Metallogenesis of the world's largest silver deposit - Cerro Rico, Bolivia

摘要

Bolivian polymetallic vein (BPV) deposits are large, intrusive-related, sulphide-dominated polymetallic vein systems. Typically they span the mesothermal to epithermal environment. They are significant producers of silver, tin, zinc and gold. Cerro Rico is a classic example, and is the world's largest silver deposit. Since its discovery in 1544, it has produced at least 1 billion ounces of silver. In this paper, we address a central question -what made Cerro Rico so big? Hypogene mineralisation is hosted by a sheeted, polymetallic vein system. This cross-cuts a pervasively altered rhyodacite dome which intrudes Palaeozoic marine sediments and an overlying Miocene sequence of caldera-related volcanics. The dome, which has been dated by ~(40)Ar/~(39)Ar methods at 13.8 Ma, is the high-level expression of a deeper intrusive body which supplied heat, volatiles and metals to an evolving hydrothermal system. Intrusion of the deep pluton may have been guided by the intersection of a NF-trending regional fault and the N-S-trending Carma lineament.