ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Call number: M 09.0339
    Type of Medium: Monograph available for loan
    Pages: XIV, 365 S. , Ill., graph. Darst.
    ISBN: 3934504124
    Series Statement: Dahlem workshop report DWR 89
    Classification: D.3.
    Location: Upper compact magazine
    Branch Library: GFZ Library
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    In:  Manganese Mineralization: Geochemistry and Mineralogy of Terrestrial and Marine Deposits ; Year: 1997 ; Pages: 123-138
    Publication Date: 2013-10-16
    Type: http://purl.org/eprint/type/BookItem
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    In:  Earth and Planetary Science Letters ; Year: 1996 ; Volume: 141 ; Pages: 213-226
    Publication Date: 2013-10-16
    Description: The direct measurement of the ratio of cosmogenic 10Be (T½ = 1.5 Ma) to stable terrigenously sourced 9Be in deep seawater or marine deposits can be used to trace water mass movements and to quantify the incorporation of trace metals into the deep sea. In this study a SIMS-based technique has been used to determine the 10Be/9Be ratios of the outermost millimetre of hydrogenetic ferromanganese crusts from the worlds oceans. 10Be/9Be ratios, time-corrected for radioactive decay of cosmogenic 10Be using 234U/238U, are in good agreement with AMS measurements of modem deep seawater. Ratios are relatively low in the North and equatorial Atlantic samples (0.4-0.5 X 10-7. In the Southwest Atlantic ratios increase up to 1 X 10-7, they vary between 0.7 and 1.0 X -7 in Indian Ocean samples, and have a near constant value of 1.1 ± 0.2 X 10-7 for all Pacific samples. If the residence time of 10Be 10Beγ10 in deep water is constant globally, then the observed variations in 10Be/9Be ratios could be caused by accumulation of 10Be in deep water as it flows and ages along the onveyor, following a transient depletion upon its formation in the Northern Atlantic. In this view both 10Be and 9Be reach local steady-state concentration in Pacific deep water and the global γ10Be ≅ 600 a. An alternative possibility is that the Be isotope abundances are controlled by local scavenging. For this scenario γ10Be would vary according to local particle concentration and would ≅ 600 a in the central Pacific, but γ10Be ≅ 230 a in the Atlantic. Mass balance considerations indicate that hydrothermal additions of 9Be to the oceans are negligible and that the dissolved riverine source is also small. Furthermore, aeolian dust input of 9Be appears insuffkient to provide the dissolved 9Be inventory. The dissolution of only a small proportion (2%) of river-derived particulates could in principle supply the observed seawater 9Be content. If true, ocean margins would be the sites for 9Be addition. Due to the particle-reactive nature of Be, these would also be the primary sites of Be removal. A possible net result of horizontal water masses passing through these marginal areas might be a decrease in seawater 10Be/9Be, and establishment of a relatively constant 9Be concentration. As γ10Be (~ 600 a) is less than the apparent age of deep water in the Pacific (~ 1500 a), the Pacific record of 10Be/9Be is not expected to show secular variations due to changes in deep-water flow, despite the large variations in 10Be/9Be between different water masses. Because of this insensitivity to deep-water flow, however, it is suggested that the 10Be/9Be ratio, determined in the authigenic phase of marine sediments or hydrogenetic precipitates, should be a suitable tool for monitoring changes in continental input or cosmic ray intensity on longer time scales.
    Type: http://purl.org/escidoc/metadata/ves/publication-types/article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    facet.materialart.
    Unknown
    In:  Geochimica et Cosmochimica Acta ; Year: 1996 ; Volume: 60 ; Issue: 24 ; Pages: 4957-4963
    Publication Date: 2014-06-19
    Description: The lead isotope composition of ocean water is not well constrained due to contamination by anthropogenic lead. Here the global distribution of lead isotopes in deep ocean water is presented as derived from dated (ca. 100 ka) surface layers of hydrogenetic Fe-Mn crusts. The results indicate that the radiogenic lead in North Atlantic deep water is probably supplied from the continents by river particulates, and that lead in Pacific deep water is similar to that characteristic of island and continental volcanic arcs. Despite a short residence time in deep water (80- 100 a), the isotopes of lead appear to be exceedingly well mixed in the Pacific basin. There is no evidence for the import of North Atlantic deep water-derived lead into the Pacific ocean, nor into the North Indian Ocean. This implies that the short residence time of lead in deep water prohibits advection over such long distances. Consequently, any climate-induced changes in deep-water flow are not expected to result in major changes in the seawater Pb-isotope record of the Pacific Ocean.
