Calcium isotopic fractionation during travertine deposition under different hydrodynamic conditions: Examples from Baishuitai (Yunnan, SW China)

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	Calcium isotopic fractionation during travertine deposition under different hydrodynamic conditions: Examples from Baishuitai (Yunnan, SW China)
	Jiubin Chen; Hao Yan; Anne-Désirée Schmitt; Zaihua Liu; Sophie Gangloff; Hailong Sun; François Chabaux
刊名	Chemical Geology
	2016
卷号	426 期号:1 页码:60-70
英文摘要	Revealing the potential of Ca isotopes in the research of travertine formation processes is the principal goal of this sludy. To achieve this, the hydrochemistry, travertine precipitation rales, and variations in Ca isolopic compositions (delta Ca-44/40) of present-day endogenic (Lhermogenic) travertine in two differem hydrodynamic systems (canal and pool) are studied at Baishuilai (Yunnan, SW China). In the canal, where the travertine precipitation is faster, delta(44/40) Ca values of both solution and travertine show a downstream increase, with Ca2+ isotopic fractionation (Delta(44/40) CaCaCo3-aq) equal to similar to-1.6 parts per thousand. Compared to the canal, Ca isotopic fractionation between travertine and aqueous Cat is smaller (Delta Ca-44/40(CaCO3-aq) approximate to -1 2 parts per thousand) in the pools where travertine precipitation rates are lower.The spatial variations in delta Ca-44/40 values of solution and travertine are related to the amount of Ca removed from the solution when delta Ca-44/40 values of spring water remain stable. In addition, the results confirm the control of precipitation rates on Ca isotopic fractionation between calcite and parent aqueous Ca2+ using natural samples. The observed negative correlation between Delta Ca-44/40(CaCO3-aq) and travertine precipitation rates can be explained by the steady-state kinetic surface reaction model proposed by DePaolo (2011), with equilibrium and kinetic fractionation factors of alpha(eq) = 1.0000 +/- 0.0001 and alpha(f) = 0.9983 +/- 0.0002, respectively. An important consequence of this study is that Ca isotopes in travertine systems are good tools to have access to variations of delta Ca-44/40(aq) which are directly linked to the amount of precipitated Ca. This could then be useful for reconstructing past hydrodynamic conditions when applied to travertine core data.
学科主题	环境地球化学
语种	英语
公开日期	2017-05-26
内容类型	期刊论文
源URL	[http://ir.gyig.ac.cn:8080/handle/352002/6150]
专题	地球化学研究所_环境地球化学国家重点实验室_环境地球化学国家重点实验室_期刊论文
推荐引用方式 GB/T 7714	Jiubin Chen,Hao Yan,Anne-Désirée Schmitt,et al. Calcium isotopic fractionation during travertine deposition under different hydrodynamic conditions: Examples from Baishuitai (Yunnan, SW China)[J]. Chemical Geology,2016,426(1):60-70.
APA	Jiubin Chen.,Hao Yan.,Anne-Désirée Schmitt.,Zaihua Liu.,Sophie Gangloff.,...&François Chabaux.(2016).Calcium isotopic fractionation during travertine deposition under different hydrodynamic conditions: Examples from Baishuitai (Yunnan, SW China).Chemical Geology,426(1),60-70.
MLA	Jiubin Chen,et al."Calcium isotopic fractionation during travertine deposition under different hydrodynamic conditions: Examples from Baishuitai (Yunnan, SW China)".Chemical Geology 426.1(2016):60-70.