Molekulare Fossilien: Schlüssel zum Ursprung diagenetischer Karbonatkonkretionen

分子化石：成岩碳酸盐结核起源的关键

• 批准号: 389337055
• 负责人: Professor Dr. Volker Thiel
• 金额: --
• 依托单位: Institut für Mikrobiologie und Genetik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/389337055?language=en
• 关键词: Molekulare; Fossilien; Schl; ssel; zum

Diagenetic carbonate concretions commonly form during shallow burial via localized lithification of soft sediment and have long been recognized as a source of exceptionally preserved fossils. While concretions are common in many ancient sediments, modern equivalents are very rare and our understanding of the complex biogeochemical processes underlying their formation is incomplete. In this project the organic matter enclosed in ancient concretions is studied with organic geochemical techniques to provide further clues to the formation of these precipitates and test their significance as containers of exceptionally preserved molecular fossils. It is proposed that lipid biomarkers and kerogen locked in concretions may represent a "snapshot" of the original sedimentary OM, plus the early microbial processes as they once occurred in the freshly deposited sediment. A particular focus is placed on testing the role of Ca- and or Mg-salts of carboxylic acids (particularly fatty acids, "adipocere"), and their anaerobic degradation products as raw materials for the formation of carbonate concretions. For this purpose, ancient (Early Jurassic) carbonate concretions from Buttenheim (Bavaria) and Hondelage (Lower Saxony) will be studied in relation to their immediate host rocks using extract based (GC-MS, IRM-GC-MS) and pyrolysis techniques (Hypy; Py-GC-MS).

成岩碳酸盐结核通常在浅埋过程中通过软沉积物的局部岩化形成，长期以来一直被认为是保存完好的化石的来源。虽然结核在许多古代沉积物中很常见，但现代的类似物非常罕见，而且我们对其形成背后的复杂生物地球化学过程的理解并不完整。在该项目中，利用有机地球化学技术研究了古代结核中包裹的有机物，以提供这些沉淀物形成的进一步线索，并测试它们作为保存完好的分子化石容器的重要性。有人提出，锁定在结核中的脂质生物标志物和干酪根可能代表原始沉积物有机质的“快照”，加上它们曾经在新沉积的沉积物中发生的早期微生物过程。特别重点是测试羧酸的钙盐和/或镁盐（特别是脂肪酸，“脂肪蜡”）及其厌氧降解产物作为形成碳酸盐结核的原材料的作用。为此，将使用提取物（GC-MS、IRM-GC-MS）和热解技术，研究来自 Buttenheim（巴伐利亚）和 Hondelage（下萨克森）的古代（早侏罗世）碳酸盐结核与其直接母岩的关系。 Hypy-GC-MS)；