Kinetic and Thermodynamic Controls on Mg and Sr Contents during Calcite Growth: Establishing a Baseline for Biological Mineralization

方解石生长过程中镁和锶含量的动力学和热力学控制：建立生物矿化的基线

• 批准号: 0083173
• 负责人: Patricia Dove
• 金额: $ 30.01万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-12-15 至 2004-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0083173&HistoricalAwards=false
• 关键词: Kinetic; Thermodynamic; Controls; Mg; Sr

Trace elements, especially those that may be used as paleoproxies, behave as lattice impurities that regulate biomineralization and provide critical information on crystal growth history. For example, incorporation of Mg2+ has been shown to modify the morphology, solubility and polymorphic expression of CaCO3 biominerals. In addition, Mg2+ is the principal inhibitor of calcite growth in natural waters, thereby influencing the size and reactivity of the biogeochemically significant carbonate reservoir. However, the fundamental mechanistic interactions of Mg2+ with calcite surfaces remain controversial. For this reason, the PI will use an experimental approach that integrates techniques from aqueous geochemistry and surface sciences to quantify the kinetic and thermodynamic controls on Mg and Sr contents of calcite grown in 0.1 M NaCl and synthetic seawater solutions. The PI also will determine the mechanism(s) by which Mg and Sr modify calcite growth properties and morphology and construct a quantitative and mechanistic model of calcite growth that provides a baseline for understanding the complexity of the influences of biological processes on the elemental composition of carbonate minerals. Results from this research will provide a baseline for understanding the influence of trace elements incorporated into calcite. This information is needed to interpret the compositions of biogenic calcite and in understanding paleotemperature data.

微量元素，特别是那些可能被用作古代用品的元素，作为晶格杂质，调节生物矿化作用，并提供晶体生长历史的关键信息。 例如，Mg2+的掺入已被证明可以改变CaCO3生物矿物的形态、溶解度和多晶型表达。 此外，Mg 2+是天然沃茨中方解石生长的主要抑制剂，从而影响地球化学意义重大的碳酸盐岩储层的大小和反应性。 然而，Mg 2+与方解石表面的基本机制相互作用仍然存在争议。 出于这个原因，PI将使用一种实验方法，该方法集成了水地球化学和表面科学技术，以量化在0.1 M NaCl和合成海水溶液中生长的方解石中Mg和Sr含量的动力学和热力学控制。 PI还将确定Mg和Sr改变方解石生长特性和形态的机制，并构建方解石生长的定量和机理模型，为理解生物过程对碳酸盐矿物元素组成的影响的复杂性提供基线。 这项研究的结果将为了解方解石中微量元素的影响提供一个基线。 这些信息是解释生物成因方解石的组成和了解古温度数据所必需的。