The effect of igneous intrusive bodies on sedimentary thermal maturity

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 about a million years for all but the most exceptional geological conditions. Two case studies are provided which 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 time of intrusion. Corollorative implications for localized hydrocarbons generation, migration and accumulation are also discussed briefly.