New age constraints on Aptian evaporites and carbonates from the South Atlantic: Implications for Oceanic Anoxic Event 1a
New age constraints on Aptian evaporites and carbonates from the South Atlantic: Implications for Oceanic Anoxic Event 1a
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DOI：
10.1130/g38886.1
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发表时间：
2017-06
期刊：
影响因子：
5.8
通讯作者：
L. R. Tedeschi;H. Jenkyns;S. Robinson;A. Sanjinés;M. C. Viviers;C. Quintaes;J. C. Vazquez
中科院分区：
文献类型：
--
作者：
L. R. Tedeschi;H. Jenkyns;S. Robinson;A. Sanjinés;M. C. Viviers;C. Quintaes;J. C. Vazquez
南大西洋（Campos和Santos盆地）浅水和深水碳酸盐岩的高分辨率碳同位素（δ 13c）剖面与地层校准良好的特提斯剖面进行了对比，将南大西洋主要蒸发岩沉积的结束时间限制在早期阿普tian海洋缺氧事件（OAE） 1a段。异常广泛的蒸发岩沉积可能减少了全球溶解的硫酸盐库存，可能通过减少硫酸盐还原而增加了全球有机质的保存；这可以解释OAE 1a在时间上与这段时间内戏剧性的负硫同位素偏移之间的巧合。因此，除了同时期Ontong爪哇高原的喷发外，南大西洋的打开可能对OAE 1a的成因和特征起了重要作用。
High-resolution carbon isotope (δ 13 C) profiles from shallow- and deep-water carbonates in the South Atlantic (Campos and Santos Basins) are here correlated to stratigraphically well calibrated Tethyan sections, constraining the end of major evaporite deposition in the South Atlantic to the early Aptian Oceanic Anoxic Event (OAE) 1a interval. The unusually extensive evaporite deposition would have reduced the global dissolved sulfate inventory, possibly increasing global preservation of organic matter by decreasing sulfate reduction; this could explain the coincidence in timing between OAE 1a and the dramatic negative sulfur isotope excursion over this interval. Therefore, in addition to the coeval eruption of the Ontong Java Plateau, the opening of the South Atlantic may have played an important role in the genesis and character of OAE 1a.