Estimating amount and timing of Late Palaeozoic uplift and erosion in the Rønne Graben, Bornholm, Denmark

Abstract

Late Palaeozoic uplift and erosion is evidenced by a discontinuous vitrinite reflectance profile of the Pernille-1 well situated in the Rønne Graben. Modelling vitrinite reflectance evolution by the methods of basin modelling, the unconformity is estimated to represent Late Carboniferous uplift and erosion of 3,300 m of Upper Silurian and Devonian sediments. Given a vitrinite reflectance value of 1.7% at the erosional surface, the maximum temperature obtained during deepest burial is 160-165°C, corresponding to a geothermal gradient of approximately 50°C/km. The sensitivity of the erosion estimate to the choice of model parameter values is quantified. For example, a +10% uncertainty in the geothermal gradient equals an uncertainty of +400 m in the erosion estimate.