Numerical modelling of burial and temperature history as an approach for an alternative interpretation of the Bramsche anomaly, Lower Saxony Basin

Abstract

The Lower Saxony Basin, Germany, is one of the several sedimentary basins within the Central European Basin system. In its southwestern part, anomalously high maturity of organic matter has been observed to reach 4.5% VRr in Upper Jurassic and Lower Cretaceous sedimentary rocks in an area which coincides with a magnetic and a positive gravimetric anomaly. This anomaly was often interpreted as the consequence of a deep-seated igneous intrusion, the so-called Bramsche Massif. However, results obtained from calibrated numerical modelling are not in accordance with this scenario. Instead, a burial by approximately 4 km of now-eroded Cretaceous rocks was revealed to be the probable cause for the anomaly. Data and modelling results from six boreholes and two pseudo-wells support this view.