气候变化领域集成服务门户(CCPortal): Origin of chert in Lower Silurian Longmaxi Formation: Implications for tectonic evolution of Yangtze Block; South China

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DOI	10.1016/j.palaeo.2019.05.017
	Origin of chert in Lower Silurian Longmaxi Formation: Implications for tectonic evolution of Yangtze Block; South China
	Lei Z.; Dashtgard S.E.; Wang J.; Li M.; Feng Q.; Yu Q.; Zhao A.; Du L.
发表日期	2019
ISSN	0031-0182
起始页码	53
结束页码	66
卷号	529
英文摘要	Upper Ordovician (Katian) to Lower Silurian (Rhuddanian) strata in the Middle–Upper Yangtze Block, South China contain extensive chert beds, although the origin of microcrystalline silica in these cherts is largely unknown. In this study, the mineralogy and structure of chert as well as major, trace, and rare earth elements are used to determine the origin of microcrystalline silica in 29 chert samples from Longmaxi Formation (Rhuddanian) in Baizitian outcrop, west of Kangdian Uplift (KU). Results show that 21 of the 29 chert samples have a biogenic origin, 2 indicate a hydrothermal origin, and 6 show a mixed origin. Cherts from Baizitian outcrop are compared to contemporaneous cherts deposited east of KU. Cherts both east and west of KU are mainly biogenic in origin, which is attributed to high productivity in the paleo-seaway. Hydrothermal microcrystalline silica is relatively uncommon in the Longmaxi Formation across the Middle-Upper Yangtze Block, and only occurs in Baizitian outcrop. Terrigenous influx contributed to chert accumulation both east and west of KU; however, cherts east of KU received much more clastic material than those in Baizitian outcrop. A comparison of chert composition and geochemistry to geological reconstructions of the Middle-Upper Yangtze Block reveal that accumulation of hydrothermal chert is closely linked to tectonic evolution. During the Early Silurian, the Middle-Upper Yangtze Block was in a compressional tectonic regime with limited heat supply, and hence, low hydrothermal circulation; this is manifested in the paucity of hydrothermal microcrystalline silica in cherts east of KU. In contrast, hydrothermal microcrystalline silica in cherts west of KU is interpreted to have formed in an extensional tectonic regime with sufficient heat supply. This research demonstrates that chert source is, in part, tectonic controlled, and chert geochemistry can be used in reconstructing paleoenvironments. © 2019 Elsevier B.V.
英文关键词	Compressional tectonics; Extensional tectonics; Hydrothermal plume; Microcrystalline silica; Productivity; Rhuddanian
语种	英语
scopus关键词	chert; compression; crystallinity; hydrothermal plume; lithostratigraphy; Ordovician; outcrop; silica; Silurian; tectonic evolution; China; Yangtze Platform
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/150915
作者单位	Department of Earth Sciences, China University of Geosciences, Wuhan, 430074, China; Chinese Academy of Geological Sciences, Beijing, 100037, China; Sedimentary Geology Research, Chengdu Center of China Geological Survey, Chengdu, 610081, China; Applied Research in Ichnology and Sedimentology (ARISE) Group, Department of Earth Sciences, Simon Fraser University, Burnaby, V5A 1S6, Canada; School of Earth Science, Zhejiang University, Zhejiang, 310027, China; State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China
推荐引用方式 GB/T 7714	Lei Z.,Dashtgard S.E.,Wang J.,et al. Origin of chert in Lower Silurian Longmaxi Formation: Implications for tectonic evolution of Yangtze Block; South China[J],2019,529.
APA	Lei Z..,Dashtgard S.E..,Wang J..,Li M..,Feng Q..,...&Du L..(2019).Origin of chert in Lower Silurian Longmaxi Formation: Implications for tectonic evolution of Yangtze Block; South China.Palaeogeography, Palaeoclimatology, Palaeoecology,529.
MLA	Lei Z.,et al."Origin of chert in Lower Silurian Longmaxi Formation: Implications for tectonic evolution of Yangtze Block; South China".Palaeogeography, Palaeoclimatology, Palaeoecology 529(2019).