Quantifying the Volume Changes During Serpentinization of Peridotite using Hydrothermal Laboratory Experiments and X-ray Microtomography

使用热液实验室实验和 X 射线显微断层扫描量化橄榄岩蛇纹石化过程中的体积变化

• 批准号: 1551431
• 负责人: Frieder Klein
• 金额: $ 35万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1551431&HistoricalAwards=false
• 关键词: Quantifying; Volume; Changes; During; Serpentinization

The interaction of mantle rocks with aqueous fluids (i.e. serpentinization) is a widespread hydrothermal process associated with tectonic plate boundaries. By adding significant amounts of water to mantle rocks, serpentinization causes a decrease in rock density and mechanical strength. As a result serpentinization is believed to play a major role in the formation and breakup of continents, seafloor spreading and subduction. The hydration of mantle rocks impacts the global geochemical cycles of volatiles, most notably water and carbon dioxide, with strong implications for Earth's climate, mantle melting in volcanic arcs and the seismicity of subduction zones. Serpentinization has operated throughout most of Earth's history and has, via the production of hydrogen, created geochemical conditions capable of supporting microbial life in extreme subsurface environments. Despite its key role in a number of global geological processes, the most basic relations between chemical mass transfer during serpentinization and associated changes in rock volume have remained poorly quantified. This project is designed to improve our understanding of these processes. The overall objective of this research is to link changes in fluid composition and mineralogy to concomitant changes in volume as a function of time and temperature using a combination of hydrothermal laboratory experiments, mineral and fluid analysis, X-ray microtomography (µ-CT), and geochemical modeling. In particular this project will resolve whether serpentinization can be regarded as an isochemical or an isovolumetric process, a long-standing and strongly debated question in serpentinization research. The results of this study will have important ramifications for our understanding of the geochemistry, emplacement and deformation of serpentinite in a wide range of geological settings.

地幔岩石与水相流体的相互作用（即蛇纹石化）是与构造板块边界相关的广泛的热液过程，通过向地幔岩石中添加大量的水，蛇纹石化会导致岩石密度和机械强度降低。在大陆的形成和分裂、海底扩张和俯冲中发挥重要作用地幔岩石的水合作用影响着全球挥发物的地球化学循环，其中最引人注目的是。水和二氧化碳对地球气候、火山弧地幔融化和俯冲带的地震活动产生了重大影响，蛇纹石化作用贯穿了地球历史的大部分时间，并通过产生氢气创造了能够支持微生物生命的地球化学条件。尽管其在许多全球地质过程中发挥着关键作用，但蛇纹石化过程中的化学传质与岩石体积的相关变化之间最基本的关系仍然缺乏量化。旨在提高我们对这些过程的理解，这项研究的总体目标是结合热液实验室实验、矿物和流体分析，将流体成分和矿物学的变化与随时间和温度变化的体积变化联系起来。特别是，该项目将有力地解决蛇纹石化过程是否可以被视为等化学过程或等体积过程，这是蛇纹石化过程中长期存在且有争议的问题。这项研究的结果将对我们了解各种地质环境中蛇纹岩的地球化学、就位和变形产生重要影响。

项目成果

Quantifying the volume increase and chemical exchange during serpentinization

量化蛇纹石化过程中的体积增加和化学交换

• DOI: 10.1130/g47289.1
• 发表时间: 2020
• 期刊: Geology
• 影响因子: 5.8
• 作者: Klein, F;LeRoux, V
• 通讯作者: LeRoux, V