Digital Library
Close Browse articles from a journal
 
<< previous    next >>
     Journal description
       All volumes of the corresponding journal
         All issues of the corresponding volume
           All articles of the corresponding issues
                                       Details for article 5 of 13 found articles
 
 
  Early diagenetic overprint in Caribbean sediment cores and its effect on the geochemical composition of planktonic foraminifera
 
 
Title: Early diagenetic overprint in Caribbean sediment cores and its effect on the geochemical composition of planktonic foraminifera
Author: M. Regenberg
D. Nürnberg
J. Schönfeld
G.-J. Reichart
Appeared in: Biogeosciences
Paging: Volume 4 (2007) nr. 6 pages 957-973
Year: 2007
Contents: Early diagenetic features are noticed in the vicinity of carbonate platforms. Planktonic foraminifera of two tropical Atlantic deep-sea sediment cores show the strict relation between micro-scale euhydral crystallites of inorganic precipitates, higher oxygen isotope values and Mg/Ca ratios, and lower Sr/Ca ratios than expected for their pelagic environment in the time interval of ~100 000–550 000 calendar years before present. Laser ablation Mg/Ca (Sr/Ca) of crystallite-bearing foraminiferal chamber walls revealed 4–6 times elevated (2–3 times depleted) ratios, when ablating the diagenetic overgrowth. Crystalline overgrowth in proportion of 10–20% are estimated to cause the observed geochemical alteration. The extent of foraminiferal Mg/Ca alteration, moreover, seems to be controlled by the composition of the bulk sediment, especially the content of high-magnesium calcite. Anomalous ratios of >6 mmol/mol only occur, when high-magnesium calcite has dissolved within the sediment. The older parts (back to ~800 kyrs) of the records are characterized by similar trends of Mg/Ca and Sr/Ca. We discuss possible scenarios to accommodate the obtained geochemical information.
Publisher: Copernicus GmbH (provided by DOAJ)
Source file: Elektronische Wetenschappelijke Tijdschriften
 
 

                             Details for article 5 of 13 found articles
 
<< previous    next >>
 
 Koninklijke Bibliotheek - National Library of the Netherlands