Geothermal and Tectonic Evolution of the Eastern Cordillera and the Subandean Ranges of Southern Bolivia

Abstract

Combined tectonic and geothermal investigations along a profile from Villamontes to San Vicente provide new ideas about the evolution of the Eastern Cordillera and Subandean Ranges of southern Bolivia. Sediment maturity was determined using reflectance and infrared spectroscopy measurements on organic matter as well as the crystallinity of illites and ranges from diagenetic in the Subandean Ranges to weak metamorphic in the Eastern Cordillera. The tectonic evolution is characterized by Hercynian movements producing a “Protocordillera” and the Andean orogeny with substantial crustal shortening which is compensated at a shallower level mainly in the Subandean Ranges while the Eastern Cordillera remains relatively stable.