Facies anatomy and early diagenesis of carbonate rocks

碳酸盐岩相解剖与早期成岩作用

• 批准号: RGPIN-2014-06454
• 负责人: James, Noel
• 金额: $ 5.25万
• 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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633763
• 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 the marine environment long ago tell us much about the very ancient oceans of our planet and thus the history of our world. The limestones are, furthermore, significant archives of the evolution of marine life through time, amongst the nation's most prolific hydrocarbon reservoirs deep underground, and critical aquifers for fresh water and so human wellbeing. The aim of the science proposed here is to understand 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 generate predictive scientific models that can be used by earth scientists to interpret ancient rocks at the earth’s surface or deeply buried underground. Specifically the focus is on the most poorly understood of these sediments and rocks specifically cool-water and high latitude marine carbonates and related deposits, the processes of early chemical alteration, both terrestrial and marine that change 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 carbonate deposition in the modern world. Expanding on previous NSERC-supported research in the region, the following questions will be addressed: 1) how is the composition of cool-water seafloor sediment related to the nature of the overlying seawater and how does this govern the chemistry of these deposits, 2) the same sediments are blown into spectacular marginal marine sand dunes and how does the composition these dunes reflect their source, the offshore marine environment, 3) do these offshore sediments somehow contribute to the formation of widespread marginal marine calcareous soils and what are the processes involved, and 4) what is the genesis of large marginal marine carbonate lakes under this semiarid climate adjacent to the Southern Ocean? These questions will be addressed via an integrated field program utilizing extensive onland mapping, and sampling and geochemical analysis, marine research, and computer modeling. Funds are also requested to investigate very ancient limestones, specifically 1) to understand how Paleozoic (550-225 million year old) marine carbonate sand bodies were formed and 2) to determine, via the nature of carbonate sedimentation, how the global ocean evolved during the Neoproterozoic (~800 million years ago) a period of global glaciation just before the evolution of complex animals. The end users of this research range from scientists such as paleontologists, paleoceanographers, and sedimentary geologists unraveling the rock record, to Canadian geoscientists searching for buried hydrocarbon reservoirs and mineral deposits to researchers monitoring marine environmental change.

石灰石等碳酸盐沉积岩主要由海洋化石制成。在很久以前，在海洋环境中形成的这些组成部分向我们讲述了我们地球上非常古老的海洋以及我们世界的历史。此外，石灰岩是海洋生物随着时间的演变的重要档案，在全国最多产的碳氢化合物储层中，地下深处，以及淡水的关键含水层以及如此人类的福祉。这里提出的科学的目的是了解当今海洋中的碳酸盐沉积物如何形成（相相解剖），以及如何在整个地质时期内将它们转化为岩石（早期成岩作用）。然后，这些发现被用来生成预测性科学模型，地球科学家可以将其用于解释地球表面上的古老岩石或深深埋葬地下。具体而言，重点是这些沉积物和岩石中最糟糕的理解，专门凉爽的水和高纬度海洋碳酸盐和相关的沉积物，早期化学变化的过程，陆地和海洋的变化，以及10亿年历史的前寒武纪碳酸盐的困扰，是在计划中的较大的碳水化合物。存入现代世界。扩大该地区的Nserc支持的研究，将解决以下问题：1）如何与上层海水的性质相关的凉水海底沉积物的组成以及如何控制这些沉积物的化学反应，2）相同的沉积物，相同的沉积物被吹入壮观的大型大洋砂丘陵和这些环境中，这些dunes的构成如何，以表现出3 nune的构图，以表现出来的三个dune，以表现出来离岸沉积物在某种程度上有助于形成宽度的边缘海洋钙质土壤，涉及什么过程，4）在与南部大洋相邻的半干旱气候下，大型边缘海洋碳酸盐湖的发生是什么？这些问题将通过广泛的Onland映射，采样和地球化学分析，海洋研究和计算机建模来解决这些问题。还要求资金调查非常古老的石灰石，特别是1）了解古生代（550-2.25亿年）如何形成碳酸盐砂体，以及2）通过碳酸盐沉积的性质，确定全球海洋在Neoperoteroterocic（约8亿年前）（约8亿年前的全球糖化动物时期）中如何演变。这项研究的最终用户范围从古生物学家，古汉库学家和沉积地质学家等科学家揭开岩石记录的繁殖地地质学家，再到寻找埋藏的碳氢化合物储层和矿物质的加拿大地球科学家，再到监测海洋环境变化的研究人员。