Elemental and Isotopic Systematics in Erosional and Accretionary Subduction Zones, with Implications for Fluid Sources, Pathways, and Fluxes

侵蚀和增生俯冲带的元素和同位素系统学，对流体源、路径和通量的影响

• 批准号: 1153870
• 负责人: Miriam Kastner
• 金额: $ 43万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-15 至 2018-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1153870&HistoricalAwards=false
• 关键词: Elemental; Isotopic; Systematics; Erosional; Accretionary

Tectonic plate boundaries where ocean crust subducts beneath continental crust are associated not only in the Earth's most active earthquake zones, but also with the largest concentration of land volcanoes. Our understanding of these areas (also called subduction zones) and the processes that cause associated seismic and volcanic hazards is therefore needed for us to be able to better protect coastal communities and prepare effective land use and hazard mitigation strategies. Because both volcanism and earthquakes are affected by, and many times triggered by, fluids and the dehydration of minerals exposed to increasing temperatures and pressures as subduction occurs, our knowledge of how subduction zone fluids change with space, time, and composition across and between subduction zones is critical to our understanding of how these important areas behave and evolve over time. This research completes the geochemical data sets of subduction zones off the northwestern US, Japan, South and Central America, and the Caribbean. It also compiles all relevant laboratory experimental data, pore fluid, and deep sea bore hole fluid data with a focus on synthesizing this voluminous dataset and seeking new insights into how the geochemistry of fluids can reveal processes occurring at depth in the subduction process. Where identified, gaps in the geochemical record of these fluids will be completed, including creating an isotopic dataset for oxygen, deuterium, strontium, lithium, boron. The collective data will be used to examine mass balances of elements, the contribution of subduction fluids to the make-up of present day seawater, the role of compaction and dehydration/hydration reaction on fluid chemistry, and insights on the evolution of pore fluid pressures. Broader impacts of the work include support of a more than 15 year NSF investment in subduction zone characterization and dynamics and support of a PI whose gender is under-represented in the sciences.

海洋地壳俯冲到大陆地壳之下的构造板块边界不仅与地球最活跃的地震带有关，而且与陆地火山最集中的地区有关。 因此，我们需要了解这些区域（也称为俯冲带）以及导致相关地震和火山灾害的过程，以便能够更好地保护沿海社区并制定有效的土地利用和减灾战略。 由于火山活动和地震都受到俯冲时暴露在不断升高的温度和压力下的流体和矿物脱水的影响，并且多次由其引发，因此我们对俯冲带流体如何随俯冲过程中的空间、时间和成分变化的了解区域对于我们理解这些重要区域如何随着时间的推移而表现和演变至关重要。 这项研究完成了美国西北部、日本、南美洲和中美洲以及加勒比海俯冲带的地球化学数据集。 它还汇编了所有相关的实验室实验数据、孔隙流体和深海钻孔流体数据，重点是综合这一庞大的数据集，并寻求关于流体地球化学如何揭示俯冲过程中深度发生的过程的新见解。 一旦确定，这些流体的地球化学记录中的空白将被填补，包括创建氧、氘、锶、锂、硼的同位素数据集。 收集的数据将用于检查元素的质量平衡、俯冲流体对当今海水构成的贡献、压实和脱水/水合反应对流体化学的作用，以及对孔隙流体压力演变的见解。 这项工作的更广泛影响包括支持 NSF 对俯冲带特征和动力学超过 15 年的投资，以及支持性别在科学中代表性不足的 PI。