Combine Use of Airborne Geophysical Methods to Constrain Geology

Abstract

Environmental aspects constitute main issues for our modern society in many ways, by the exploitation of natural resources or the development of road infrastructure. Studies of subsurface, called also Regolith, are at the crossroad of new geological point of view. Among wide range of geophysical methods, airborne geophysical tools is a fast method for providing informations about the near surface. Two different methods are been used: spectral radiometry and the time domain electromagnetic (TDEM). Spectral radiometry data were collected throughout “Region Centre” with a line space of 1km. The EM data were collected throughout three local boxes with a line spacing of 0.4 km. The three sites present very different geological and topographical characteristics. We have compared geological map with the two different airborne geophysical data. The three maps are consistent and show the same general structures but smallest structures are different. It appears that a decrease of resistivity a given geological formation is correlated with an increase of rock alteration. Moreover lowest potassium content seems to indicate the areas of accumulation of colluvial deposit. The 3D structure can be study with the TDEM data in regards of the resistivity variations.