Influence of sill intrusions on the hydrology and thermal maturity of sediments - Modelling heat flow and organic geochemical alterations

To demonstrate the effectiveness of the above concept, we employ a derivate of BGR’s heat flow model which has been used and proven as a robust analytic tool in a variety of published studies. Our calculations demonstrate the massive temperature depression caused by the steam production in comparison to the case of pure heat transfer by conduction. After sill emplacement steam generation will ensue until the latent heat for steam formation for the given water volume has been supplied by heat flow out of the sill. During this process, the contact temperature will be kept at the steam point of water for the given pressure at the sill depth. As soon as the latent heat is used up, the heat flow from the sill will drop below the capacity to heat the water to the steam point. The contact temperature will thereafter slowly drop, sediments and sill will proceed to cool jointly. To test our model with observations, we included routines of kinetic modelling of thermal vitrinite alteration, and compared the computational results to data from different settings worldwide. The comparison between modelled and observational data are in very good accordance.