ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Coral  (2)
  • Dissolution  (2)
  • 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology  (1)
  • 04.08. Volcanology  (1)
  • Elsevier  (4)
  • American Chemical Society
  • 2015-2019  (4)
  • 1980-1984
  • 1945-1949
  • 1940-1944
Sammlung
Verlag/Herausgeber
Erscheinungszeitraum
Jahr
  • 1
    Publikationsdatum: 2022-05-25
    Beschreibung: This paper is not subject to U.S. copyright. The definitive version was published in Marine Geology 380 (2016): 284–289, doi:10.1016/j.margeo.2016.04.008.
    Beschreibung: Rivers have long been recognized for their ability to shape reef-bound volcanic islands. On the time-scale of glacial–interglacial sea-level cycles, fluvial incision of exposed barrier reef lagoons may compete with constructional coral growth to shape the coastal geomorphology of ocean islands. However, overprinting of Pleistocene landscapes by Holocene erosion or sedimentation has largely obscured the role lowstand river incision may have played in developing the deep lagoons typical of modern barrier reefs. Here we use high-resolution seismic imagery and core stratigraphy to examine how erosion and/or deposition by upland drainage networks has shaped coastal morphology on Tahaa, a barrier reef-bound island located along the Society Islands hotspot chain in French Polynesia. At Tahaa, we find that many channels, incised into the lagoon floor during Pleistocene sea-level lowstands, are located near the mouths of upstream terrestrial drainages. Steeper antecedent topography appears to have enhanced lowstand fluvial erosion along Tahaa's southwestern coast and maintained a deep pass. During highstands, upland drainages appear to contribute little sediment to refilling accommodation space in the lagoon. Rather, the flushing of fine carbonate sediment out of incised fluvial channels by storms and currents appears to have limited lagoonal infilling and further reinforced development of deep barrier reef lagoons during periods of highstand submersion.
    Beschreibung: This project was supported by a Jackson School Distinguished Postdoctoral Fellowship to Michael Toomey and the WHOI Coastal Ocean Institute and Ocean and Climate Change Institute.
    Schlagwort(e): Coral ; Island ; Lagoon ; Dissolution ; Morphology
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Publikationsdatum: 2021-06-30
    Beschreibung: Soil CO2 flux and 222Rn activity measurements may positively contribute to the geochemicalmonitoring of active volcanoes. The influence of several environmental parameters on the gas signals has been substantially demonstrated. Therefore, the implementation of tools capable of removing (or minimising) the contribution of the atmospheric effects from the acquired time series is a challenge in volcano surveillance. Here, we present 4 years-long continuousmonitoring (fromApril 2007 to September 2011) of radon activity and soil CO2 flux collected on the NE flank of Stromboli volcano. Both gases record higher emissions during fall–winter (up to 2700 Bq * m−3 for radon and 750 g m−2 day−1 for CO2) than during spring–summer seasons. Short-time variations on 222Rn activity aremodulated by changes in soil humidity (rainfall), and changes in soil CO2 flux that may be ascribed to variations in wind speed and direction. The spectral analyses reveal diurnal and semi-diurnal cycles on both gases, outlining that atmospheric variations are capable to modify the gas release rate fromthe soil. The long-termsoil CO2 flux shows a slow decreasing trend, not visible in 222Rn activity, suggesting a possible difference in the source depth of the of the gases, CO2 being deeper and likely related to degassing at depth of the magma batch involved in the February–April 2007 effusive eruption. To minimise the effect of the environmental parameters on the 222Rn concentrations and soil CO2 fluxes, two different statistical treatments were applied: the Multiple Linear Regression (MLR) and the Principal Component Regression (PCR). These approaches allow to quantify theweight of each environmental factor on the two gas species and showa strong influence of some parameters on the gas transfer processes through soils. The residual values of radon and CO2 flux, i.e. the values obtained after correction for the environmental influence, were then compared with the eruptive episodes that occurred at Stromboli during the analysed time span (2007–2011) but no clear correlations emerge between soil gas release and volcanic activity. This is probably due to i) the distal location of the monitoring stations with respect to the active craters and to ii) the fact that during the investigated period no major eruptive phenomena (paroxysmal explosion, flank eruption) occurred. Comparison of MLR and PCR methods in time-series analysis indicates thatMLR can bemore easily applied to real time data processing in monitoring of open conduit active volcanoes (like Stromboli) where the transition to an eruptive phase may occur in relatively short times.
