ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
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
    facet.materialart.
    Unknown
    Large and rapid climate variability during the Messinian salinity crisis: Evidence from deuterium concentrations of individual biomarkers (2001)
    GSA, Geological Society of America
    In:  Geology, 29 (9). pp. 799-802.
    Details
    Publication Date: 2016-04-15
    Description: During the Messinian, 6 m.y. ago, massive sea-level fall and widespread deposition of evaporites occurred in the Mediterranean Sea when it became isolated from the world oceans. Here we present the first hydrogen isotope data from individual sedimentary biomarkers, n-alkanes and isoprenoids, that tracked climatically driven hydrographic changes in response to extreme evaporation during the Messinian salinity crisis. The stable hydrogen and carbon isotope compositions of these biomarkers show a range of 160‰ in δD values and 14‰ in δ13C values, and roughly covary. This indicates that the source waters of the biomarkers were therefore in some cases extremely enriched in deuterium, having average δD as great as +66‰ VSMOW (Vienna standard mean ocean water). Such values are only known from desert climates today. Because the offset between the δD values of n-alkanes and isoprenoids preserved in the Miocene sedimentary rocks is similar to the offset found in modern biological samples, we conclude that diagenesis did not significantly affect the primary deuterium concentrations.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
  • 2
    facet.materialart.
    Unknown
    Dolomite formation within the methanogenic zone induced by tectonically driven fluids in the Peru accretionary prism (2011)
    GSA, Geological Society of America
    In:  Geology, 39 (6). pp. 563-566.
    Details
    Publication Date: 2017-07-28
    Description: Early diagenetic dolomite formation in methanogenic marine sediments is enigmatic because acidifi cation by CO2, a by-product of methanogenesis, should lead to carbonate dissolution and not precipitation. However, petrographic relationships indicate that dolomite breccia layers with δ13C values of ~+15‰, recovered from the lower slope of the Peru continental margin (Ocean Drilling Program Site 1230), formed deep in the methanogenic zone during tectonic activity of a décollement. Based on radiogenic Sr isotope ratios (87Sr/86Sr 〉 0.711) and positive δ18O values (+6‰), we present evidence that the dolomite breccias mainly formed from fl uids originating from deep sedimentary units within the accretionary prism, where they interacted with continental crust and/or siliciclastic rocks of continental affi nity. Due to silicate alteration and dehydration, such fl uids are likely alkaline and thus have the potential to neutralize the acidifi cation imposed by the high dissolved CO2 concentrations. This scenario provides a potential mechanism by which dolomite formation can be induced deep in a highly active methanogenic zone.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...