Abstract: Thermal Conductivity and Radiogenic Heat Production of Sedimentary Rocks from the Gulf of Mexico Basin (South Texas)

Thomas E. McKenna, J. M. Sharp Jr., F. L. Lynch

Thermal conductivity and alpha-particle emission (for calculation of radiogenic heat production) were measured on over 100 sedimentary rock samples from the South Texas portion of the Gulf of Mexico Basin. These are the first reported radiogenic heat calculations for the Gulf of Mexico Basin and the first thermal conductivity measurements for the Texas area. Detailed petrology and/or whole-rock analyses were available for most of the samples. Thermal conductivity is inversely proportional to porosity and directly proportional to quartz content. Wilcox sandstones have a higher thermal conductivity than Frio sandstones with similar porosities because of the increased quartz content of Wilcox sandstones. Ranges of thermal conductivities are: for Wilcox sandstones, 3 to 6 W/m/K for porosi ies of 3% to 20%; for Frio sandstones, 2 to 3 W/m/K for porosities of 13% to 30%; and for Stuart City limestones, 3 to 3.5 W/m/K for porosities from 0% to 7%. Ranges of radiogenic heat production are: for Frio shales, 1.2 to 2.3µ W/m³; for Wilcox shales, 0.8 to 2.0µ W/m³; for Frio sandstones, 0.6 to 1.6µ W/m³; and for Stuart City Iimestones, 0.1 to 1µ W/m<sup3/. Steady-state, one-dimensional heat conduction models suggest that radiogenic heat production can contribute significantly, to overall heat-flow density, especially in shale rich parts of the basin where thermal conductivity is relatively low.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994