The Modification of Sedimentary Thermal Maturity by Igneous Sills

Abstract The high temperatures of igneous intrusives cause localized thermal maturity of sediments far in excess of the regional variation. Previous studies have shown that igneous bodies cool in less than a million years for all but the most exceptional geological conditions. Two case studies show how the increase in thermal maturity around an igneous body can be used to assess the temperature of the intrusive at emplacement and also the insertion time.