Hydrothermal activity during Ediacaran-Cambrian transition: Silicon isotopic evidence

	Hydrothermal activity during Ediacaran-Cambrian transition: Silicon isotopic evidence
	Haifeng Fan; Hanjie Wen; Xiangkun Zhu; Ruizhong Hu; Shihong Tian
	2013
发表期刊	Precambrian Research
卷号	224 期号:1 页码:23-35
摘要	Abundant bedded chert deposits occurred at the Ediacaran-Cambrian transition interval at the Yangtze Platform, South China. However, there is not a non-controversial and integrated model for the origin of these chert deposits from trace element patterns and oxygen isotopic evidence. To understand the origin and the oceanic environment of these chert deposits, we analyzed the Si isotopic composition, major and trace elements of chert samples from two stratigraphically correlated sections with a depositional age around 542 Ma. The relationship between Al2O3 content and Si isotopic values indicated three end-member sources of Si derivation. The most negative delta Si-30 values (-0.3% to -0.5%.) reflect the silicon derived from hydrothermal fluids due to intense tectonic activity. The most positive delta Si-30 values (up to +1.2%.) could reflect the increase of Si-30 in the hydrothermal fluid by precipitation, or the signature of seawater. The medium delta Si-30 value (+0.2 parts per thousand to +0.7 parts per thousand) could be interpreted as the mixing of the hydrothermal fluid and volcanic materials with negative delta Si-30 and ambient seawater with positive delta Si-30. It is obvious that the injection of Si-rich hydrothermal fluid would affect the delta Si-30 and trace element distribution of seawater. In addition, we estimated that the delta Si-30 values of Ediacaran-Cambrian transitional seawater range from +2.2 parts per thousand to +3.5 parts per thousand based on assumed fractionation factors -2.3%.< epsilon < -1.0 parts per thousand between precipitated Si in chest deposits and initial dissolved Si in seawater. According to Si isotopic composition and other geochemical evidence, we maintain that hydrothermal activity played an important role not only in the formation of bedded chest and polymetallic ore deposits, but also in the oceanic environment and concurrent evolution of life during Ediacaran-Cambrian transition interval.
收录类别	SCI
语种	英语
文献类型	期刊论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/5123
专题	矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文矿床地球化学国家重点实验室
推荐引用方式 GB/T 7714	Haifeng Fan,Hanjie Wen,Xiangkun Zhu,et al. Hydrothermal activity during Ediacaran-Cambrian transition: Silicon isotopic evidence[J]. Precambrian Research,2013,224(1):23-35.
APA	Haifeng Fan,Hanjie Wen,Xiangkun Zhu,Ruizhong Hu,&Shihong Tian.(2013).Hydrothermal activity during Ediacaran-Cambrian transition: Silicon isotopic evidence.Precambrian Research,224(1),23-35.
MLA	Haifeng Fan,et al."Hydrothermal activity during Ediacaran-Cambrian transition: Silicon isotopic evidence".Precambrian Research 224.1(2013):23-35.

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