Collaborative Research: A Quantitative Study of Reaction Pathways in Oceanic Serpentinites

合作研究：大洋蛇纹岩反应途径的定量研究

• 批准号: 2214208
• 负责人: Thomas McCollom
• 金额: $ 26.12万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2214208&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantitative; Study; Reaction

The alteration of seafloor mantle rocks by seawater (referred to as serpentinization) is a widespread process. It affects global chemical cycles, earthquake potential, and possibly the origin of life. However, the process of serpentinization remains poorly understood. This work will conduct laboratory experiments to enable a better understanding of the underlying processes of serpentinization. The results will improve models and allow scientists to better interpret altered mantle rocks and fluid compositions. This project provides student training in geological oceanography, petrology, and aqueous geochemistry. To broaden participation in science, the researchers will involve undergraduate students from underrepresented minorities in this project. The students will be offered training in project design, sample analysis, data interpretation and presentation of results. Results of this project will be broadly disseminated through open access manuscripts, at international conferences, and workshops, and as well as through seminars, and teaching.It is hypothesized that distinct dissolution rates of minerals that constitute mantle rocks are decisive in controlling the fluxes of elements from the mantle rock and, therefore, in controlling the timing of secondary (hydrothermal) mineral formation events which dictate the temporal evolution of physical rock properties and compositions of vent fluids. To test this hypothesis, this work aims at systematically exploring the succession of chemical reactions recorded in altered mantle rocks by integrating chemical, isotopic, and quantitative mineralogical analyses with theoretical modeling. Chemical compositions, as well as mineralogical maps of partially altered mantle rocks will be used to reconstruct the original proportions of mantle minerals. By comparing mineral abundances of fresh and reacted rocks, relative dissolution rates and chemical fluxes will be inferred. To reconstruct the sequences of chemical reactions, abundances of minerals will be co-registered with the overall extents of alteration. Results from previous studies will be applied to determine the effect of temperature on the succession of dissolution-precipitation reactions. The analytical outcomes of this study will inform theoretical models that will take rock compositions, alteration temperature, surface areas, and distinct dissolution rates of minerals into account. By systematically varying the individual input parameters, these models will be developed that match the rock record. These models will then provide detailed insight on the evolution of fluid compositions associated with specific combinations of rock compositions, alteration temperatures, and mineral assemblages.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

海水对海底地幔岩的蚀变作用（称为蛇纹石化）是一个普遍的过程。它影响全球化学循环、地震可能性，甚至可能影响生命的起源。然而，对蛇纹岩化的过程仍然知之甚少。这项工作将进行实验室实验，以便更好地了解蛇纹岩化的基本过程。研究结果将改进模型，使科学家能够更好地解释蚀变地幔岩石和流体成分。该项目提供地质海洋学、岩石学和水地球化学方面的学生培训。为了扩大对科学的参与，研究人员将让来自代表性不足的少数民族的本科生参与这个项目。学生将接受项目设计、样品分析、数据解释和结果介绍方面的培训。该项目的成果将通过开放获取手稿、国际会议和研讨会以及研讨会和教学广泛传播。据推测，构成地幔岩的矿物的不同溶解速率在控制地幔岩中元素的通量方面具有决定性作用，因此，控制次生（热液）矿物形成事件的时间，这些事件决定了喷口流体的岩石物理性质和成分的时间演变。为了验证这一假设，这项工作的目的是系统地探索连续的化学反应记录在蚀变地幔岩石的化学，同位素和定量矿物学分析与理论建模相结合。部分蚀变地幔岩的化学成分和矿物学图将用于重建地幔矿物的原始比例。通过比较新鲜岩石和反应岩石的矿物丰度，可以推断出相对溶解速率和化学通量。为了重建化学反应的顺序，矿物的丰度将与蚀变的总体程度共同登记。从以前的研究结果将被应用到确定的溶解-沉淀反应的继承温度的影响。这项研究的分析结果将为理论模型提供信息，这些模型将考虑岩石成分，蚀变温度，表面积和矿物的不同溶解速率。通过系统地改变各个输入参数，将开发出与岩石记录相匹配的模型。这些模型将提供与岩石成分、蚀变温度和矿物组合的特定组合相关的流体成分演化的详细见解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。