Arizona Geological Society
2025 Speaker Series
Tuesday, 4 November 2025 | 5:30 - 8:00 PM
Location: Hexagon Mining Division Office
40 East Congress Street, Suite 150, Tucson, Arizona 85701
Parking: On the street or parking garage (Old Pueblo Parking)
Social Hour - Sandwiches from Beyond Bread (5:30-6:25 PM MST), Presentation (6:30 PM MST)
AGS Publications will be available for sale at Tuesday's meeting.
Will need cash or check (no credit cards)
For those planning to attend the event, please register by 6:00 PM on Sunday, November 2, 2025
Livestream URL Pending
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The Arizona Geological Society thanks Hexagon
for generously providing the venue and drinks
Ore Characterization, Spatial Distribution, and Genetic Implications of the Mineralization in the Filo del Sol Porphyry-Epithermal Cu-Au-Ag System, Central Andes (Argentina-Chile)
Camila Sojo1 and Hervé Rezeau 1,2
1 Department of Geosciences, University of Arizona, Tucson, AZ
2 MIT Earth Resources Laboratory, Massachusetts Institute of Technology, Cambridge, MA
Abstract: Filo del Sol (FDS) is a highsulfidation Cu–Au–Ag epithermal deposit overprinting a porphyry Cu–Au system, located within the Vicuña Metallogenic Belt between the world-class Maricunga and El Indio Cu–Au–Ag belts in the Central Andes. In this presentation, I will integrate detailed petrographic observations with in-situ elemental and isotopic analyses of sulfides, sulfosalts, and sulfates of four main exploration targets (Filo, Aurora, Refugio, and Bonita; Fig. 1), highlighting the complex evolution of mineralization styles across the deposit. High-sulfidation Cu–Au–Ag mineralization is characterized by pyrite, enargite, tennantite, Cu-sulfides (covellite, chalcopyrite), and a variety of Ag–Cu sulfosalts associated with acid-sulfate alteration (quartz–alunite–kaolinite). In contrast, the deeper porphyry Cu–Au mineralization is less complex and consists of pyrite, chalcopyrite and minor bornite ± digenite associated with potassic alteration (secondary K-feldspar, biotite, magnetite). Our results reveal a complex, multistage mineralizing history from porphyry Cu–(Au) mineralization to high- and intermediate sulfidation Cu-Au-Ag mineralization stages, magmatic–hydrothermal breccia events and supergene Cu enrichment. A special emphasis will be given on pyrite (± other ore minerals) textures and chemistry as it represents key archives of evolving fluid conditions and sources throughout this sequence. Importantly, the Aurora target emerges as the main feeder zone of the system, hosting the most significant mineralization and recording the porphyry epithermal transition with multiple breccia events. Laterally, Filo and Refugio targets reflect genetically related mineralization through fluid cooling pathways from Aurora, whereas the northern Bonita area displays distinct characteristics indicative of a more distal, intermediate sulfidation environment.
Top: Alteration Map for Filo del Sol Project, on red line are indicated the boundaries between target areas. Bottom,NNE-SSW field view (indicated with black arrow in alteration map). Photo Credit: Guido Merino (MSc Student at U of A).
Bio: Camila is a 4th-year PhD candidate at the Department of Geosciences in the University of Arizona working under the supervision of Dr. Hervé Rezeau (MIT Earth Resources Laboratory, and former Lundin chair in Economic Geology at the University of Arizona). She earned her B.S. degree at Universidad Nacional de San Juan in Argentina (2017) and spent nearly four years exploring porphyry copper deposits in the Central Andes with the mining company Fortescue. Camila was awarded the competitive Fulbright Scholarship to begin her PhD studies at the University of Arizona.
Her academic interests include economic geology, mineralogy, geochemistry, and field geology, as well as GIS and remote sensing analysis. Her current doctoral research focuses on understanding the magmatic hydrothermal evolution and ore distribution of the Filo del Sol Cu–Au–Ag porphyry-epithermal system, located in the Central Andes of Argentina. To address key research questions at Filo del Sol, she applies a multidisciplinary approach that includes field-based observations, petrography, geochronology, mineral elemental and isotopic geochemistry.
In August 2024, Camila was recognized with one of the four Best Student Presentation awards at the Society for Geology Applied to Ore Deposits (SGA) conference for her research on Filo del Sol.
Hexagon Mining Division Office - 40 East Congress Street,
Suite 150, Tucson, Arizona 85701
