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Anhydrite-bearing andesite and dacite as a source for sulfur in magmatic-hydrothermal mineral deposits


Chambefort, I and Dilles, JH and Kent, AJR, Anhydrite-bearing andesite and dacite as a source for sulfur in magmatic-hydrothermal mineral deposits, Geology, 36, (9) pp. 719-722. ISSN 0091-7613 (2008) [Refereed Article]

DOI: doi:10.1130/G24920A.1


Magmatic anhydrite from andesites and dacites occurs as inclusions in high- and low-aluminum amphibole and pyroxene and indicates that sulfate-saturated magmas spanned a period of six million years at Yanacocha, Peru. Magmatic anhydrite from Yanacocha and other sites is characterized by light rare earth element - enriched patterns and elevated strontium contents distinct from magmatic-hydrothermal anhydrite. Petrologic arguments suggest that the hydrous and oxidized Yanacocha magmas contained more than ∼1000 ppm sulfur both dissolved in the melt and as a separate sulfate phase, which is sufficient to provide all the sulfur for the genetically related giant sulfur-rich Yanacocha epithermal gold deposits. High-aluminum amphiboles contain unusual anhydrite with wormy and amoeboidal textures, which are tentatively interpreted to represent trapping of an immiscible CaSO4-water melt together with sulfur-rich apatite at a temperature of ∼950 °C and a water pressure >3 kbar: Such unusually sulfate-rich magmas may be required to produce sulfur-rich magmatic-hydrothermal mineral deposits. © 2008 The Geological Society of America.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geology
Research Field:Igneous and metamorphic petrology
Objective Division:Mineral Resources (Excl. Energy Resources)
Objective Group:Mineral exploration
Objective Field:Precious (noble) metal ore exploration
UTAS Author:Chambefort, I (Dr Isabelle Chambefort)
ID Code:52905
Year Published:2008
Web of Science® Times Cited:82
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2008-10-09
Last Modified:2008-10-09

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