Slides to Chapter G
Felsic intrusions II: porphyrocrystalline textures. The Porphyry System
Exemple : Gisements de type porphyre cuprifère
Aspect of the mining operation at Chuquicamata, Chile.
Photo Lluís Fontboté, 1991.10-4/16a Copyright © 1999 - Lluís Fontboté - All Rights Reserved
Open pit at Chuquicamata, Chile. View looking to the North.
Photo Lluís Fontboté, 1991.10-4/23a Copyright © 1999 - Lluís Fontboté - All Rights Reserved.
Open pit at Chuquicamata, Chile. View looking to the East. Observe the scale! (each bank about 20 m!)
Photo Lluís Fontboté, 1991.10-4/31a Copyright © 1999 - Lluís Fontboté - All Rights Reserved.
Open Pit at El Salvador, Chile. View looking to the West.
Photo Lluís Fontboté, 1994.10-5/33 Copyright © 1999 - Lluís Fontboté - All Rights Reserved.
The world-class mining district of Morococha covers an area of about 70 km2 in the Western Cordillera of central Peru and is part of the Miocene polymetallic belt. The central part of the district is dominated by the giant Toromocho porphyry Cu-Mo deposit. Multiple late-Miocene porphyry stocks intruded Permian, Triassic-Jurassic and Late-Cretaceous sedimentary carbonate and volcano-sedimentary formations, as well as large mid-Miocene barren intrusions. Epithermal polymetallic replacement bodies and veins overprint porphyry mineralization and skarns related to the subvolcanic Miocene intrusions. An ongoing Geneva research project in cooperation with several mining companies aims to unravel the ore formation history of the district. A key point of the project is to understand how in relatively short period of time (< 2 My) ore formation changed from porphyry ( 500°C, several km depth) to epithermal conditions (<300 °C, near surface environment).
Click on the picture for an enlarged version of this photograph (572 Kb)
More on Morococha district:
Catchpole H., Kouzmanov K., Fontboté L., Guillong M., Heinrich C. A. (2011) Fluid evolution in zoned Cordilleran polymetallic veins - Insights from microthermometry and LA-ICP-MS of fluid inclusions, Chemical Geology Volume 281, Issues 3–4, 24 February 2011, Pages 293–304
Catchpole, H., Kouzmanov, K., Fontboté, L. (2012) Copper-excess stannoidite and tennantite-tetrahedrite as proxies for hydrothermal fluid evolution in a zoned Cordilleran base metal district, Morococha, central Peru (archive-ouverte.unige.ch), Canadian Mineralogist, 2012, vol. 50, no. 3, p. 719-743