کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4699569 1637655 2012 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Predominance of stratified anoxic Yangtze Sea interrupted by short-term oxygenation during the Ordo-Silurian transition
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Predominance of stratified anoxic Yangtze Sea interrupted by short-term oxygenation during the Ordo-Silurian transition
چکیده انگلیسی

The Ordo-Silurian transition was a critical interval in geological history, during which profound biotic, climatic and oceanic changes occurred. In order to explore the oceanic palaeoredox changes, multiple geochemical proxies, including ratios of S/C, FeHR/FeT, FeP/FeHR and DOP values, are presented here from three sections (Wangjiawan, western Hubei, Sanjiaguan, northern Hunan, and Nanbazi, northern Guizhou) across the Ordo-Silurian boundary on the Yangtze Platform. These palaeoredox data indicate a predominance of stratified, anoxic (ferruginous) ocean on the Yangtze block during this transition, which was interrupted by a brief episode of oceanic oxygenation in the early Hirnantian. This oxygenation, temporally coinciding with the end-Ordovician glaciation and global glacio-eustatic sea level fall, likely resulted from enhanced circulation of polar cold, dense oxygen-rich water onto the low-latitude shelf. The prior and subsequent longer-term episodes of anoxic ocean, particularly the later one which started in the late Hirnantian, occurred in parallel with the rapid climatic warming and sea level rise, which could have slowed down oceanic circulation, thereby enhancing oceanic stratification, anoxia and organic preservation. Oceanic redox changes, together with rapid climatic and sea-level fluctuations, were likely responsible for the stepwise massive demise of the Ordo-Silurian biotic crisis.


► S/C, FeHR/FeT, and FeP/FeHR ratios and DOP values were used as the palaeoredox proxies for the Yangtze Sea during Ordo-Silurian ransition.
► Anoxic environment during the Katian, late Hirnantian and Rhuddanian.
► Oxygenated water masses during the early Hirnantian.
► Redox changes, together with other factors, play a significant role in the end-Ordovician mass extinction.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Geology - Volume 291, 6 January 2012, Pages 69–78
نویسندگان
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