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.
List of papers
(chapter 6 is removed due to publisher restrictions)
How contact metamorphism can trigger global climate changes: Modeling gas generation around igneous sills in sedimentary basins by Ingrid Aarnes, Henrik Svensen, James A. D. Connolly and Yuri Y. Podladchikov. Manuscript accepted in Geochimica et Cosmochimica Acta. Published version: GEOCHIMICA ET COSMOCHIMICA ACTA 2010, 74(24), 7179-7195. DOI: 10.1016/j.gca.2010.09.011
Contact metamorphic devolatilization of shales in the Karoo Basin, South Africa, and the effects of multiple sill intrusions by Ingrid Aarnes, Henrik Svensen, Stephane Polteau and Sverre Planke. Manuscript submitted to Chemical Geology. Published version: CHEMICAL GEOLOGY 2011, 281(3-4), 181-194. DOI: 10.1016/j.chemgeo.2010.12.007
Fluid overpressure and rate of devolatilization during metamorphism by Ingrid Aarnes, Yuri Y. Podladchikov and Henrik Svensen. Published version: Geofluids 2012, 12(4), 265–279. DOI: 10.1111/j.1468-8123.2012.00368.x
Sandstone dikes in dolerite sills: Evidence for high pressure gradients and sediment mobilization during solidification of magmatic sheet intrusions in sedimentary basins by Henrik Svensen, Ingrid Aarnes, Yuri Y. Podladchikov, Espen Jettestuen, Camilla H. Harstad and Sverre Planke. Published version: GEOSPHERE 2010, 6(3), 211-224. DOI: 10.1130/GES00506.1
Post-emplacement melt flow induced by thermal stresses: Implications for differentiation in sills. Aarnes, I., Podladchikov, Y. Y. and Neumann, E.-R. (2008) Post-emplacement melt flow induced by thermal stresses: Implications for differentiation in sills. Earth and Planetary Science Letters, 276, 152-166. DOI: 10.1016/j.epsl.2008.09.016