Reconstructing Past Seawater Mg/Ca and Sr/Ca from Mid-Ocean Ridge Flank Calcium Carbonate Veins
Reconstructing Past Seawater Mg/Ca and Sr/Ca from Mid-Ocean Ridge Flank Calcium Carbonate Veins
复制标题
从中洋脊侧翼碳酸钙脉重建过去海水的镁钙比与锶钙比
DOI：
10.1126/science.1182252
复制
发表时间：
2010-02-26
期刊：
影响因子：
56.9
通讯作者：
Cooper, Matthew J.
中科院分区：
文献类型：
--
作者：
Coggon, Rosalind M.;Teagle, Damon A. H.;Cooper, Matthew J.
过去的海水化学指标，如Mg/Ca和Sr/Ca比值，提供了固体地球、大气层和水圈之间元素动态交换的记录，以及生命不断演变的影响。我们估计过去的海洋镁/钙和锶/钙比从套房1.6至1.7亿年的碳酸钙静脉沉淀从海脊侧翼玄武岩海水衍生的流体。我们的数据表明，在新近纪之前，海洋Mg/Ca和Sr/Ca比值低于现代海洋。自白垩纪以来海洋扩张的减少，以及由此导致的整个第三纪早期海洋地壳热液交换的缓慢减少，可以解释这些比例最近的上升。
Proxies for past seawater chemistry, such as Mg/Ca and Sr/Ca ratios, provide a record of the dynamic exchanges of elements between the solid Earth, the atmosphere, and the hydrosphere and the evolving influence of life. We estimated past oceanic Mg/Ca and Sr/Ca ratios from suites of 1.6- to 170-million-year-old calcium carbonate veins that had precipitated from seawater-derived fluids in ocean ridge flank basalts. Our data indicate that before the Neogene, oceanic Mg/Ca and Sr/Ca ratios were lower than in the modern ocean. Decreased ocean spreading since the Cretaceous and the resulting slow reduction in ocean crustal hydrothermal exchange throughout the early Tertiary may explain the recent rise in these ratios.