Hollows are common features of the landscape in the studied area. In some of them the presence of gullies was detected. To know the subsurface structure of the slope were they occur may enable a better understanding of gully development. The sampled hollow occurs on the granite complex of the crystalline basement of Gouveia in an area marked by tectonic contact which schist, showing also the presence of granite and schist millonites. In the lower part of the hollow gully process had been taking place regardless of a dense vegetation cover of grass and shrubs. The hollow was surveyed with GPR (Ramac) with 50 MHz and 100 MHz antennas. The GPR emits EM-pulse wave down to the ground by the transmitter antenna. The wave reaches the target, refracting and reflecting back to the surface where the receiver antenna receives it. The refraction and reflection are constraints by the contrast of dielectric properties between the soils/rocks discontinuities (dielectric impedance). The time-section conversion to depth-section is done using the velocity obtained by the CMP (common mid point) survey. The GPR profiles were carried out in both directions, perpendicular and parallel to the main direction of gully drainage, which is almost N-S. The perpendicular profile was obtained on the left border of the hollow; the others were perpendicular to the gully drainage direction using both antennas: one next to the gully head and the other at the hollow mound. The CMP's profile was obtained at each initial profile point. The data was processed using standard procedures: decliping, filtering, gains, and migration. Geomorphological, geological and pedological profiles information from the area was added to allow the interpretation of these sections. Some structural features were identified: fractured zone and its (apparent) direction, quartz veins, geologic contact, water table, soil/rock contact.
*This study was financially supported by FAPEMIG.