Evolution of the composition of seawater through geologic time, and its influence on the evolution of life
Evolution of the composition of seawater through geologic time, and its influence on the evolution of life
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地质时期海水成分的演变及其对生命进化的影响
DOI：
10.1016/j.gr.2007.10.006
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发表时间：
2008-08
影响因子：
6.1
通讯作者：
Ishikawa, Tomoko
中科院分区：
文献类型：
--
作者：
Li, Yong;Yamamoto, Shinji;Shibuya, Takazo;Kitajima, Kouki;Sawaki, Yusuke;Hirata, Takafumi;Shu, Degan;Han, Jian;Komiya, Tsuyoshi;Ishikawa, Tomoko
早期地球表面环境的氧化还原状态仍存在争议，缺乏详细定量的估计。为了消除次生碳酸盐和碎屑物质的污染，估计海水随时间的氧化还原情况，我们对浅海和深海沉积物中原生沉积构造岩石中的碳酸盐矿物进行了主量、微量和稀土元素的原位分析。根据给定大气co2含量（pCO2）和海水Ca含量参数下碳酸盐矿物的Ce含量和异常情况，分别计算了浅层和深层海水的氧含量。结果表明，至少在1.9 Ga之前，深海的氧含量一直很低且保持不变。2.7 Ga后浅层海水氧含量有所增加，但有波动。它在2.5和2.3 Ga时变得相当高，但最终在显生宙后增加。此外，高pco2条件的计算表明，即使在太古宙，海水的氧含量也比现在高，这表明在整个地质时期，海水的pco2含量相对较低。根据华南三峡地区碳酸盐矿物组成的详细计算表明，在雪球地球之后至埃迪卡拉晚期，海水氧含量较低，在埃迪卡拉晚期有所增加，在前寒武纪-寒武纪和Nemakit/ daldyian - tommotian界线附近明显减少。这些变化可能是由全球回归和甲烷水合物溶解引起的。
The redox state of the surface environment of the early Earth is still controversial, and a detailed and quantitative estimate is still lacking. We carried out in-situ analyses of major, trace, and rare-earth elements of carbonate minerals in rocks with primary sedimentary structures in shallow and deep sea-deposits, in order to eliminate secondary carbonate and contamination of detrital materials, and to estimate the redox condition of seawater through time. Based on the Ce content and anomalies of the carbonate minerals at given parameters of atmospheric CO2content (pCO2) and Ca content of seawater, we calculated the oxygen contents of shallow and deep seawater, respectively. The results show that the oxygen content of the deep sea was low and constant until at least 1.9 Ga. The oxygen content of shallow seawater increased after 2.7 Ga, but fluctuated. It became quite high at 2.5 and 2.3 Ga, but eventually increased after the Phanerozoic. In addition, the calculation of a high pCO2condition shows that seawater was more oxic even in the Archean than at present, suggesting a relatively low pCO2through geologic time. Our detailed calculations from compositions of carbonate minerals in Three Gorge area, south China show a low oxygen content of seawater after the Snowball Earth until the late Ediacaran, an increase in the late Ediacaran, and a significant decrease around the Precambrian–Cambrian and Nemakit/Daldynian–Tommotian boundaries. These variations were possibly caused by global regression and dissolution of methane hydrates.
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影响因子：
9.8
作者：
M. Benarie
通讯作者：
M. Benarie
影响因子：
5
作者：
G. Klinkhammer;H. Elderfield;J. Edmond;A. Mitra
通讯作者：
G. Klinkhammer;H. Elderfield;J. Edmond;A. Mitra
影响因子：
56.9
作者：
Konhauser, Kurt O.;Lalonde, Stefan V.;Holland, Heinrich D.
通讯作者：
Holland, Heinrich D.
影响因子：
5.2
作者：
K. Condie
通讯作者：
K. Condie
影响因子：
5.8
作者：
S. Dasgupta;Supriya Roy;M. Fukuoka
通讯作者：
S. Dasgupta;Supriya Roy;M. Fukuoka