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

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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.