Sill emplacement and contact metamorphism in sedimentary basins

Abstract

Throughout the history, episodes of excessive volcanism, known as Large Igneous Provinces (LIP), have been emplaced into sedimentary basins. The heat transfer from these volcanic intrusions have important implications for the maturation of organic material and hydrocarbon generation in the heated sediments. One of the most important results of this thesis is the quantification of this gas generation, showing that several thousand gigatonnes of the potent greenhouse gas methane could be generated during these volcanic episodes. The thesis show that the methane could have been rapidly released to the atmosphere through thousands of several kilometer deep cylindrical pipe structures formed due to the pressure buildup arising from the gas release in the tight shales. The study is based on the development of a numerical model and calibration with data from the Karoo Basin, South Africa. The inferred gas generation and release are of such magnitude that it can explain global warming and carbon cycle perturbations at the times of LIP-emplacement.