Isotope effects in carbonate minerals: Proxies for environmental changes and biosignatures

方解石和文石等碳酸盐是地球表面最丰富的矿物之一。由于其天然的普遍存在，这些碳酸盐矿物经常成为物理、化学和地质研究的对象。特别是，地球科学家和古气候学家长期以来一直使用海洋和大陆碳酸盐的地球化学性质来破译地球过去的环境变化，为开发能够预测未来气候的准确气候模型提供古环境记录。例如，珊瑚、洞穴沉积物、鱼耳骨和海洋浮游生物贝壳在古气候学和古海洋学领域都是无价的碳酸盐气候档案。在探索奖助金计划的资助下，我的研究小组将根据实验室生长的碳酸盐的生长条件，对其多种地球化学性质进行表征。然后将确定这些环境敏感的地球化学特征的机制，建立开发新的创新的地球化学工具的理论基线，以更好地提取过去的环境变化以及在碳酸盐矿物形成时记录的生物活动的指纹。*我的研究计划的长期目标是(1)努力彻底了解在各种碳酸盐-水系统中观察到的同位素效应，从而(2)开发一个统一的模型，通过该模型可以在实验室或野外的实验和/或观测研究的基础上预测这些物理化学过程。为了实现这些研究目标，我的研究小组将利用我最先进的研究设施进行一系列实验室实验，旨在接近模拟天然碳酸盐的生长条件。随后，我们将仔细监测这些合成碳酸盐中多种元素(如硼、钙、碳、锂、镁、氧和块状同位素)随着不同形成条件和生物活性的变化。我的研究计划的结果将为我们的社区提供更可靠的科学工具，以重建地球的环境历史，并预测未来的气候变化。这种预测未来短期和长期气候变化的能力将使政策制定者能够及时制定相关的政府政策和法规，确保加拿大居民获得许多潜在的社会、文化和经济利益。此外，我们的研究成果还将允许在许多其他科学领域使用碳酸盐矿物，如天体生物学，其中碳酸盐矿物可以用来确定来自外星物质的潜在生物特征。

Carbonates such as calcite and aragonite are among the most abundant minerals on the surface of the Earth. Due to their natural ubiquity, these carbonate minerals have frequently been the subject of physical, chemical, and geological studies. In particular, Earth scientists and paleoclimatologists have long used the geochemical properties of marine and continental carbonates to decipher Earth's past environmental variations, providing paleoenvironmental records for the development of accurate climate models that are capable of future climate prediction. For example, corals, cave deposits, fish ear-bones, and shells of marine plankton have been invaluable carbonate climate archives in the fields of paleoclimatology and paleoceanography. With the financial assistance of the Discovery Grants program, my research group will characterize multiple geochemical properties of laboratory-grown carbonates depending on their growth conditions. The mechanisms of these environment-sensitive geochemical signatures will then be identified, establishing theoretical baselines to develop new innovative geochemical tools to better extract the past environmental changes, as well as the fingerprints of biological activities recorded in carbonate minerals when they formed.*******The long-term goals of my research program are (1) to work toward a thorough understanding of the isotope effects observed in various carbonate-water systems, and thus (2) to develop a unifying model by which these physicochemical processes can be predicted on the basis of experimental and/or observational studies in the laboratory or in the field. To achieve these research goals, my research group will perform a series of laboratory experiments designed to closely mimic the growth conditions of natural carbonates using my state-of-the-art research facilities. Subsequently, we will carefully monitor the isotopic variations of multiple elements (e.g., boron, calcium, carbon, lithium, magnesium, oxygen, and clumped isotopes) in these synthetic carbonates as a function of different formational conditions and biological activities. The outcome of my research program will provide our community with more reliable scientific tools to reconstruct Earth's environmental history and also to predict future climate changes. This ability to forecast short- and long-term future climate variability will allow policymakers to prepare relevant government policies and regulations in a timely manner, ensuring many potential social, cultural, and economical benefits to the residents of Canada. Furthermore, our research outcome will also allow the use of carbonate minerals in many other fields of science, such as astrobiology where carbonate minerals could be used to determine potential biosignatures from extra-terrestrial materials.***