气候变化领域集成服务门户(CCPortal): Climatic and oceanic changes during the Middle-Late Ordovician transition in the Tarim Basin; NW China and implications for the Great Ordovician Biodiversification Event

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DOI	10.1016/j.palaeo.2018.10.032
	Climatic and oceanic changes during the Middle-Late Ordovician transition in the Tarim Basin; NW China and implications for the Great Ordovician Biodiversification Event
	Liu M.; Chen D.; Zhou X.; Yuan W.; Jiang M.; Liu L.
发表日期	2019
ISSN	0031-0182
起始页码	522
结束页码	535
卷号	514
英文摘要	The Middle-Late Ordovician transition (Darriwilian to Sandbian Age) witnessed a major pulse of the Great Ordovician Biodiversification Event (GOBE) and distinctive oceanic geochemical fluctuations, such as coeval negative C and Sr isotope excursions. In this study, investigations into geochemical variations, notably the Hg abundance (or Hg/TOC), have been carried upon the organic-rich black shale of the Middle-Upper Ordovician Saergan Formation to unravel the causes of this pulse. Based on these data, three phases were identified. Phase 1 (0 to 3 m) is characterized by rising Hg/TOC (up to 138 ppb/wt%) and Ti/Al values as well as high CIAcorr (corrected chemical index of alteration) values (68.9–72.3) with negligible enrichment of redox sensitive elements (RSE) and nutrient elements (e.g. U ≤ 5.2 ppm, V ≤ 153 ppm, Mo ≤ 1.8 ppm, P2O5 ≤ 0.2%), suggesting intensified volcanism, which could have emitted significant amounts of greenhouse gases, thereby leading to climate warming. In contrast, Phase 2 (3 to 11 m) is characterized by decreasing Hg/TOC and Ti/Al ratios, relatively low though slightly fluctuating CIAcorr values, generally depleted in RSE (except moderately enriched U up to 14.6 ppm) and increased P/Al and Ba/Al ratios, implying weakening volcanic activity and subsequent climate cooling and the potential for improved seawater ventilation as a result of oceanic upwelling. Phase 3 (Sandbian Age: 11–13 m) witnessed continuous decrease in Hg/TOC ratio, an increase in Ti/Al and CIAcorr values, fairly low values of RSE enrichment and P/Al and Ba/Al ratios, indicating recurrent climate warming, and the potential for slowed oceanic circulation and attenuated upwelling of nutrient-rich deep waters onto the shallow shelf. These changes could have diminished bioproductivity and organic output onto the seafloor. This study offers insights into volcanic-climatic-oceanic interactions during a major pulse of the GOBE around the Middle-Late Ordovician transition while black shales were extensively deposited. © 2018
英文关键词	Black shale; Great Ordovician Biodiversity Event; Mercury concentration; Middle-Late Ordovician; Tarim Basin; Volcanism
语种	英语
scopus关键词	atmosphere-ocean system; black shale; climate change; concentration (composition); cooling; deep water; mercury (element); oceanic circulation; Ordovician; seafloor; seawater; upwelling; volcanism; China; Tarim Basin; Xinjiang Uygur
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151137
作者单位	Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Institutions of Earth Science, Chinese Academy of Sciences, Beijing, 100049, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China; Department of Geology, Northwest University, Xi'an, 710127, China
推荐引用方式 GB/T 7714	Liu M.,Chen D.,Zhou X.,et al. Climatic and oceanic changes during the Middle-Late Ordovician transition in the Tarim Basin; NW China and implications for the Great Ordovician Biodiversification Event[J],2019,514.
APA	Liu M.,Chen D.,Zhou X.,Yuan W.,Jiang M.,&Liu L..(2019).Climatic and oceanic changes during the Middle-Late Ordovician transition in the Tarim Basin; NW China and implications for the Great Ordovician Biodiversification Event.Palaeogeography, Palaeoclimatology, Palaeoecology,514.
MLA	Liu M.,et al."Climatic and oceanic changes during the Middle-Late Ordovician transition in the Tarim Basin; NW China and implications for the Great Ordovician Biodiversification Event".Palaeogeography, Palaeoclimatology, Palaeoecology 514(2019).