Sulfate and dolomitization - constraints for precipitation and alteration

硫酸盐和白云石化——降水和蚀变的制约因素

• 批准号: 319214793
• 负责人: Professor Dr. Harald Strauß
• 金额: --
• 依托单位: Institut für Geologie und Paläontologie
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/319214793?language=en
• 关键词: Sulfate; dolomitization; constraints; precipitation; alteration

Carbonate-associated sulfate is an important proxy in our quest for unraveling Earth evolution, specifically in respect to redox and its link to biological sulfur and carbon cycling. Consequently, a detailed understanding of the formation and diagenesis of carbonateassociated sulfate is a key prerequisite for successful research in Earth System Science. Despite its wide application in previous studies, uncertainties why, how, where and how much sulfate is incorporated during carbonate precipitation and retained during diagenesis still exist. A full mechanistic understanding of sulfate incorporation into carbonate (and changes during diagenesis) is particularly important for dolomites and variably dolomitized limestones that represent key lithologies in the Precambrian, yet numerous Phanerozoic examples exist as well. Even more so, as dolomite formation is intimately linked to the presence of sulfate in the environment and the activity of sulfate-reducing bacteria. Yet, a detailed is only emerging. This study aims at elucidating the intimate link between sulfate and dolomitization through Earth history. It centers on a clear differentiation between primary signatures and secondary, diagenetic features. Analysis of selected rock successions, ranging in age from the Archean to the present, will lead to a quantitative understanding how (in particular) the measured carbonate-associated sulfate abundance (but also the isotopic composition) in a carbonate rock relates back to ambient seawater sulfate concentration (and isotopic composition).

与碳酸盐相关的硫酸盐是我们探索地球演化的重要代表，特别是在氧化还原及其与生物硫和碳循环的联系方面。因此，详细了解碳酸盐伴生硫酸盐的形成和成岩作用是地球系统科学研究成功的关键先决条件。尽管硫酸盐在之前的研究中得到了广泛应用，但在碳酸盐沉淀过程中硫酸盐为何、如何、在何处以及有多少并入并在成岩作用过程中保留的不确定性仍然存在。对硫酸盐掺入碳酸盐（以及成岩过程中的变化）的完整机制了解对于代表前寒武纪关键岩性的白云岩和不同白云石化的石灰岩尤其重要，但也存在许多显生宙的例子。更重要的是，白云石的形成与环境中硫酸盐的存在以及硫酸盐还原菌的活性密切相关。然而，具体细节才刚刚浮现。这项研究旨在通过地球历史阐明硫酸盐和白云石化之间的密切联系。它的重点是主要特征和次要成岩特征之间的明显区别。对选定的岩石序列（从太古宙到现在的年龄范围）进行分析，将有助于定量了解（特别是）测量到的碳酸盐岩石中与碳酸盐相关的硫酸盐丰度（以及同位素组成）如何与周围海水相关硫酸盐浓度（和同位素组成）。