Porphyry deposits are characterized by large-tonnage and low-grades related to porphyritic intrusions. Metals are primarily hosted in stockwork and breccia zones with some deposits exhibiting supergene enrichment. Porphyries exhibit large volumes of hydrothermal alteration up to tens of kilometers from the intrusive core. Spatially, they're related to subduction zone magmatism with the majority concentrated around the Pacific "ring of fire". Temporally, the most economically significant deposits are Late Mesozoic to Cenozoic in age (less than 200 million years old).
The video on Porphyry, IOCG, and Skarn has been provided by Andrew Jackson of Sprott Global Resource Investment Ltd.
Porphyry References (free):
- Porphyry Deposits
(2007) Sinclair, W.D., in Goodfellow, W.D., ed., Mineral Deposits of Canada: A Synthesis of Major Deposits-Types, District Metallogeny, the Evolution of Geological Provinces, and Exploration Methods: Geological Association of Canada, Mineral Deposits Division, Special Publication No. 5, 223-243 p.
- Anatomy of porphyry-related Au-Cu-Ag-Mo mineralsed systems: Some exploration implications
(2009) Corbett, G., Australian Institute of Geoscientists – North Queensland Exploration Conference, June 2009.
- Arc-Related Porphyry Molybdenum Deposit Model
(2010) Taylor, R.D., Hammarstrom, J.M., Piatak, N.M., and Seal, R.R. II, Chapter D of Mineral deposit models for resource assessment: U.S. Geological Survey Scientific Investigations Report 2010−5070–D, 64 p.
- Porphyry Copper Deposit Model, Chapter B of Mineral Deposit Models for Resource Assessment
(posted September 2, 2010) John, D.A., Ayuso, R.A., Barton, M.D., Blakely, R.J., Bodnar, R.J., Dilles, J.H., Gray, Floyd, Graybeal, F.T., Mars, J.C., McPhee, D.K., Seal, R.R., Taylor, R.D., and Vikre, P.G., Chapter B of Mineral deposit models for resource assessment: U.S. Geological Survey Scientific Investigations Report 2010—5070–B, 169 p.
- Climax-Type Porphyry Molybdenum Deposits
(2009) Ludington, Steve, and Plumlee, G.S., 2009, U.S. Geological Survey Open-File Report 2009–1215, 16 p.
- Preliminary Model of Porphyry Copper Deposits
(2008) Berger, B.R., Ayuso, R.A., Wynn, J.C., and Seal, R.R., U.S. Geological Survey Open-File Report 2008–1321, 55 p.
- A Tectonic Model for the Spatial Occurrence of Porphyry Copper and Polymetallic Vein Deposits—Applications to Central Europe
(2005) Drew, L.J., U.S. Geological Survey Scientific Investigations Report 2005-5272, 43 p.
- Porphyry Deposits of the Canadian Cordillera
(1991) McMillan, W.J. in Ore Deposits, Tectonics and Metallogeny in the Canadian Cordillera, Paper 1991 - 4,
Porphyry Copper and Other Intrusion-Related Mineralization in Mexico
(1995) Barton, M.D., I.G. Staud, E.L. Zurcher, and P.K.M Megaw in F.W. Peirce and J.G. Bolm, editors, Porphyry Copper Deposits from Alaska to Chile, Arizona Geological Society Digest v. 20, 487-524. Paper courtesy of Mark Barton and the University of Arizona, Tuscson.