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，主要是由海洋化石构成的。这些在古代海洋环境中形成的成分告诉了我们很多关于地球上非常古老的海洋的信息，从而也告诉了我们这个世界的历史。此外，石灰石是海洋生物进化的重要档案，是全国最丰富的碳氢化合物储层之一，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海洋碳酸盐沉积物是如何在今天的海洋中形成的（相解剖学），以及它们是如何在漫长的地质年代中转化为岩石的（早期成岩作用）。然后，这些发现被用来破译全球气候变化，并产生可被地球科学家用来解释古代岩石的预测科学模型。研究的重点是对这些沉积物和岩石最不了解的部分，特别是冷水和高纬度极地海洋碳酸盐和相关沉积物（异动物碳酸盐），早期陆地和海洋化学变化的过程，以及10亿年前前寒武纪碳酸盐的令人困惑的起源。