کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6436475 1637582 2014 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Selenium isotopes trace anoxic and ferruginous seawater conditions in the Early Cambrian
ترجمه فارسی عنوان
ایزوتوپهای سلنیوم شرایط آب و هوایی دریایی و غیر آهنی را در کامبن زودهنگام ردیابی می کنند
کلمات کلیدی
ایزوتوپ س، تجزیه ایزوتوپ، رسوبات بیرونی و فرآورده، کامبرین، جنوب چین،
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
چکیده انگلیسی


- Se isotopes can trace anoxic and ferruginous seawater conditions.
- Ferruginous conditions must have been present in early Cambrian ocean along the eastern margin of the Yangtze platform.
- Se isotopes are an appropriate geochemical proxy to trace unique oceanic conditions.

Selenium (Se) isotopes can yield substantial isotopic fractionation (up to 20‰) confirmed by experiments and field investigations, depending on various biotic or abiotic redox transformations. Therefore, it is expected that redox changes in the ancient oceans would induce significant isotopic fractionation, and the Se isotopic signatures recorded in old sedimentary rocks might provide new insight into how the redox state of the ancient ocean has evolved. However, previous studies have shown that Se is slightly enriched in the lighter isotope relative to the bulk earth values in most deposited conditions (oxic, anoxic, and even sulfidic). Here, our results reveal that ferruginous conditions can result in excessive accumulation of Se in sediments with an elevated Se/S ratio and significant isotope fractionation (about 6‰), which leads us to propose that Se isotopes are an appropriate geochemical proxy to trace unique oceanic conditions over times. Accordingly, Se isotopic variations measured in three Early Cambrian formations in southern China suggest that anoxic waters with ferruginous conditions must have been present in early Cambrian ocean along the eastern margin of the Yangtze platform, and oceanic circulation was stepwise reorganized. This may have triggered biological diversification from the Ediacaran to the Early Cambrian.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Geology - Volume 390, 18 December 2014, Pages 164-172
نویسندگان
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