کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4690491 | 1636144 | 2009 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Isotopic composition of a large photosymbiotic foraminifer: Evidence for hypersaline environments across the Great Australian Bight during the late Pleistocene
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Isotopic composition of a large photosymbiotic foraminifer: Evidence for hypersaline environments across the Great Australian Bight during the late Pleistocene Isotopic composition of a large photosymbiotic foraminifer: Evidence for hypersaline environments across the Great Australian Bight during the late Pleistocene](/preview/png/4690491.png)
چکیده انگلیسی
Analysis of carbon and oxygen isotopic compositions of large benthic foraminifera tests (Marginopora vertebralis) that lived in the Great Australian Bight during the late Pleistocene, reveal that the tests are enriched by 1 to 3Ⱐin both 18O and 13C relative to modern specimens from the same region. The intolerance of M. vertebralis for cool waters negates lower ocean water temperature as an explanation for such high δ18O values. The oxygen isotopic compositions are thus interpreted to reflect tests secreted in hypersaline waters of up to 56 ppt salinity, concentrated from seawater by evaporation. M. vertebralis thrives today in waters of similar salinity at Shark Bay, Western Australia. The Pleistocene sedimentary assemblage supports an interpretation that environments broadly similar to those in outer modern-day Shark Bay were wide spread across the Great Australian Bight during portions of marine isotope stages 2, 3 and 4. The high δ13C values of the Pleistocene M. vertebralis are interpreted to reflect enhanced photosynthetic activity that depletes dissolved carbonate in 12C in such shallow, saline settings. These hypersaline environments formed during periods of lower sea-level when shallow-waters (< 20 m depth) extended from the shoreline over ~ 100 km across what is currently a relatively deep shelf. This study indicates that shelf bathymetry was a critical determinant of past environments of deposition across the Great Australian Bight.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Sedimentary Geology - Volume 213, Issues 3â4, 15 January 2009, Pages 113-120
Journal: Sedimentary Geology - Volume 213, Issues 3â4, 15 January 2009, Pages 113-120
نویسندگان
John M. Rivers, T. Kurt Kyser, Noel P. James,