SGA WORKSHOP ON GOLD IN THE EPITHERMAL ENVIRONMENT ORGANIZED BY THE BARCELONA STUDENT CHAPTER
2014 was a year full of timeless memories; enhancing experiences and knowledge broadening activities related to Ore Deposits. Given to last year’s success on the SGA workshop on mineral deposits related to acid magmatism, the enrollment of new members and the motivation of the entire Chapter, we were deeply enthusiast and encouraged to organize our third workshop, this time devoted to Epithermal Ore Deposits, from the 18th to 20th of September. It was held at the faculty of Geology of the University of Barcelona and counted with the total participation of 75 assistants, some of them even coming from Madrid and Granada. The aim of this workshop was to approach and provide a highly-developed survey about these deposits; the structure and formation of both high and low sulfidation epithermal deposits, their geochemistry, mineralogy, petrology and their economic interest to undergraduate, master, doctorate and young research students, as well as to professors, researchers and professional geologists, who were interested in these characteristic deposits and wanted to up-date their knowledge with the latest research on this topic.
The first day of the workshop consisted of a stimulating two-hour introductory class imparted by Antonio Arribas Jr, under the title of “Introduction to epithermal gold deposits and their classification”. This lesson was of great profit for students who were non-familiarized with this kind of deposit, due to its straight forward explanation and introduction to their basics. It included one hour of theory and another one of practical lesson, where members could learn how to recognize in hand sample the different alterations of high and low epithermal deposits (Fig. 1). Furthermore, petrographic microscope with reflective light was used to visualize the ores of these ones (Fig. 2). The samples used to carry out the practical lesson came from theFaculty of Geology’s wide collection and from Antonio Arribas itself, who kindly provided some of the spectacular samples he had the opportunity to pick up in the diverse deposits he had worked in.
The second day of the workshop held the enlightening lectures given by the invited speakers, recognized International experienced specialists on these type deposits (Fig. 3). Dr. Antoni Camprubí i Cano (Universidad Nacional Autónoma de México-UNAM) opened the session with “Mechanisms for ore deposition in epithermal depòsits”,throwing light upon the complex processes undergoing in these types of deposits, including boiling, conductive cooling, fluid mixing, etc. Moving on to more specific and detailed topics inside epithermal deposits, Dr. Antonio Arribas Jr. (Ann Arbor, Michigan), with his lecture entitled “Au-Ag-Cu high sulfidation epithermal deposits and their relationship to Cu-Au porphyry Systems”, illustrated the structure, alteration distribution and how high sulfidation processes relates to porphyry Systems. Emphasizing and making clear the difference between high sulfidation deposits and intermediate sulfidation ones, Dr. Antoni Camprubí i Cano (Universidad Nacional Autónoma de México-UNAM), declaimed again, but this time with a talk under the name of “How intermediate sulfidation epithermal deposits make sense”, also explaining in detail the characteristics which allows us to differentiate between them and depicting essential exploration guidelines. Finally, Dr. Isaac Corral Calleja (James Cook University, Australia & Universitat Autònoma de Barcelona), with a talk entitled “The Cerro Quema Au-Cu deposit, Azuero Peninsula (Panama): An example of a high sulfidation deposit in a fore-arc environment”, exposed the outcomes he obtained from this particular study case and described the experience he underwent whilst studying one of this type of deposits.
To enliven and offer a relaxed and friendly environment, an afternoon snack was provided at the Faculty’s courtyard after the conference sessions, consisting of diverse groceries, mojitos and the music our members bought in. Students enjoyed the opportunity to initiate a closer conversation and agreeable discussions with the attendants to the conferences, asking any doubts about the lectures and sharing their points of view.
On Saturday 20th, a one-day fieldtrip to different iron mines in Les Bordes de Conflent took place. Leaded by our PhD student member, Marc Campeny (Fig. 4), who acknowledged the mineral deposits of this region in Lleida, all attendants had great pleasure in listening to diverse explanations as the cause of mineralization in this area. Furthermore, we could distinguish copper sulfosalts (tennanite-tetrahedrite), arsenopyrite, pyrite and chalcopyrite mineralizations containing gold associated to shearing in the Pyrenees; the reasons why these mineralizations are largely classified as orogenic gold deposits were exposed and discussed (Fig. 5). In addition, attendants were delighted and extremely relished to take part in a fieldtrip to one of the most beautiful landscapes the Pyrenees offers us. Student members were greatly involved and the lecturers took great appreciation of this participation – leading to a wonderful atmosphere (Fig. 6). What’s more; we had the opportunity to find and pick up exceptional hand samples with idiomorphic tetrahedrite crystals, as well as acquire a full comprehension of functioning of the mineralized system.
We gratefully acknowledge all lecturers: Dr. Antoni Camprubí i Cano, Dr. Antonio Arribas Jr. and Dr. Isaac Corral Calleja for their overwhelming speeches, their deep motivation and interest in forming part of our third workshop, to everybody who was involved in it and gave us support. We also express our most true gratitude to the SGA for the economic support offered, which allowed us to develop and carry out successfully all our activities. We would also like to thank the Faculty of Geology for their logistic and economic support, as well as to the SEG, for its collaboration in the process of organization.