    Type: http://purl.org/escidoc/metadata/ves/publication-types/article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2013-10-16
    Type: http://purl.org/escidoc/metadata/ves/publication-types/article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 1996-09-01
    Description: Zeolites are present in altered pyroclastic rocks at many localities in Greece, and large deposits of potential economic interest are present in three areas: (1) the Evros region of the province of Thrace in the north-eastern part of the Greek mainland; (2) the islands of Kimolos and Poliegos in the western Aegean; and (3) the island of Samos in the eastern Aegean Sea. The deposits in Thrace are of Eocene-Oligocene age and are rich in heulandite and/or clinoptilolite. Those of Kimolos and Poliegos are mainly Quaternary and are rich in mordenite. Those of Samos are Miocene, and are rich in clinoptilolite and/or analcime. The deposits in Thrace are believed to have formed in an open hydrological system by the action of meteoric water, and those of the western Aegean islands in a similar way but under conditions of high heat flow, whereas the deposits in Samos were formed in a saline-alkaline lake. ©1996 Springer-Verlag
    Print ISSN: 0026-4598
    Electronic ISSN: 1432-1866
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2012-10-01
    Description: The Úrkút (Hungary) manganese (Mn) ore, hosted by Jurassic black shale, was studied using high-resolution mineralogical, microtextural, and chemical methods. Two independent superimposed biostructures were identified consisting of rhythmic laminations that provide important proxies for paleoenvironments and duration of ore formation. Millimeter-scale laminae reflect a depositional series of Fe-rich biomats, mineralized microbially produced sedimentary structures. These biomats formed at the sediment-water interface under dysoxic and neutral pH conditions by enzymatic Fe 2+ oxidizing processes that may have developed on a daily to weekly growth cycle. The early diagenetic sedimentary ore is composed of Ca rhodochrosite, celadonite, and smectite, and also shows a 100-μm-scale element oscillation that produces Mn(Ca)-rich and Si(Fe clay)-rich microlaminae. This microlamination may reflect a 10 h to daily rhythmicity produced by the growth of microbial communities. If true, then the giant Úrkút ore deposit may have formed over hundreds of years, rather than hundreds of thousands of years as previously thought.
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    facet.materialart.
    Unknown
    Mineralogical Society of America
    Publication Date: 2017-06-02
    Description: Marine iron–manganese oxide coatings occur in many shallow and deep-water areas of the global ocean and can form in three ways: 1) Fe–Mn crusts can precipitate from seawater onto rocks on seamounts; 2) Fe–Mn nodules can form on the sediment surface around a nucleus by diagenetic processes in sediment pore water; 3) encrustations can precipitate from hydrothermal fluids. These oxide coatings have been growing for thousands to tens of millions of years. They represent a vast archive of how oceans have changed, including variations of climate, ocean currents, geological activity, erosion processes on land, and even anthropogenic impact. A growing toolbox of age-dating methods and element and isotopic signatures are being used to exploit these archives.
    Print ISSN: 1811-5209
    Electronic ISSN: 1811-5217
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 1996-09-01
    Description: Hydrogenetic ferromanganese crusts reflect the chemical conditions of the sewater from which they formed. Fine-scale geochemical analysis of crust layers in combination with age determinations can therefore be used to investigate paleoceanographic changes which are recorded in geochemical gradients in the crusts. At Tropic seamount (off northwest Africa), uniform crust growth influenced by terrigenous input from the African continent occurred during approximately the past 12 Ma. Phosphatization of these crusts is minor. In contrast, crusts from Lion seamount, located between Madeira and the Portuguese coast, display a much more variable growth history. A pronounced increase in Ni, Cu, and Zn is observed in some intervals of the crusts, which probably reflects increased surface productivity. A thick older phosphatized generation occurs in many samples. Hydrographic profiles indicate that Mediterranean outflow water (MOW) may play an important role in the composition of these crusts.10Be dating of one sample confirms that the interruption of the MOW during the Messinian salinity crisis (6.2–5 Ma ago) resulted in changes in element composition. Sr-isotope dating of the apatite phase of the old crust generation has been carried out to obtain a minimum age for the older generation of Atlantic crusts and to determine whether crust phosphatization in the Atlantic can be related to phosphatization episodes recorded in Pacific crusts. The preliminary data show that the old phosphatized crust generation might be as old as approximately 30–40 Ma. ©1996 Springer-Verlag
    Print ISSN: 1437-3254
    Electronic ISSN: 1437-3262
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2015-02-04
    Description: Biological carbon fixation is limited by the supply of Fe in vast regions of the global ocean. Dissolved Fe in seawater is primarily sourced from continental mineral dust, submarine hydrothermalism, and sediment dissolution along continental margins. However, the relative contributions of these three sources to the Fe budget of the...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...