Characterization of Herringbone Calcite from an Eocene Carbonate Platform, Egypt

9972994Sumner人字形方解石是一种独特的方解石水泥，具有宏观带状和特定的晶体学性质，其独特的形态可能源于沉淀溶液中Fe2+或Mn2+的存在。在埃及中始新世碳酸盐岩台地的裂缝和洞穴中发现了保存极为完好的人字方解石，这将为测试先前提出的基于太古宙海洋事件的人字方解石降水模型提供机会。如果能够限制促进人字方解石沉淀的条件，就可以更好地了解古代海洋化学，并且结果将有助于深入了解控制方解石晶体形态的基本过程。因此，本项目的研究目标是对埃及人字方解石的形态和地球化学特征进行表征，并利用这些结果来约束促进人字方解石晶体结构发育的条件。

9972994Sumner Herringbone calcite, a distinctive calcite cement with macroscopic banding and specific crystallographic properties, may derive its distinctive morphology from the presence of Fe2+ or Mn2+ in the precipitating solution. Extremely well preserved herringbone calcite present in fissures and caves in a Middle Eocene carbonate platform, Egypt, will provide the opportunity to test previously proposed models for herringbone calcite precipitation based on Archean marine occurrences. If the conditions promoting herringbone calcite precipitation can be constrained, a better understanding of ancient ocean chemistry can be developed, and results will lead to insights into the fundamental processes controlling calcite crystal morphology. Thus, the research objectives for this project are to morphologically and geochemically characterize the Egyptian herringbonecalcite, and to use the results to constrain conditions promoting development of the herringbone calcite crystal texture.