eCite Digital Repository

Geochemistry of Porphyry Deposits

Citation

Cooke, DR and Hollings, P and Wilkinson, JJ and Tosdal, RM, Geochemistry of Porphyry Deposits, Treatise on Geochemistry, Elsevier, H Holland, K Turekian (ed), Italy, pp. 357-381. ISBN 978-0-08-098300-4 (2014) [Research Book Chapter]

Copyright Statement

Copyright 2014 Elsevier Ltd.

DOI: doi:10.1016/B978-0-08-095975-7.01116-5

Abstract

Porphyry ore deposits typically form in convergent plate margin or postsubduction settings at depths of 1-6. km. Oxidized hydrous melts derived from the metasomatized mantle wedge transport Cu, Au, Mo, and other metals to upper-crustal magma chambers. Ponding and release of these magmas is promoted by transient compressional events that perturb steady-state subduction processes, such as the subduction of aseismic ridges or oceanic plateaus. Fractional crystallization leads to repeated cycles of volatile exsolution, vein stockwork formation, and hydrothermal brecciation within and above the mineralizing intrusions. Radiometric dating provides evidence for multiple mineralizing episodes over several million years in some deposits and durations of less than a few hundred thousand years for magmatism and mineralization in others.Metals are transported by high-temperature brines, vapors, or vapor-like supercritical fluids, depending on local confining pressures. Ore deposition may occur due to decreasing temperature, decreasing pressure, sulfate reduction, water-rock interaction, SO2(g) disproportionation, condensation, or combinations thereof. Stable isotopic data indicate a predominance of magmatically derived sulfur, oxygen, deuterium, copper, iron, and molybdenum in the mineralized core of many porphyry deposits. Lead isotopes provide insights into crustal assimilation processes where there are significant differences in the isotopic compositions of local crustal and mantle sources of Pb. © 2014 Elsevier Ltd. All rights reserved.

Item Details

Item Type:Research Book Chapter
Keywords:porphyry, copper, gold, molybdenum, geochemistry
Research Division:Earth Sciences
Research Group:Geology
Research Field:Ore Deposit Petrology
Objective Division:Mineral Resources (excl. Energy Resources)
Objective Group:Mineral Exploration
Objective Field:Copper Ore Exploration
Author:Cooke, DR (Professor David Cooke)
Author:Wilkinson, JJ (Professor Jamie Wilkinson)
ID Code:98517
Year Published:2014
Funding Support:Australian Research Council (CE0561595)
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2015-02-18
Last Modified:2017-11-02
Downloads:2 View Download Statistics

Repository Staff Only: item control page