2020 SEG Thayer Lindsley Visiting Lecturer to Massimo Chiaradia and publication in Nature Communication
Massimo Chiaradia (University of Geneva) has been selected as the 2020 SEG Thayer Lindsley Visiting Lecturer on the basis of widely recognized expertise in a field of economic geology. Moreover, he published a new paper in Nature Communication
Massimo Chiaradia (University of Geneva) has been selected as the 2020 SEG Thayer Lindsley Visiting Lecturer on the basis of widely recognized expertise in a field of economic geology.
He also published in Nature Communication, see the abstract bellow:
Precipitation efficiency controls gold endowments in porphyry deposits
Porphyry copper-gold deposits are natural suppliers of most copper and significant gold to our society. They are large volume, low-grade disseminations formed by precipitation of copper and gold from fluids of magmatic origin. Whereas the Cu-richest (Au-poor) porphyries are related to Andean-type subduction and typical calc-alkaline magmatism, the Au-richest porphyries are associated with high-K calc-alkaline to alkaline magmatism in late to post-subduction or post-collision and extensional settings, and subordinately with calc-alkaline magmatism. The reasons of these associations and of the large variations in metal endowments of porphyry Cu-Au deposits remain obscure. Here, I show that porphyry Cu-Au deposits define two distinct trends in Au versus Cu tonnage plots (Cu-rich and Au-rich). Metal endowments for both trends grow larger the longer the mineralization process is. However, Au is precipitated at much higher rates in Au-rich than in Cu-rich porphyry deposits. Using Monte Carlo simulations of petrologic processes, I show that whereas Cu-rich porphyries require large amounts of magma and water to be formed, Au-rich porphyries are the result of a better efficiency of Au precipitation.
par Fabienne Dietrich