Potassium, uranium, thorium radiogenic heat contribution to heat flow in the precambrian and younger silicic rocks of the Zuni and Florida mountains, New Mexico (U.S.A.)

High heat flow in the Zuni Mountains, New Mexico, U.S.A., has been explained by the possible presence of a buried felsic pluton. Alternately, high K, U, Th abundances have been proposed to account for part of the high heat flow. The mean radiogenic heat contribution for 60 samples of Precambrian core rocks is 7.23 μcal/gm-yr, which is slightly higher than the average for western U.S.A. granitic rocks and significantly higher than the average for continental “crust”; hence, the K, U, Th radiogenic contribution from Precambrian rocks to the overall heat flow is significant. Radiogenic K, U, Th heat for 32 samples for the Florida Mountains, New Mexico, U.S.A., yields a lower mean of 5.46 μcal/gm-yr. This value is somewhat anomalous in that the predominantly syenitic rocks commonly yield higher values. Furthermore, heat flow is higher in areas distant from the Floridas and the radiogenic heat contribution is considered small.