The data portal offers an integrative "one-stop-stop" framework for coherent discovery, visualization,
download and dissemination of scientific information originating from nationally operated research
platforms and monitoring facilities (vessels, observatories, alert systems). The content offered
originates from distinct content providers by German marine research institutions
(see the About page) ranging from cruise-related
metadata to reports, publications, data (archived and near real time) and data products.
The portal is based on open technologies and access is freely available for scientists, funding
agencies and the public (no registration is required).
While we have many intensive efforts to provide well harmonized content, there is still much work to be
done, in particular under "more services". Please help us improving our services and content by filling
out our feedback form.
Diagenesis of carbonates in deep-sea sediments - evidence from Sr/Ca ratios and interstitial dissolved Sr (super 2+) data
Baker, Paul A.; Gieskes, Joris M.; Elderfield, Harry
Laboratory determinations of the distribution coefficient of strontium in calcite (k Sr ) have confirmed the earlier results of Katz et al. (1972). In addition, we observed that at higher concentrations of strontium, values of k Sr were somewhat lowered. Chemical analyses of several deep-sea carbonate sediment sections and their associated porewaters (DSDP Sites 288, 289, 315, 317, and 357) as well as previously published data of other workers (DSDP Sites 116 and 305) have been used to demonstrate that these k Sr values are appropriate for use in diagenetic studies. We have successfully modeled the distribution of strontium in the pore waters and sediments. As a result, we conclude that recrystallization of these carbonates (and many other limestones as well) is essentially isochemical, the cement being derived from within the formation. Advective fluid flow through the rock is unnecessary to explain its lithification. Recrystallization of the bulk of the calcite in deep-sea sections is largely complete within the upper few hundred meters, but cementation is generally a later process. These results have important implications for the study of oxygen isotopic compositions of foraminifers and coccoliths in many sediments older than about 20 m.y. B.P. From correlations between changes in Sr/Ca and Mg/Ca ratios of recrystallized carbonates of DSDP Site 305 a distribution coefficient of magnesium in calcite sediments of 8.1 x 10- 4 ( nearly equal 5 degrees C) has been estimated. This value is many times smaller than previously published values.