One-dimensional models predict the spatial distribution of mineral assemblages developed in siliceous dolomitic limestones during three conditions of contact metamorphism and fluid-rock interaction: (1) rock containing a fixed porosity filled with stagnant CO2-H2O fluid, (2) horizontal fluid flow in the direction of increasing temperature, and (3) horizontal flow in the direction of decreasing temperature. For a given pressure, temperature profile, and rock composition, and assuming local mineral-fluid equilibrium, stable assemblages may be mapped on diagrams of distance from the contact vs. fluid amount (porosity, phi, or time-integrated flux, q, as appropriate). The topology of the diagrams differs for the three cases of fluid-rock interaction. Observed mineral assemblages in specific aureoles therefore may be interpreted in terms of the amount and direction of fluid flow (if any). Review of seven case studies of contact-metamorphosed siliceous dolomitic limestones indicates that unless phi > 14%, fluid flow occurred in each instance. No universal statements, however, may be made about the geometry of flow. The outer portions of five aureoles (Alta, Utah; Beinn an Dubhaich, Scotland; Boulder, Montana; Kasuga-mura, Japan; and Marysville, Montana) contain a mineralogical record consistent with horizontal fluid flow in the direction of increasing temperature with q almost-equal-to 10-800 mol/cm2. Two localities (Alta and Beinn an Dubhaich) show evidence for flow in the direction of decreasing temperature in the innermost portion of the aureole with q < 1300 mol/cm2. In one aureole (Elkhorn, Montana), fluid probably flowed horizontally down-temperature in the outer portion (q almost-equal-to 35-165 mol/cm2) and upward near the contact. Results emphasize that mineral assemblages in metacarbonate rocks are controlled not only by temperature,, pressure, rock composition, and fluid composition but also by the amount and direction of fluid flow.
