Facies Anatomy and Early Diagenesis of Carbonate Rocks

碳酸盐岩的相解剖与早期成岩作用

• 批准号: RGPIN-2019-03994
• 负责人: James, Noel
• 金额: $ 2.19万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=737328
• 关键词: Facies; Anatomy; Early; Diagenesis; Carbonate

Carbonate sedimentary rocks such as limestone are largely made of marine fossils. These components that formed in ancient marine environments tell us much about the very ancient oceans on our planet and thus the history of our world. The limestones are, furthermore, significant archives of the evolution of marine life, amongst the nation's most prolific hydrocarbon reservoirs, and critical aquifers for fresh water and so human wellbeing. The aim of the science proposed here is to ascertain how marine carbonate sediments form in the ocean today (facies anatomy) and how they are then transformed into rock (early diagenesis) throughout the vastness of geologic time. These findings are then used to decipher global climate change and to generate predictive scientific models that can be used by earth scientists to interpret ancient rocks. The focus is on the most poorly understood of these sediments and rocks, specifically cool-water and high latitude polar marine carbonates and related deposits (heterozoan carbonates), the processes of early chemical alteration both terrestrial and marine that changed them, and the perplexing origin of 1 billion year old Precambrian carbonates. Much of the planned research will take place on and adjacent to the southern Australian continental shelf, the largest area of cool-water, heterozoan, carbonate deposition in the modern world. Expanding on previous NSERC-supported research in the region, specific questions will be addressed via an integrated field program utilizing extensive onland mapping, sampling, and geochemical analysis, marine research, and computer modeling. Research will focus on shallow marine, marginal marine, and lacustrine depositional systems. Funds are also requested to investigate very ancient limestones, specifically 1) to understand how late Devonian (~380 million year old) warm-water (photozoan) reefs formed just prior to a global extinction event, and 2) to determine, via the nature of carbonate sedimentation, how the global ocean evolved during the Neoproterozoic (~800 million years ago) just before the evolution of complex animals. Highly Qualified Personnel (HQP) are an integral part of this science. Graduate and undergraduate students are involved in all aspects of the research both in the field (land and marine) and in the laboratory (petrography and geochemistry). They present their results at scientific meetings and are authors on resulting scientific papers. End users of this research are those scientists that research ancient carbonate rocks. Paleontologists, paleoceanographers, and sedimentary geologists utilize the information to unravel the rock record. Canadian geoscientists using comparative reasoning to search for and exploit hydrocarbon reservoirs and mineral deposits, together with researchers monitoring marine environmental change through time must be familiar with details of deposition and early diagenesis to be successful.

石灰岩等碳酸盐沉积岩主要由海洋化石组成。这些在古代海洋环境中形成的成分告诉我们很多关于我们星球上非常古老的海洋的信息，从而告诉我们世界的历史。此外，石灰岩是海洋生物进化的重要档案，是美国最多产的碳氢化合物储层，也是淡水和人类福祉的关键含水层。这里提出的科学目的是确定海洋碳酸盐沉积物如何在当今的海洋中形成（相解剖学）以及它们如何在漫长的地质时期转化为岩石（早期成岩作用）。这些发现随后被用来解读全球气候变化，并生成预测科学模型，地球科学家可以使用这些模型来解释古代岩石。重点是人们对这些沉积物和岩石知之甚少，特别是冷水和高纬度极地海洋碳酸盐及相关沉积物（杂动物碳酸盐）、改变它们的陆地和海洋早期化学蚀变过程，以及令人费解的起源10 亿年前的前寒武纪碳酸盐岩。计划中的大部分研究将在澳大利亚南部大陆架及其附近进行，这里是现代世界最大的冷水、杂动物、碳酸盐沉积区。扩展先前 NSERC 支持的该地区研究，具体问题将通过利用广泛的陆地测绘、采样和地球化学分析、海洋研究和计算机建模的综合实地计划来解决。研究将集中于浅海、边缘海和湖泊沉积系统。还需要资金来调查非常古老的石灰岩，特别是 1) 了解晚泥盆世（约 3.8 亿年前）温水（光生物）珊瑚礁是如何在全球灭绝事件之前形成的，2) 通过大自然来确定碳酸盐沉积作用，了解全球海洋在复杂动物进化之前的新元古代（约 8 亿年前）如何演化。 高素质人员 (HQP) 是这门科学的一个组成部分。研究生和本科生参与实地（陆地和海洋）和实验室（岩相学和地球化学）研究的各个方面。他们在科学会议上展示他们的研究结果，并成为科学论文的作者。 这项研究的最终用户是那些研究古代碳酸盐岩的科学家。古生物学家、古海洋学家和沉积地质学家利用这些信息来解开岩石记录。加拿大地球科学家使用比较推理来寻找和开采碳氢化合物储层和矿藏，以及监测海洋环境随时间变化的研究人员，必须熟悉沉积和早期成岩作用的细节才能取得成功。