Quantitative Evaluation of the Roles of Fluid Infiltration During Contact Metamorphism in the Alta Stock Thermal Aureole, Little Cottonwood Canyon, Utah

碳酸盐岩变质过程中流体的渗透程度及其在变质过程中对反应过程、孔隙流体组成和热收支的影响，是变质地质学家面临的基本但尚未解决的问题。虽然最近的几项研究已经确立了流体渗透的重要性，但这一过程的细节（例如，渗透的数量和方式、时间、对孔隙流体组成的影响、与结构的关系等）并没有得到很好的约束，而且存在争议。此外，流体渗透在接触变质光晕对流换热中的具体作用尚未得到详细的研究。对犹他州Little Cottonwood Canyon地区Alta Stock热光圈的接触变质硅质白云岩进行了全面的岩石学、相平衡、同位素和传热研究。这些白云岩在接触变质作用中被贫180富水流体渗透。研究的目的是利用岩石学和稳定同位素技术定量评价流体对白云岩大理岩的渗透程度，确定渗透流体的来源，并确定渗透的几何形状和类型（例如，普遍渗透或沿构造或层理优先通道化）。这些结果将限制流体渗透的热后果的数值模拟，以光圈中的传热和Alta Stock的总热损失。

The extent of fluid infiltration accompanying the metamorphism of carbonate rocks, and its roles in influencing reaction progress, pore fluid compositions, and thermal budgets during metamorphism, are fundamental but unresolved questions to metamorphic geologists. Although the importance of fluid infil- tration has been established with several recent studies, the details of the process (e.g., amounts and infiltration style, timing, influence on pore fluid composition, relationships to structures, etc.) are not well constrained and are controversial. In addition, there have been no detailed studies of the specific roles of fluid infiltration in convective heat transfer in contact metamorphic aureoles. A comprehensive petrologic, phase equilibria, isotope, and heat transfer study is proposed for the contact metamorphosed siliceous dolomites of the equilibria, isotope, and heat transfer study is proposed for the contact metamorphosed siliceous dolomites of the Alta Stock thermal aureole in Little Cottonwood Canyon, Utah. These dolomites have been infiltrated during contact metamorphism by 180-depleted and water-rich fluids. The objectives of the study are to use petrological and stable isotope techniques to quantitatively evaluate the extent of fluid infiltration into the dolomitic marbles, to determine the sources of the infiltrating fluids, and to define the g eometry and styel (e.g., pervasssive or channelized preferentially along structurs or bedding) of infiltration. These results will constrain numerical modelling of the thermal consequences of fluid infil- tration to heat transfer in the aureole and to total heat loss from the Alta Stock.