Mobility and Storage of Volatiles in Forearcs: The Metamorphic Record

[9805050]本研究将考察深层沉积岩石中挥发性组分的脱挥发或保留程度作为深部P-T历史的函数弧前。这种综合的野外、岩石学和地球化学工作将集中在以前详细的岩石学和热年代学研究为顺行和逆行变质演化提供限制的地层上，并将集中在俯冲旋回预计很重要的选定的挥发组分上。不同程度挥发性损失的证据将与现在的矿物学和推断的进变质反应历史联系起来。该研究还将提供有关低T、高p /T变质套保存高p /T流体同位素组成和来源记录的程度、深部孔隙水俯冲的程度以及前弧深部流体可动性尺度的信息。油田将包括西巴哈地层和弗兰西斯坎复合体的部分地区。第二项任务将在海岸山脉的选定曝光中进行研究。

9805050 Bebout This research will examine the extents of devolatilization or retention of volatile components in deeply accreted rocks as functions of P-T history deep in forearcs. This integrated field, petrologic and geochemical work will concentrate on suites for which previous detailed petrologic and thermochronological studies have provided constraints on prograde and retrograde metamoprhic evolution, and will focus on selected voaltile components for which subduction cycling is expected to be important. The evidence for varying degrees of volatile loss will be linked with present mineraology and inferred prograde metamorphic reaction histories. The reserach will also provide information regarding the degree to which low-T, high-P/T metamorphic suites preserve a record of the isotopic compositions and sources of high-P/T fluids, the extents of deep pore water subduction, and the scales of fluid mobility at depth in forearcs. The field areas will include the Western Baja Terrane and parts of the Fransciscan Complex. The second task will be studied in selected exposures in the Coast Ranges.