IODP Expeditions 334/344 Objective Research: Geochemical investigation of fluid/rock reactions and the nature of fluid flow at the erosive Costa Rica subduction zone

这项提议试图描述哥斯达黎加俯冲带上几个地点的流体化学特征。将分析流体中的硅、硼、溴、氟、18O、氚、11B和7Li。这些信息将被用来确定流体来源的温度，并限制产生流体的低级变质/成岩反应。这些反应可能对板块边界断层的粘滑行为有影响。这项工作代表了描述沿侵蚀俯冲带的流体流动和断层行为的努力的一部分，是对目前在日本近海的吸积俯冲带所做工作的补充。这项工作对于完成IODP探险334和344的目标至关重要。更广泛的影响包括更好地了解可能引发大地震和可能发生海啸的断层。一名研究生将参加一项国际合作，包括前往台湾的一个实验室并在那里工作。该项目还涉及本科生，包括一篇高级论文，将结果纳入本科生班级，并在专门为吸引代表不足群体的人进入科学领域而设计的会议上展示结果。

This proposal seeks to characterize fluid chemistry at several sites across the Costa Rica subduction zone. Fluids will be analyzed for Si, B, Br, F, 18O, deuterium, 11B and 7Li. This information will be used to determine the temperatures of the fluid sources and constrain the low-grade metamorphic/diagenetic reactions that produce the fluids. These reactions may have implications for stick-slip behavior along the plate boundary fault. This work represents part of an effort to characterize the fluid flow and faulting behavior along an erosive subduction zone and is complementary to work currently being done on an accretionary subduction zone off of Japan. The work is critical to the completion of the objectives of IODP expeditions 334 and 344.Broader impacts include a better understanding of fault with the potential to produce large earthquakes and, possibly, tsunamis. A graduate student will be taking part in an international collaboration, including travel to and work in a laboratory in Taiwan. The project also involves undergraduate students, including a senior thesis, incorporation of results into undergraduate classes, and presentation of results to a conference specifically designed to attract persons from under-represented groups to science.