Collaborative Research: Geochemical Consequences of Extensive Gas Hydrate Formuation in Sediments of the Cascadia Accretionary Prism

为了量化从卡斯卡迪亚边缘水合物田到上覆水柱的流体和溶解成分的交换，设计了一个多研究者计划来测量卡斯卡迪亚地区各种条件下的这种交换。一个为期两年的实地项目将部署底栖生物设备，对流体排放进行取样。重力、推力和多岩心将用于评估大陆边缘沉积物中混合CH4-H2S水合物的近地表形成和分解如何影响底栖生物通量和早期成岩反应。第一年收集的数据将用于评估水合物田成分释放的空间变化，这些变化可能在活跃的喷口处最为显著。这些结果将1)确定在随后两次访问该地区期间进行时间变异性研究的理想地点，2)确定在以下实地计划中部署的时间长度和数量。在卡斯卡迪亚边缘存在的不同环境，以及时空实验设计将能够评估在卡斯卡迪亚边缘广泛存在的水合物形成对海底元素动员、运输和释放的影响。水合物地球化学在全球碳收支、气候变化模型、沉积物斜坡稳定性和能源问题中具有重要的相关性，因此这些知识在全球范围内具有更广泛的应用。

9731463 Brown To quantify the exchange of fluids and dissolved constituents from the Cascadia margin hydrate field to the overlying water column a multi-investigator program is designed to measure this exchange under a variety of conditions within the Cascadia region. A 2-year field program will deploy benthic devices that sample fluid discharge. Gravity, push and multicores will be used to assess how near-surface formation and decomposition of a mixed CH4-H2S hydrate in continental margin sediments influences benthic fluxes and early diagenetic reactions. The data collected during the first year will be used to assess the spatial variations of constituent release from the hydrate field, variations that are likely to be most significant at active venting sites. These results will 1) identify ideal sites for temporal variability studies to be conducted during two subsequent visits to the area, and 2) define the length and number of deployments in the following field programs. The different environments present in the Cascadia margin, along with the spatial-temporal experimental design will enable assessment of the effect of widespread hydrate formation in the Cascadia margin on element mobilization, transport, and release at the seafloor. This knowledge has applications for broader issues on a global scale, as hydrate geochemistry is of significant relevance in global carbon budgets, climate change models, sediment slope stability, and energy resource issues.