Contribution to a New Genetical Concept on the Bolivian Tin Province

Abstract

SummaryThe Bolivian tin province is composed of four different groups of tin deposits distinguished by geotectonic setting, paragenesis, and geometric shape. There are Precambrian tin-bearing granites of the Brazilian Shield, Silurian meta-sedimentary strata-bound “manto” deposits, and two cycles of magmatic regeneration in Early Mesozoic (vein deposits) and Cenozoic time (tin porphyries). Heredity of tin derived from the Precambrian metallotect can be traced by exogene processes (paleo-placers) in Silurian, deep-seated magmatism in Mesozoic, and subvolcanic intrusions in Tertiary. The new evidence of Silurian synsedimentary cassiterite enrichment provides the missing link for a conclusive model of the metallogenetic development in the Bolivian crustal segment, thus proving the formation of different types of time- and strata-bound tin deposits in accordance with the geotectonic development of the continent.