    Beschreibung: This researchwas partly funded by ItalianMinistry of University and Research (MIUR) and by University of Torino-Fondazione Compagnia di San Paolo. Additional fundswere provided by the Italian “Presidenza del Consiglio dei Ministri–Dipartimento della Protezione Civile (DPC)” through the DEVnet Project (a cooperative program between the Departments of Earth Sciences of the University of Torino and the University of Florence) and through the “Potenziamento Monitoraggio Stromboli” project. Additional funds for improving our computing hardware were provided by Fondazione Cassa di Risparmio di Torino.
    Beschreibung: Published
    Beschreibung: 65-78
    Beschreibung: 4V. Processi pre-eruttivi
    Beschreibung: JCR Journal
    Schlagwort(e): Stromboli volcano ; Continuous geochemical monitoring ; Soil CO2 flux ; Radon activity ; Environmental parameters ; Time series analyses ; 04.08. Volcanology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Publikationsdatum: 2021-01-14
    Beschreibung: The Marsili Seamount (MS) is an about 3200 m high volcanic complex measuring 70 × 30 km with the top at ~500 m b.s.l. MS is interpreted as the ridge of the 2 Ma old Marsili back-arc basin belonging to the Calabrian Arc–Ionian Sea subduction system(Southern Tyrrhenian Sea, Italy). Previous studies indicate that theMS activity developed between 1 and 0.1 Ma through effusions of lava flows. Here, new stratigraphic, textural, geochemical, and 14C geochronological data from a 95 cm long gravity core (COR02) recovered at 839 m bsl in theMS central sector are presented. COR02 contains mud and two tephras consisting of 98 to 100 area% of volcanic ash. The thickness of the upper tephra (TEPH01) is 15 cm, and that of the lower tephra (TEPH02) is 60 cm. The tephras have poor to moderate sorting, loose to partly welded levels, and erosive contacts, which imply a short distance source of the pyroclastics. 14C dating on fossils above and below TEPH01 gives an age of 3 ka BP. Calculations of the sedimentation rates from the mud sediments above and between the tephras suggest that a formation of TEPH02 at 5 ka BP MS ashes has a high-K calcalkaline affinity with 53 wt.% b SiO2 b 68 wt.%, and their composition overlaps that of the MS lava flows. The trace element pattern is consistent with fractional crystallization from a common, OIB-like basalt. The source area of ashes is the central sector of MS and not a subaerial volcano of the Campanian and/or Aeolian Quaternary volcanic districts. Submarine, explosive eruptions occurred atMS in historical times: this is the first evidence of explosive volcanic activity at a significant (500–800 m bsl) water depth in the Mediterranean Sea.MS is still active, the monitoring and an evaluation of the different types of hazards are highly recommended.
    Beschreibung: Published
    Beschreibung: 764-774
    Beschreibung: 2IT. Laboratori sperimentali e analitici
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Submarine active volcanism ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Publikationsdatum: 2022-05-25
    Beschreibung: This paper is not subject to U.S. copyright. The definitive version was published in Palaeogeography, Palaeoclimatology, Palaeoecology 451 (2016): 73-83, doi:10.1016/j.palaeo.2016.03.018.
    Beschreibung: Sea-level records from atolls, potentially spanning the Cenozoic, have been largely overlooked, in part because the processes that control atoll form (reef accretion, carbonate dissolution, sediment transport, vertical motion) are complex and, for many islands, unconstrained on million-year timescales. Here we combine existing observations of atoll morphology and corelog stratigraphy from Enewetak Atoll with a numerical model to (1) constrain the relative rates of subsidence, dissolution and sedimentation that have shaped modern Pacific atolls and (2) construct a record of sea level over the past 8.5 million years. Both the stratigraphy from Enewetak Atoll (constrained by a subsidence rate of ~ 20 m/Myr) and our numerical modeling results suggest that low sea levels (50–125 m below present), and presumably bi-polar glaciations, occurred throughout much of the late Miocene, preceding the warmer climate of the Pliocene, when sea level was higher than present. Carbonate dissolution through the subsequent sea-level fall that accompanied the onset of large glacial cycles in the late Pliocene, along with rapid highstand constructional reef growth, likely drove development of the rimmed atoll morphology we see today.
    Beschreibung: Support for this work was provided through a Jackson School Distinguished Postdoctoral Fellowship to Michael Toomey.
    Schlagwort(e): Reef ; Coral ; Dissolution ; Late Miocene ; Oxygen isotope stack
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...