Heat flow pattern at the Chicxulub impact crater, northern Yucatan, Mexico

Abstract

Along an east–west profile crossing the Chicxulub impact structure in northern Yucatán, México, Curie depths were obtained from statistical-spectral analysis of a grid of aeromagnetic data (256km wide and 600km long). These depths were corrected for flight height and depth to the sea floor to determine the geothermal gradient, assuming a temperature of 580°C for the Curie temperature. Heat flow was then calculated from the geothermal gradients using a value of 2.67W/m-K for the mean crustal thermal conductivity. The results show a conspicuous heat flow high above on the impact basin. In this location, the heat flow is 80mW/m2 approximately. Available offshore estimates of the depth to the crustal magnetic source bases, on the northern Yucatán platform, and onshore heat flow determination on 8 shallow bore holes, and in a 1511m deep one, support the existence of this major high heat flow anomaly associated with the impact crater. This high heat flow might be related to the impact through: (1) an uplift of the crystalline basement rocks in the center of the crater; and (2) impact induced radioactive element concentration into the crust below the impact structure. Higher thermal conductivities at the lower crust might also play a key role. Available seismological and thermal property data are compatible with these mechanisms.