Estudios de exploración geoeléctrica sobre la Formación Marifil entre Puerto Madryn y Telsen (provincia de Chubut)

Abstract

Geomorphological studies between Puerto Madryn (42 o 30 S y 65o 00´ W) and Telsen (42 o 40´ S y 67o 00´ W) are carried out in an attempt to know the evolution of the landscape from the Jurassic period. Volcanic rocks of the Marifil Formation are the main outcrops in the area, constitute the basement in the area and their exposures form hills which tend to align in a north-south direction. In this study, where the Marifil Formation is covered with sedimentary deposits, a geoelectrical prospection was made. In order to determine the thickness of the sedimentary cover, the variation in the morphology and the depth of the basement, sixteen Vertical Electrical Soundings (VES) were done. A Schlumberger tetraelectrodic configuration was used for each VES and the sounding curves were interpreted automatically through an iterative process. Geoelectrical layer models were obtained and the error considered was always less than 2.5%. For the geological interpretation of each geoelectrical model, both the geological information of the area and the data from an exploration hole were considered, whose electrical logging and litology were used for the parametric reference of the soundings. These models allowed to define the variations in the thickness of the sedimentary fill, which reaches in some sites up to 174 m. A geoelectrical cross section located south of Telsen showed a progressive deeping of the basement toward the South.