SGER: Changes in vent fluid chloride and volatile content as a result of the 2006 eruption at 9N, EPR

知识价值：本提案要求资助参加两次巡游所产生的费用，以建立一个基线数据集，以了解与东太平洋隆起脊2000综合研究地点热液系统最近的火山喷发有关的化学变化。首次巡查于2006年6月进行，初步数据显示，自2004年11月最近一次巡查以来，气体浓度发生了显著变化。此外，在2006年6月的巡航中，在375℃的通风口中放置了一个能够间隔30秒测量氯化物浓度的电阻率仪器。通过监测排液中氯含量的变化，可以对水岩反应体系中发生的相分离程度和性质的时间变化进行限制。这为热液蚀变提供了重要的控制，因为氯化物在决定矿物溶解度方面起着重要作用。这台仪器将于2006年11月回收，另外两台仪器将部署一年。2006年11月还将收集大约50个流体样本，提取气体含量并送回实验室进行浓度和同位素分析。在火山喷发后尽快收集到的这些数据将有助于了解岩浆扰动下热液系统的整体行为。更广泛的影响：本研究是多学科跨机构合作的一部分。该项目将直接解决NSF Ridge 2000项目中关于岩浆作用与海洋化学以及支持化学合成初级生产者的极端微生物生物圈的地球化学环境的关系的关键问题。

Intellectual Merit: This proposal requests funding to cover the costs incurred in participating in two cruises to establish a baseline data set for understanding the changing chemistry associated with the recent volcanic eruption at the 9 N East Pacific Rise Ridge 2000 Integrated Studies Site hydrothermal system. The initial cruise took place in June 2006 and resulted in initial volatile data that indicated significant changes in gas concentrations since the latest prior visit to the site in November, 2004. In addition, a resistivity instrument capable of measuring chloride concentrations on a 30 sec interval was placed in a 375 C vent during the June 2006 cruise. By monitoring changes in chlorinity of vent fluids, constraints are placed on time-changes in the degree and nature of phase separation that occurs within the water-rock reaction system. This provides important controls on hydrothermal alteration, since chloride has an important role in determining mieral solubility. This instrument will be recovered in November 2006 and two additional instruments will be deployed for one year duration. On the order of fifty fluid samples will also be collected in November 2006, the gas contents extracted and returned to the laboratory for concentration and isotopic analyses. These data collected as soon as possible after the eruption will be of great use in helping to understand the overall behavior of the hydrothermal system to a magmatic perturbation. Broader Impacts: This research is part of a multi-disciplinary inter-institutional collaboration. This project will directly address key questions from the NSF Ridge 2000 program concerning the relationship of magmatism to ocean chemistry and to the geochemical environment that supports an extremophilic biosphere of chemosynthetic primary producers.