Geology of Bolivia

The country is divided into a mountainous western area affected by the subduction processes in the Pacific and an eastern lowlands of stable platforms and shields.

The eastern lowlands and sub-Andean zone in Santa Cruz, Chuquisaca, and Tarija Departments was once an old Paleozoic sedimentary basin that hosts valuable hydrocarbon reserves.

It has been hypothesized that the central Andes gained its great height 26 to 14 mya as result of a compressive failure of the lithosphere beneath Bolivia and neighboring areas.

[2] The great heights of the Altiplano, Codillera Occidental and Cordillera Oriental are isostatically compensated by an up to 70 km deep crust.

[3][4][5][6] A hypothesis holds that scarce sediment supply to the Atacama Trench caused by arid climate induced high shear stresses in the subduction process that enhanced the Andean mountain building.

The Altiplano plateau or Meseta del Collasuyu to differentiate it from other Andean high plateaux is a wide and long-lived intermontane sedimentary basin with no outlet; it is endorheic.

Today the Altiplano is believed to have been an early foreland basin of the "proto-Andes" that got uplifted by crustal shortening in the Late Miocene.

The emplacement of these igneous bodies have been interpreted as an effect of two temporary decreases in subduction angles of the ancient Farallon Plate.

[11] This arc of magmatic material hosts Bolivia's widely known tin belt as well as the famous silver mine of Potosí.

[12] The depositional environment for these channel systems has been likened to that on the floor of the present day Labrador Sea, which was influenced by repeated Pleistocene glaciations.

[13] The late Cenozoic deformation associated with the Andean orogeny forced hydrocarbons sourced in Devonian shales to migrate to shallower stratigraphical levels.

[16] The shield expresses itself topographically as a large elevated hinterland located north of Serranías Chiquitanas towards the Brazilian border.

[citation needed] The East-West Río Mercedes Line in the Guaporé Shield hosts several Proterozoic diabase intrusions.