9805102 Nabelek The PI will conduct a numerical study of contact metamorphism in the calc-silicate Notch Peak aureole, Utah, to obtain better understanding of hydrodynamic parameters that control thermal evolution and fluid flow in contact aureoles. They will build on currently available petrologic and geochemical parameters on flow of reactive fluids as reflected by mineral assemblages and geochemistry of the aureole. The parameters include: (1) budget of magmatic, metamorphic and formation fluid sources, (2) layered, lithologically controlled permeability structure of the aureole, (3) transient porosities, including those resulting from fracturing and volume changes in metamorphic rocks, (4) transient thermal field, (5) latent heat of crystallization of magma, (6) consumption of heat by metamorphic reactions and heating of fluids, and (7) observed geometry of the intrusion and its aureole. Numerical simulations will be constrained by previous petrologic and geochemical results on fluid flow in the overall aureole and by detailed morphologic, mineralogic, and stable isotope analyses of outcrops. The outcrop-scale data will give indications of flow geometry, type of porosity and permeability, and fluid flux on scale of individual beds. Besides a better understanding of the Notch Peak aureole, the results will be a significant contribution to the knowledge of metamorphism, because the parameters to be investigated are fundamental to fluid flow associated with all contact aureoles.
