3D Gravimetric Characterization of El Bierzo Carboniferous Basin and Ponferrada Granite, León, NW

The aim of this work is to present the results of a 3D geological model based on probabilistic inversion of structural gravity data. The gravity data was acquired using high resolution GPS positioning for X, Y and Z coordinates. Prior to the modelling, a Bouguer anomaly map has been obtained and interpreted in terms of regional-residual separation, vertical gradient, geophysical lineaments and Euler solutions. The study area comprises El Bierzo Carboniferous Basin and the Ponferrada granite. The deep structure of the basin and the granite morphology has been obtained from the inversion, using information from reflection seismic profiles together with data from wells and density values from rock samples to constrain the geometry and physical properties of the model. The results favour the hypothesis that the western limit of El Bierzo Basin is a vertical fault, NNE-SSW trend, showing small displacement that does not outcrop because is covered by Tertiary sediments and also indicate that the Ponferrada granite extends below the Tertiary cover towards the NW. Next to that granite another subcropping intrusive body has been modelled, deduced from its gravimetric signature. This body can be part of the post hercinic aloctonous leucogranites.