Deep-crustal Reactive Fluid Flow in the Mesozoic White-Inyo Magmatic Arc, California

水，除了明显地存在于地球表面？S，也是大陆深部地壳不可分割的一部分。在地壳中，水在结构上结合在矿物中，存在于岩石的孔隙空间中，甚至在地球表面下许多公里处。在板块俯冲和大陆碰撞等构造事件期间，水从变质反应中的矿物中释放出来，与孔隙水一起可以作为热传输的媒介，并可以促进正在变形的岩石的弱化。在这个项目中，首席研究员和学生将研究加州东部怀特-因约山脉中生代发生的流体流动。在这一时期，怀特-伊尼奥山脉被深埋在北美地壳西缘的深处，随着大洋法拉隆构造板块俯冲到大陆之下，北美地壳正在经历变质作用、岩浆作用和火山作用。该地区的地质证据表明，深部地壳流体通过促进寄主岩石的变形，促进了花岗质深成岩体的侵位，并对该地区地壳的热液蚀变负责。PI和学生们将通过分析收集到的岩石中保存下来的变质矿物之间的热力学平衡关系，通过分析流体引起的碳酸盐矿物中碳和氧的比例变化，以及通过计算机模拟来研究中生代热液系统。据预测，影响流体流动几何形状和潜在平流热传输的关键因素是White-Inyo范围内岩石的可变渗透率。该项目的预期结果将是更好地了解深部地壳流体对大陆边缘地质发展的影响。怀特-伊尼奥山是大陆岩浆弧出土的一个极好的例子。该弧的岩浆活动发生在180-165 Ma和102-83 Ma两个时期，在时间上与内华达山脉的岩浆活动重叠。以前的构造和变质研究已经证实，这些深成岩体侵入了一个区域背斜，该背斜含有绿片岩相的页岩、石灰岩、钙质泥岩和砂岩。深成岩体的侵入产生了非均质水动力系统，非均质流体流动源于岩石的不同渗透率和面理。在该项目中，将利用碳酸盐矿物中的矿物平衡、变质反应和碳、氧同位素比值来确定哪些岩石经历了同变质流体流动。该项目的这些岩石学和地球化学部分将成为计算机模拟岩浆弧内接触光环和区域尺度上的反应流体流动的基础。计算机模拟将把流体流动与热传输和变质反应结合起来，它们将包括熔体结晶潜热、变质反应热以及反应和钚产生的流体的规定。该项目将对理解岩浆弧内的传导和平流热传输以及流体在促进大陆地壳深层岩石变形和重结晶方面的作用产生影响。

Water, besides being obviously present on the Earth?s surface, is also an integral part of the deep continental crust. In the crust, water is bound-up structurally in minerals and occurs in pore spaces of rocks, even many kilometers below the Earth's surface. During tectonic events, such as plate subductions and continental collisions, water is released from minerals during metamorphic reactions, and together with pore water can serve as a medium for heat transport and can promote weakening of rocks that are undergoing deformation. In this project, the Principal Investigator and students will study fluid flow that has occurred during the Mesozoic era in the White-Inyo Range of eastern California. During this era, the White-Inyo Range was buried deep within the western margin of North American crust that was experiencing metamorphism, magmatism, and volcanism as the oceanic Farallon tectonic plate was subducting beneath the continent. Geologic evidence in the range suggests that deep-crustal fluids promoted the emplacement of granitic plutons, by enhancing deformation of their host rocks, and were responsible for hydrothermal alteration of the crust within the range. The PI and students will study the Mesozoic hydrothermal system by analyzing the thermodynamic equilibrium relationships among preserved metamorphic minerals in collected rocks, by analyzing fluid-induced shifts in the ratios of carbon and oxygen in carbonate minerals, and by computer simulations. It is expected that the key factor that influenced the geometry of fluid flow and potential advective heat transport was variable permeability of rocks within the White-Inyo range. The expected outcome of the project will be a better understanding of the influence that deep-crustal fluids have on the geologic development of continental margins.The White-Inyo Range is an excellent example of an exhumed continental magmatic arc. Magmatism in the arc occurred during two time periods, 180-165 Ma and 102-83 Ma ago, and it overlapped in time with magmatism in the Sierra Nevada Range. Previous structural and metamorphic studies have established that the plutons intruded a regional anticline that contains greenschist-facies shales, limestones, calcareous argillites, and sandstones. Intrusion of the plutons generated heterogeneous hydrodynamic systems, with heterogeneous fluid flow stemming from variable permeabilities and foliations of the rocks. In the project, mineral equilibria, metamorphic reactions, and C and O isotope ratios in carbonate minerals will be used to determine which rocks experienced syn-metamorphic fluid flow. These petrologic and geochemical portions of the project will be the foundation for computer simulations of reactive fluid flow, on both contact-aureole and regional scales, within the magmatic arc. The computer simulations will couple fluid flow with heat transport and metamorphic reactions, and they will include provisions for latent heat of crystallization of melts, heats of metamorphic reactions, and for fluids generated by the reactions and plutons. The project will have an impact on understanding conductive and advective heat transport within magmatic arcs and on the role that fluids have on promoting deformation and recrystallization of rocks in the deep continental crust.