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DOI | 10.1073/pnas.1709145114 |
Effect of paleoseawater composition on hydrothermal exchange in midocean ridges | |
Antonelli, Michael A.1; Pester, Nicholas J.2; Brown, Shaun T.1,2; DePaolo, Donald J.1,2 | |
2017-11-21 | |
发表期刊 | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA |
ISSN | 0027-8424 |
出版年 | 2017 |
卷号 | 114期号:47页码:12413-12418 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | Variations in the Mg, Ca, Sr, and SO4 concentrations of paleoseawater can affect the chemical exchange between seawater and oceanic basalt in hydrothermal systems at midocean ridges (MOR). We present a model for evaluating the nature and magnitude of these previously unappreciated effects, using available estimates of paleoseawater composition over Phanerozoic time as inputs and Sr-87/Sr-86 of ophiolite epidosites and epidote-quartz veins as constraints. The results suggest that modern hydrothermal fluids are not typical due to low Ca and Sr relative to Mg and SO4 in modern seawater. At other times during the last 500 million years, particularly during the Cretaceous and Ordovician, hydrothermal fluids had more seawater-derived Sr and Ca, a prediction that is supported by Sr isotope data. The predicted Sr-87/Sr-86 of vent fluids varies cyclically in concert with ocean chemistry, with some values much higher than the modern value of similar to 0.7037. The seawater chemistry effects can be expressed in terms of the transfer efficiency of basaltic Ca and Sr to seawater in hydrothermal systems, which varies by a factor of similar to 1.6 over the Phanerozoic, with minima when seawater Mg and SO4 are low. This effect provides a modest negative feedback on seawater composition and Sr-87/Sr-86 changes. For the mid-Cretaceous, the low Sr-87/Sr-86 of seawater requires either exceptionally large amounts of low- temperature exchange with oceanic crust or that the weathering flux of continentally derived Sr was especially small. The model also has implications for MOR hydrothermal systems in the Precambrian, when low-seawater SO4 could help explain low seawater Sr-87/Sr-86. |
英文关键词 | paleoseawater Sr isotopes hydrothermal systems midocean ridges |
领域 | 地球科学 ; 气候变化 ; 资源环境 |
收录类别 | SCI-E |
WOS记录号 | WOS:000416503700044 |
WOS关键词 | CALCIUM-CARBONATE VEINS ; MID-ATLANTIC RIDGE ; SEAWATER CHEMISTRY ; SULFATE CONCENTRATIONS ; GEOCHEMICAL TRANSPORT ; ISOTOPIC CONSTRAINTS ; SECULAR VARIATION ; ATMOSPHERIC CO2 ; SULFUR CYCLE ; RECORD |
WOS类目 | Multidisciplinary Sciences |
WOS研究方向 | Science & Technology - Other Topics |
URL | 查看原文 |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/204820 |
专题 | 地球科学 资源环境科学 气候变化 |
作者单位 | 1.Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA; 2.Lawrence Berkeley Natl Lab, Earth & Environm Sci, Berkeley, CA 94720 USA |
推荐引用方式 GB/T 7714 | Antonelli, Michael A.,Pester, Nicholas J.,Brown, Shaun T.,et al. Effect of paleoseawater composition on hydrothermal exchange in midocean ridges[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,2017,114(47):12413-12418. |
APA | Antonelli, Michael A.,Pester, Nicholas J.,Brown, Shaun T.,&DePaolo, Donald J..(2017).Effect of paleoseawater composition on hydrothermal exchange in midocean ridges.PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,114(47),12413-12418. |
MLA | Antonelli, Michael A.,et al."Effect of paleoseawater composition on hydrothermal exchange in midocean ridges".PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 114.47(2017):12413-12418. |
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