It is very fortunate for our knowledge of the geological structure of Bolivia that three eminent geologists spent considerable time there. Alcides d’Orbigny travelled in Bolivia more than a century ago. He described the first fossils of the Silurian, Devonian, and Carboniferous and explored large parts of Eastern Bolivia (the Oriente), which were never again visited by a geologist. The first geological map of Bolivia is his work. Gustav Steinmann twice travelled in Andean Bolivia. His work and that of his coworkers was fundamental to our knowledge of the stratigraphy of the Paleozoic. Furthermore he also studied the “Puca formation” and dedicated himself to tectonic and petrographic problems. Roman Kozlowski, director of the School of Mines in Oruro from 1913 to 1922, advanced our knowledge above all in the paleontology of the Silurian, Devonian, and Carboniferous by his excellent monographs.
In spite of these researches and many subsequent investigations by other geologists, our knowledge of the geology of Bolivia is still spotty.
Bolivia shows a simple morphological and geological structure (Fig. 1). From east to west one can distinguish the following main elements of landforms:
(1) Old crystalline rocks of the Brazilian shield, for the most part covered by the alluvium of the lowlands of the Beni and the northern Chaco;
(2) Subandean zone, adjacent to the Andean system on the east;
(3) Eastern and Central Cordilleras, forming a uniform Paleozoic block;
(4) Altiplano depression which is covered along its western border by (5) Quaternary volcanic Cordillera Occidental.