کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4737589 1640962 2007 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Variation in production, input and preservation of metastable calcium carbonate off Somalia during the last 90,000 years
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Variation in production, input and preservation of metastable calcium carbonate off Somalia during the last 90,000 years
چکیده انگلیسی

To improve our understanding of the Late Pleistocene and Holocene carbonate system of the western Arabian Sea a high-resolution sedimentary record off Somalia has been analysed. The 15.26-m-long piston core 905 comprises a complete record of the last 90,000 years. We have measured concentrations of carbonate minerals, i.e., aragonite, calcite, Mg-calcite, and element ratios (Sr/Ca) together with pteropod counts and an estimation of the preservation state of pteropod shells to trace temporal changes in carbonate production and preservation.The Sr/Ca ratio shows strong similarities to the aragonite percentage and the δ18O record of the planktic foraminifer Neogloboquadrina dutertrei. High Sr/Ca ratios together with fragments of corals found in the coarse fraction indicate that most of the aragonite is of shallow water origin (high-Sr aragonite) and pteropods contribute much less than expected. High resuspensional input of shallow-marine aragonite occurs during sea-level highstands (interglacials) and low input during lowstands (glacials).The Mg-calcite concentration record resembles the whole pteropod abundance and pteropod shell preservation records confirming the use of Mg-calcite in combination with pteropod preservation proxies to reconstruct past fluctuations in carbonate dissolution. Preservation of aragonite and Mg-calcite increases during stadials, H-equivalents, YD and late Marine Isotope Stage (MIS) 3. During late MIS 5/early MIS 4 and in the Late Holocene absence of few pteropods as well as low Mg-calcite weight percentages point to strong dissolution of aragonite and Mg-calcite.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Quaternary Science Reviews - Volume 26, Issues 19–21, October 2007, Pages 2674–2683
نویسندگان
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