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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=714540
• 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.

碳酸盐沉积岩，如石灰岩，主要由海相化石组成。这些在古代海洋环境中形成的组件告诉了我们许多关于我们星球上非常古老的海洋的信息，从而也告诉了我们世界的历史。此外，这些石灰岩是海洋生物进化的重要档案，是美国最丰富的碳氢化合物储集层之一，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今天海洋碳酸盐沉积物是如何在海洋中形成的(相解剖)，以及它们是如何在漫长的地质年代中转化为岩石(早期成岩作用)的。然后，这些发现被用来破译全球气候变化，并产生可供地球科学家用来解释古代岩石的预测性科学模型。重点是这些沉积物和岩石中最鲜为人知的，特别是冷水和高纬度极地海相碳酸盐和相关沉积(杂生孢子碳酸盐)，改变它们的早期陆地和海洋化学变化过程，以及10亿年前寒武纪碳酸盐令人困惑的起源。 计划中的大部分研究将在南澳大利亚大陆架及其邻近地区进行，这是现代世界最大的冷水、杂虫和碳酸盐沉积区域。在NSERC以前在该地区支持的研究的基础上，具体问题将通过一个综合的现场计划来解决，该计划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。研究将集中在浅海、边缘海和湖相沉积体系。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)暖水(光生动物)礁是如何在全球物种灭绝事件之前形成的，以及2)通过碳酸盐沉积的性质确定全球海洋在新元古代(约8亿年前)就在复杂动物进化之前是如何演变的。 高素质人才(HQP)是这门科学不可分割的一部分。研究生和本科生在实地(陆地和海洋)和实验室(岩石学和地球化学)参与研究的方方面面。他们在科学会议上展示他们的成果，也是由此产生的科学论文的作者。 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发碳氢化合物储集层和矿藏，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成功。