Hydrothermal Systems in the Eastern Manus Basin: Fluid Chemistry and Magnetic Structure as Guides to Subseafloor Processes

PIs计划对PACMANUS热液区进行高分辨率的近底测深、磁测和采样计划，并在马努斯盆地东部（EMB）的PACMANUS和Desmos热液系统中收集和分析流体、固体样品和地球物理数据。他们的目标是将Leg 193钻芯数据与综合的化学、矿物、同位素和地球物理数据相结合，以识别和约束影响地壳蚀变、流体化学、沉积物组成和形态的关键变量，以及在含硅岩系统中生物群落可用的栖息地范围。我们的想法是研究整个系统，包括深度的蚀变组合。具体目标是：1)圈定东缘英质地壳内热液活动的构造和构造控制；2)研究了热液流体与长英岩（英安岩-流纹英岩）组成的岩石的相互作用，这些岩石代表了基底组成谱中的一个端元；3)约束成矿的地球化学过程；4)评价岩浆流体在EMB热液系统中的作用。

The PIs propose to conduct a high-resolution near-bottom bathymetric and magnetic survey and sampling program of the PACMANUS hydrothermal area and to collect and analyze fluid and solid samples and geophysical data from PACMANUS and Desmos hydrothermal systems in the eastern Manus Basin (EMB). Their goal is to integrate Leg 193 drill core data with comprehensive chemical, mineral, isotopic, and geophysical data to identify and constrain the key variables that influence crustal alteration, fluid chemistry, deposit composition and morphology, and the range of habitats available for biological communities in felsic-rock hosted systems. The idea is to study the entire system, including alteration assemblages at depth. Specific goals are to 1) delineate the tectonic and structural controls on hydrothermal activity within felsic crust of the EMB; 2) examine interaction of hydrothermal fluids with rocks of felsic composition (dacite to rhyodacite), which represent an endmember in the spectrum of basement compositions; 3) constrain geochemical processes responsible for ore formation; and 4) assess the role of magmatic fluids in EMB hydrothermal systems.