US EPA

6870314 

Journal Article 

Hydrothermal alteration, SWIR-mineral mapping, vein distribution and age of the Haquira East porphyry Cu-Mo deposit 

Cernuschi, F; Dilles, JH; Creaser, R; , 

2013 

SGU-SVERIGES GEOLOGISKA UNDERSOKNING-GEOLOGY SURVEY SWEDEN 

UPPSALA 

782-785 

WOS:000337983900197 

The Haquira East porphyry Cu-Mo deposit has Re/Os and Ar-40/Ar-39 ages of similar to 33.8 to 33.2 Ma. The ores are hosted in the Haquira granodiorite porphyry stock that intruded a connpressionally deformed sequence of Mesozoic quartzite, meta-siltstone, and minor marble in the Andahuaylas-Yauri porphyry belt of southern Peru. New core logging observations, geochemical data, cross-sections, petrography and SWIR-scan images of hydrothermally altered samples document the vein sequence and alteration mineralogy. From oldest to youngest, the sequence consists of aplite dikes, barren quartz-K-feldspar veins, biotite micro-breccias/veins, actinolite veins with plagioclase halos and epidote veins, EDM-type dark and pale micaceous halos with bornite-chalcopyrite, A quartz veins with bornite-chalcopyrite, quartz-molybdenite veins, B quartz-bornite-chalcopyrite veins, D pyrite-quartz veins with sericitic halos, and snnectite-chlorite-kaolinite +/- pyrite halos. The distribution of both Cu-sulfide and Mo-bearing veins forms an inverted cup-shaped volume or shell above a core zone of high density aplite and barren quartz-K-feldspar veins. The copper shell forms a continuous high-grade ore zone in the Haquira stock, but is low grade where it projects into the relatively non-reactive quartzites, likely as a result of a limited supply of iron to enable copper-iron sulphide precipitation. In contrast, molybdenite mineralization forms a roughly symmetric shell overlapping both stock and quartzite with an axis of symmetry located along the southwest contact of the Haquira stock. 

Jonsson, E; 

978-91-7403-207-9 

12th Biennial SGA Meeting on Mineral Deposit Research for a High-Tech World 

Uppsala, SWEDEN