Formation of fossiliferous concretions in the Cretaceous Santana Formation - Assessing the role of microbial processes

白垩纪桑塔纳地层中含化石结核的形成 - 评估微生物过程的作用

• 批准号: 120611663
• 负责人: Professor Dr. Ulrich Heimhofer
• 金额: --
• 依托单位: Institut für Geologie, Mineralogie und Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/120611663?language=en
• 关键词: Formation; fossiliferous; concretions; Cretaceous; Santana

Exceptional fossil preservation (incl. soft-tissue phosphatization) within organic-rich black shales is often associated with the formation of a protective carbonate shell surrounding the fossil specimen. Whereas the mechanisms controlling soft-tissue mineralization during the earliest stage of fossilization are considerably well understood, only limited information is currently available on the complex biogeochemical processes which lead to the precipitation of the concretionary carbonate body around the fossils. The proposed pilot study will focus on the organic and inorganic geochemistry of carbonate concretions derived from black shale deposits of the Early Cretaceous Santana Formation (Araripe Basin, NE Brazil). This konservat-type fossil lagerstätte is world famous for its fossiliferous concretions hosting an exceptionally preserved fish and reptile fauna. The principle aim of this study is twofold including (1) identification of the type and source of organic matter trapped within the Santana concretions and (2) assessment of the different microbial or microbially-mediated processes associated with successive concretion growth during early burial. The achievement of these goals is expected from the combination of organic molecular geochemistry (incl. compound-specific δ13C analytics) with high-resolution inorganic geochemistry and sedimentary petrography.

在富含有机物的黑色页岩中，特殊的化石保存（包括软组织磷化）通常与化石标本周围保护性碳酸盐壳的形成有关。虽然在石化早期控制软组织矿化的机制已经相当清楚，但目前关于导致化石周围凝结碳酸盐体沉淀的复杂生物地球化学过程的信息有限。拟议的试点研究将侧重于早白垩世Santana组（巴西东北部Araripe盆地）黑色页岩沉积物中碳酸盐结核的有机和无机地球化学。这个保护区类型的化石lagerstätte以其保存完好的鱼类和爬行动物的化石凝结而闻名于世。本研究的主要目的有两个：(1)确定桑塔纳结核中捕获的有机质的类型和来源；(2)评估早期埋藏期间与连续结核生长相关的不同微生物或微生物介导的过程。有机分子地球化学（包括化合物特异性δ13C分析）与高分辨率无机地球化学和沉积岩石学相结合，有望实现这些目标。