Carbonate sediments & natural organic matter

碳酸盐沉积物

• 批准号: 312463-2008
• 负责人: Neuweiler, Fritz
• 金额: $ 2.26万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=481279
• 关键词: Carbonate; sediments; natural; organic; matter

This research project explores the diagenesis of carbonate sediments in relation to both organisms that live near to the sediment surface and the non-living, natural organic matter that exudates into the interstitial environment during their degradation. The primary focus is to monitor the natural process of humification and how it influences, e.g., the formation of organic colloids and authigenic Ca-carbonates. Humification, next to photosynthesis, represents one of the most important transfer mechanisms of organic carbon on Earth. In general, it comprises the transformation of labile, biological macromolecules into geological macromolecules that are stable under the conditions of the Earth's surface. By consequence, and if certain conditions apply, such low-molecular weight humic compounds should be detectable even in geologically mature sedimentary rocks, hundreds of million of years in age. Recent insights from the analysis of modern and ancient sediments indicate that Phanerozoic, fine-grained carbonate mounds acted as a major sink of relatively fresh geopolymers. Humification, in concert with mineral authigenesis, not only offers an explanation for the accretion mechanism of these limestones, it also explains other geological features such as their fluorescence or the early opening of a cavity system. In the short term perspective, this project intends to substantiate our approach by exploring early diagenesis below the sponge bioherms of the Great Bahama Bank. The expected phenomena (calcification of sponge tissue, polycondensation, dissolution of opaline spicules, recrystallisation of aragonite) should serve as a paradigm for the ancient sponge-rich carbonate mounds. Such mounds were much more common in the geological past where they built up to form large structures. Prominent examples of ancient mounds, which I explore for comparison, occur in the Jurassic of the Atlas mountains in Morocco. However, the research interest there has a larger scope in that it also considers recovery from mass extinction, its impact on depositional geometries and the mobilisation of natural organic matter in the deep-burial environment. These issues are important for subsurface prognosis and exploration strategies for hydrocarbon reservoirs.

该研究项目探讨了碳酸盐沉积物与靠近沉积物表面的两种生物以及在降解过程中渗出到间质环境的非生命的自然有机物的成岩作用。主要的重点是监测嗡嗡声的自然过程及其影响，例如，有机胶体和身份质量CA碳酸盐的形成。在光合作用旁边，嗡嗡声代表了地球上有机碳最重要的转移机制之一。通常，它包括不稳定的生物大分子转化为地质大分子，这些分子在地球表面的条件下是稳定的。结果，如果某些条件适用，那么即使在地质成熟的沉积岩石中，也应检测到这种低分子量腐殖质化合物，即数百万年龄。对现代和古老沉积物分析的最新见解表明，植物学，细颗粒的碳酸盐土丘充当了相对新鲜的地球聚合物的主要水槽。与矿物的身份融合一起，嗡嗡声不仅为这些石灰石的积聚机理提供了解释，还解释了其他地质特征，例如它们的荧光或腔体系统的早期开放。从短期的角度来看，该项目打算通过在大巴哈马银行的海绵生物毛发下探索早期成岩作用来证实我们的方法。预期的现象（海绵组织的钙化，多头化，蛋白石spicules的溶解，后期的重结晶）应作为古代富含海绵的碳酸盐群的范式。在地质的过去，这些土墩更为普遍，它们建立以形成大型结构。我探索的古代土墩的重要例子发生在摩洛哥阿特拉斯山的侏罗纪。但是，该研究的范围更大，因为它还考虑了大规模灭绝的恢复，对沉积几何形状的影响以及在深层环境中动员天然有机物的影响。这些问题对于碳氢化合物的地下预后和勘探策略很重要。