This study interprets the regional geology and structure of the Altiplano, Andean foothills, and adjacent basins of Bolivia. It is based on 15 gravity surveys and 13 magnetic surveys covering more than 1,000,000 sq. km and representing most of the potential field data collected in Bolivia prior to mid- 1997. The interpretation is also based on over 2000 km of seismic profiles, 93 wells, and regional geology.

The gravity field reflects Andean structures, the thickness of the sedimentary section, and the thickness of the crust. There is a high coefficient of correlation between the residual gravity field and the depth to the top of the Devonian system. The magnetic field, however, correlates better with pre-andean structures, and pre-Cambrian to early Paleozoic-age faults and terrain boundaries. Magnetic anomalies follow andean structures only when the andean deformation is controlled by basement structures. Three sets of magnetic lineaments in the altiplano are related to inverse and transcurrent faults.

Important basement structures identified by gravity and magnetic anomalies include the Izozog and Boomerang arches, the Madidi high, and the Sirimenquis high. Magnetic anomalies measured over the subandean basins of northern Bolivia are high amplitude and high frequency, reflecting shallow depths to magnetic basement. Magnetic lineaments in northern Bolivia can be traced into Peru and Brazil. In the subandean fold belt of southern Bolivia, detachment horizons are found in the upper and lower Devonian, and lower Carboniferous rocks and ramp angles average twenty degrees.