气候变化领域集成服务门户(CCPortal): Source of silica and silicification of the lowermost Cambrian Yanjiahe Formation in the Three Gorges area; South China

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DOI	10.1016/j.palaeo.2020.109697
	Source of silica and silicification of the lowermost Cambrian Yanjiahe Formation in the Three Gorges area; South China
	Chang S.; Zhang L.; Clausen S.; Feng Q.
发表日期	2020
ISSN	0031-0182
卷号	548
英文摘要	The rise of siliceous organisms is generally considered to have driven the abrupt decrease of silica in the ocean during the Ediacaran-Cambrian (E-C) interval, even if the exact timing and biological triggers of this event are still debated. Although Ediacaran-Cambrian chert depositions are widely distributed, multiple evidences converge to support their hydrothermal origin. In this study, we provide petrographic study supplemented by elemental concentration, SEM and Raman spectral data on the siliceous rocks from the Yanjiahe Formation (the Three Gorges area, South China), in order to ascertain the origin of included silica and discuss the involved processes of silica deposition. Contrary to most previous studies, our analyses suggest that studied cherts mainly resulted from biogenic silica, and subsidiary from abiotic precipitation influenced by surrounding hydrothermal activity and from detrital input. The deposition model of silica includes direct deposition of siliceous bioclasts, secondary replacement of carbonate by dissolved biosilica, and microbial induced silicification from seawater. The sink of silica recorded in the Yanjiahe Formation was characterized of a transition from typical Precambrian to Phanerozoic process. In addition, micropalaeontological and taphonomical analyses of the Yanjiahe Formation revealed two pulses of microfossil abundance and diversity in the Fortunian and Stage 2, respectively. They can be correlated with a regression and an enrichment in dissolved phosphate that probably derived from enhanced detrital flux. © 2020 Elsevier B.V.
英文关键词	Acritarch; Biogenic deposition; Petrology; Phosphate; Silica cycle; Silicification
语种	英语
scopus关键词	acritarch; Cambrian; carbonate; hydrothermal activity; microfossil; petrology; Phanerozoic; phosphate; Precambrian; seawater; silicate; silicification; China; Three Gorges; Acritarcha
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/150521
作者单位	School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Wuhan), Wuhan, Hubei 430074, China; Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, Lille, F-59000, France
推荐引用方式 GB/T 7714	Chang S.,Zhang L.,Clausen S.,et al. Source of silica and silicification of the lowermost Cambrian Yanjiahe Formation in the Three Gorges area; South China[J],2020,548.
APA	Chang S.,Zhang L.,Clausen S.,&Feng Q..(2020).Source of silica and silicification of the lowermost Cambrian Yanjiahe Formation in the Three Gorges area; South China.Palaeogeography, Palaeoclimatology, Palaeoecology,548.
MLA	Chang S.,et al."Source of silica and silicification of the lowermost Cambrian Yanjiahe Formation in the Three Gorges area; South China".Palaeogeography, Palaeoclimatology, Palaeoecology 548(2020).