Overthickening of sedimentary sequences by igneous intrusions

The identification of extensive intrusive igneous complexes both in subsurface data and in field studies has resulted in quantification of the volumes of igneous material. Despite this research there is still little connection established between the amount of igneous material intruded into a basin and its effect on subsequent basin evolution in terms of burial and loading. To understand how additional igneous material may influence basin evolution we investigate igneous intrusions from the Faroe-Shetland Basin (FSB) utilising subsurface data. This study highlights that the total estimated thickness of sediment during Cretaceous is likely an overestimate as the sedimentary fill consists of significant quantities of igneous material which was emplaced during the Paleocene (56 Ma).
Previously this additional igneous material has not been accounted for in estimates of sedimentation rates and the burial history of the FSB. Importantly petroleum system modelling to understand generation and expulsion of hydrocarbons benefits from correct estimates of basin fill. The overthickening of basins by igneous material will affect the timing of hydrocarbon generation and subsequently the proper evaluation of exploration targets. In order to fully understand basin evolution the volumes of igneous material and when this material was emplaced must be acknowledged and considered.