Possible triggers of the seawater sulfate S-isotope increase between 55 and 40 million years ago
Possible triggers of the seawater sulfate S-isotope increase between 55 and 40 million years ago
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DOI：
10.1016/j.chemgeo.2020.119788
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发表时间：
2020-07
期刊：
影响因子：
3.9
通讯作者：
W. Yao;A. Paytan
中科院分区：
文献类型：
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作者：
W. Yao;A. Paytan
地球系统在新生代经历了从温室状态到冰窖状态的气候转变，这可能是由构造和轨道过程引起的。这种转变引发了许多环境变化，包括海平面波动、海水化学以及碳、硫和其他元素的生物地球化学循环。由于较好的生物地层格架和分析技术，通过分析海相重晶石和碳酸盐伴生硫酸盐（CAS），获得了高时间分辨率的海水硫酸盐s同位素数据（δ34Ssw）。这些数据为这段时间内全球生物地球化学循环的变化及其潜在原因提供了新的见解。本文综述了近6500万年来有关δ 34ssw的最新研究成果，重点讨论了始新世早期至中期1500万年期间硫旋回上升5‰的最显著扰动。我们讨论了迄今为止提出的δ 34ssw偏移的可能原因，包括与黄铁矿形成和埋藏有关的幅度、位置或分馏的变化，硫酸盐输入海洋的变化，以及海洋环流的变化。我们提出了一些新的地球化学数据和模型如何提高我们对影响全球硫循环的各种地球表面过程的理解，并概述了解释δ 34ss波动的其他地质区间的框架。
The Earth system experienced a climatic transition from a greenhouse state to an icehouse state over the Cenozoic, which may have been induced by tectonic and orbital processes. This transition has triggered many environmental changes including fluctuations in sea levels, seawater chemistry, and biogeochemical cycles of carbon, sulfur, and other elements. Owing to a better-resolved biostratigraphic framework and analytical techniques, high temporal resolution seawater sulfate S-isotope data (δ34Ssw) have become available through the analysis of marine barite and carbonate associated sulfate (CAS). These data provide new insight into changes in global biogeochemical cycles over this time interval and their potential causes. This study presents a review of recent work on the δ34Sswfor the past 65 million years, with a focus on the most salient perturbation of the Cenozoic sulfur cycle, a 5‰ rise over a 15-million-year period in the early-middle Eocene. We discuss the possible causes suggested to date for the δ34Sswexcursion, which include changes in the magnitude, location, or fractionation associated with pyrite formation and burial, changes to the input of sulfate to the ocean, and changes in ocean circulation. We suggest how some new geochemical data and models can improve our understanding of the various Earth's surface processes that affect the global sulfur cycle and outline a framework for interpreting other geologic intervals where δ34Sswhas fluctuated.