How our phones are connected to volcanoes? Come and see how the largest copper treasures of the Earth form!
Massimo Chiaradia, Hugo Carrasco, Erwan Delfaud, Eliana Noroña
Affiliations: Department of Earth Sciences, University of Geneva, Geneva, Switzerland
Presentation type: Demonstration
Demonstration time: Check the SciCom program, Room Esplanade
Programme No: 7.4.13
Abstract
Volcanoes are intertwined with human life since prehistoric times. Whereas on one hand they may be source of destruction, on the other they provide elements that are essential to humans, like potassium and magnesium which are fertilizers of soils for agricultural crops. Perhaps less known, volcanoes are also, in some rare cases, intimately associated with the major sources of copper on Earth. Copper has been one of the most important metals for human civilization and, nowadays, is essential for the transition to a green economy. It is estimated that its demand will overcome known natural resources within a few years, which is fostering efforts to find new copper resources. The largest natural copper resources are the so-called porphyry copper deposits. Most of these deposits form 1-6 km under volcanoes associated with subduction zones, like those of the Andean Cordillera in South America. The magma reservoir under volcanoes may feed explosive eruptions through the catastrophic liberation of fluids inside the magma ascending towards the surface, but may also release fluids in a quieter way. Such fluids consist principally of water, some chlorine and sulfur and trace amounts of copper and other metals. Copper is precipitated as copper-rich sulfide minerals, like chalcopyrite (CuFeS2), due to cooling of the fluids released by the magma reservoir when they ascend towards the surface. Here we will present a model of how porphyry copper deposits form, also showing samples of rocks and minerals, and how they relate to the life of a volcanos.