for the Mesozoic that supports levels calculated from geochemical modeling of the long-term carbon cycle. Several suggestions for future research using stable carbon isotope analyses of fossil terrestrial organic matter and stomatal measurements are highlighted.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.30.091201.141413
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  • 98
    Digitale Medien
    Digitale Medien
    INNER-CORE ANISOTROPY AND ROTATION (2001)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 29 (2001), S. 47-69 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract This paper reviews recent research focused on the Earth's inner core. Large inner-core traveltime anomalies and the anomalous splitting of core-sensitive free oscillations strongly suggest that the inner core is anisotropic. Initial models involved a simple, constant or depth-dependent cylindrical anisotropy at a level less than a few percent. Recent observations suggest that its eastern hemisphere is largely isotropic, whereas its western hemisphere is highly anisotropic, and there are indications that its top 100 km may be isotropic. The coda of inner-core reflected phases has been used to infer strong heterogeneities with a length scale of just a few kilometers. Thus, a complicated three-dimensional picture of the inner core is beginning to emerge, although it has been suggested that much of this complexity may be the misinterpretation of signals that have their origin in the lowermost mantle. Numerical models of the geodynamo suggest that the inner core may rotate at a slightly different rate than the mantle. Recent seismological estimates based upon traveltime and normal-mode data limit inner-core differential rotation to less than +0.2 degrees per year.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.29.1.47
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  • 99
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    Digitale Medien
    THE ROLE OF PLANTS IN CONTROLLING RATES AND PRODUCTS OF WEATHERING: Importance of Biological Pumping (2001)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 29 (2001), S. 135-163 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The recycling of elements by plants and plant-induced biological activity cause the rates and products of weathering to be markedly different from what would result in abiotic processes. Plants directly control water dynamics, weathering, and the chemistry of weathering solutions, which is clearly exhibited in equatorial areas where old weathering mantles are greatly influenced by biological activity. Depending on the dynamics of plant-induced organometallic compounds, this weathering results in either clayey soils, which are in a dynamic equilibrium sustained by the forest's cycling of elements, or sandy soils. In most places (tropical as well temperate areas), the weathering mantle can be regarded as being in a dynamic equilibrium sustained by plants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.29.1.135
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  • 100
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    TECTONIC EVOLUTION OF THE JAPANESE ISLAND ARC SYSTEM (2001)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 29 (2001), S. 109-134 
    Details
    ISSN: 0084-6597
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Growth of the Japanese arc system, which has mainly taken place along the continental margin of Asia since the Permian, is the result of subduction of the ancient Pacific ocean floor. Backarc basin formation in the Tertiary shaped the present-day arc configuration. The neotectonic regime, which is characterized by strong east-west compression, has been triggered by the eastward motion of the Amur plate in the Quaternary. The tectonic evolution of the Japanese arc system includes formation of rock assemblages common in most orogenic belts. Because the origin and present-day tectonics of these assemblages are better defined in the case of the Japanese arc system, study of the system provides useful insight into orogenesis and continental crust evolution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.earth.29.1.109
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