Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Geology and alteration geochemistry of the porphyry Cu-Au-deposit at Bajo de la Alumbrera, Argentina

Thomas Ulrich and Christoph A. Heinrich
Geology and alteration geochemistry of the porphyry Cu-Au-deposit at Bajo de la Alumbrera, Argentina
Economic Geology and the Bulletin of the Society of Economic Geologists (December 2001) 96 (8): 1719-1741

Abstract

This world-class porphyry Cu-Au deposit occurs in the K-rich calc-alkaline Farallalon Negro volcanic complex in NW Argentina, 200 km E of the main Andean porphyry belt of Chile. It consists of a composite stock of dacite porphyry intrusions and extends into the surrounding andesitic rocks. Two of the intrusions in the centre of the complex show intense hydrothermal alteration and mineralization. Intense quartz-magnetite alteration pervades the first mineralized porphyry, whereas lower intensity alteration affected the second; this alteration grades laterally into potassic alteration (secondary K-feldspar and biotite). An outer halo of propylitic alteration extends up to 1 km into the andesites. Feldspar-destructive alteration (sericite + pyrite + or - clay minerals + or - gypsum) overprints the potassic and propylitic alteration in the volcanic rocks and all porphyries. Cu and Au are intimately associated on all scales; they occur as gold sulphide grains (chalcopyrite, rarely bornite). The bulk of the ore minerals now occupy texturally late positions in vugs and fractures.


ISSN: 0361-0128
EISSN: 1554-0774
Coden: ECGLAL
Serial Title: Economic Geology and the Bulletin of the Society of Economic Geologists
Serial Volume: 96
Serial Issue: 8
Title: Geology and alteration geochemistry of the porphyry Cu-Au-deposit at Bajo de la Alumbrera, Argentina
Affiliation: ETH Zuerich, Isotope Geochemistry and Mineral Resources, Zurich, Switzerland
Pages: 1719-1741
Published: 200112
Text Language: English
Publisher: Economic Geology Publishing Company, Lancaster, PA, United States
References: 51
Accession Number: 2002-014795
Categories: Economic geology, geology of ore deposits
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Includes appendix
Illustration Description: illus. incl. sects., 4 tables, geol. sketch maps
S27°30'00" - S27°30'00", W67°00'00" - W66°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Update Code: 200206
Close Modal

or Create an Account

Close Modal
Close Modal