The Fine-scale Hydrology and Geochemistry of the Areas of Active Venting Middle Valley, a Sedimented Rift on the Northern Juan de Fuca Ridge

朗塞特9417011这项研究计划涉及印第安纳大学、杜克大学和哥伦比亚大学的研究人员，计划详细调查胡安德富卡山脊附近活跃温泉附近的大量沉积环境中热液循环所涉及的过程，胡安德富卡山脊是一个位于俄勒冈州、华盛顿州和加拿大西部附近的洋脊扩张中心。为为期一个月的现场工作提出的具体计划包括研究沉积部分内的热、化学和流体传输以及这些沉积物的物理性质。获取这一详细的多组分数据集的目的是使用这三个相互依赖的组分来约束和定义流体路径和化学反应的模型，包括硫化物矿物在热喷口上方的泥土和岩石中的沉积。这个详细的项目之所以可能，部分是因为它使用了热流和孔隙水测量的尖端技术，这组研究人员在培育和使用这些技术方面发挥了重要作用。之前在两个拟议地点的研究包括由NSF赞助的海洋钻探计划船JOIDES Resolve进行的钻探，新数据允许按面积(根据沉积物上部20米的新测量结果)和深度(利用现有钻探数据和计划中的未来钻探数据，预计在1996-97年)进行外推，以定义循环和矿化的三维结构。除了提供对已知的产生大型矿化矿床的沉积温泉进行这种详细程度的第一次研究外，该项目还将为未来钻探的精确选址提供宝贵的数据。

Langseth 9417011 This research program, involving researchers from Indiana, Duke and Columbia Universities, proposes to investigate in detail the processes involved in circulation of hydrothermal fluids in a heavily sedimented setting adjacent to active hot springs on Juan de Fuca Ridge, a mid-ocean ridge spreading center located off Oregon, Washington and western Canada. The specific programs proposed for the one-month field effort include studies of heat, chemical and fluid transport within the sedimentary section and the physical properties of those sediments. The objective in acquiring this detailed, multicomponent data set is to use these three interdependent components to constrain and define models of the fluid pathways and chemical reactions, including the deposition of sulfide minerals within the mud and rock overlying the thermal vents. The detailed program is possible in part because it uses cutting edge technology for heat flow and pore water measurement, which this group of investigators has been instrumental in fostering and bringing to use. Previous study at the two proposed sites includes drilling by the NSF-sponsored Ocean Drilling Program vessel JOIDES Resolution, and the new data allows extrapolation of results both areally (with new measurements from the upper 20 meters of the sediments) and with depth (with existing drilling data and planned future drill data, which is expected in the 1996- 97 time frame) to define the 3-dimensional architecture of circulation and mineralization. In addition to providing the first study at this level of detail over sedimented hot springs known to produce large mineralized deposits, the program will provide valuable data for precise selection of sites for future drilling.