Wiemer, Daniel, Hagemann, Steffen G., Kemp, Anthony I., Thebaud, Nicholas, Ireland, Trevor, and Villanes, Carlos (2021) Timescales and Processes of Au and Cu Fertile Magmatic-Hydrothermal Reservoir Accumulation in Continental Arcs. In: [Presented at the SEG 100 Conference]. 4154. From: SEG 100 Conference: Celebrating a Century of Discovery, 14-17 Spetember 2021, Whistler, Canada.

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Abstract

Continental arc systems are loci of world-class Cu-Au porphyry and intrusion-related orogenic Au vein deposits. The subduction environment facilitates high magma and fluid fluxes, acting as a heat engine and promoting metal transport. How and when, during the lifetime of an accretionary orogen, Cu and Au fertile magmas are generated and ore-producing fluids are expelled, remains elusive.

We present combined structural, geochemical, and zircon trace element, U/Pb and Lu/Hf isotopic data from the Carboniferous Eastern Andean Cordillera, northern Perú. Our geochemical data demonstrate that primitive, mantle-derived calc-alkaline diorite magmas are hydrous, oxidized, and enriched in metals (Cu, Au), but lack evidence for crustal assimilation. Field relationships indicate repeated intrusion of these fertile magmas into mid-crustal levels. Hornblende-dominated crystallization and fractionation led to successive batch segregation of granodiorite melt upon diorite recharge. Petrographic observations attest to hornblende textural breakdown during magmatic recharge, providing a mechanism for ore-fluid expulsion in the plutonic realm.

Item ID:	83434
Item Type:	Conference Item (Abstract / Summary)
Related URLs:	https://www.segweb.org/SEG-100/SEG-Confe...
Date Deposited:	27 Aug 2024 00:58
FoR Codes:	37 EARTH SCIENCES > 3705 Geology > 370502 Geochronology @ 50% 37 EARTH SCIENCES > 3705 Geology > 370508 Resource geoscience @ 50%
SEO Codes:	28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280107 Expanding knowledge in the earth sciences @ 100%
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