Aplicación de técnicas estructurales y geoquímicas para la caracterización de fracturas conductoras en el batolito de La Cabrera (España central)

Abstract

Groundwater flow and solute transport within fractured crystalline rocks are mainly controlled by the geometry and the properties of each individual fracture. The hydrogeological characterization of a g ra n itic m assif is usually achieved b y a large n u m b e r o f destructive boreholes. This is undesirable in the case that the area is studied as a possible nuclear waste repository. Discrete fracture network models are good interpreters of the local hydraulic properties measured in situ. The extension of these types of models to a regional scale is limited by the high number of fractures that must be characterized and simulated. The applicability of two techniques ("Fault Population Analysis", geological techniques, and "Emanometry", geochemical technique) is analyzed and discussed to define the conductive fractures In the granitic massif. The objectives are: 1) to reduce the number of destructive boreholes and to place them; 2) to decrease the computer time and increase the scale of application of the discrete fracture network models. In this study the filtering made from the results of the two applied techniques has reduced the number of representative disks of the conductive fractures in 23 percent