3D geological model of the northern Po plain near Brescia.

A 3-D reconstruction of the texture distribution of the subsoil in the Brescia plan region is presented. The area is located between the morainic amphitheatres of Iseo westward and of Garda eastward. It is characterised by fluvial and fluvioglacial deposits in which the texture sizes decrease southward. The thickness of the sedimentary bodies southward. According to geomorphological and pedological considerations, the age of the deposits below the surface is Last Glacial Maximum (LGM). Using a water well data base TANGRAM, developed in the IDPA-CNR Milano, 415 well data are stored, georeferenced and their stratigraphic logs are translated into alphanumeric codes. Textural well data can be translated and imported into GOCAD (Geological Object Computer Aided Design), where a set of 3-D special virtual objects is easily constructed. Two surfaces, topography (DTM) and aquifer bottom in the subsoil, are imported into GOCAD from a GIS. Between these two surfaces a 3-D grid (SGrid) is reconstructed with 3-D cells (Voxel). The wells are located on a DTM and are defined by marker levels which correspond to different stratigraphic layers. The percent of texture size Gravel, Sand and Silt-Clay is assigned to each stratigraphic layers of the wells. Using the three dimensional grid, these values are assigned to the nodes of the 3-D grid and then processed. In this way, the distribution of texture is calculated for each voxel on the whole 3-D volume of the subsoil.