2015 Closure Event

2015 academics’ year ending consisted in diverse outstanding talks given by both undergraduated and graduated students (Phd). Lisard Torró presented Weathering Profile of The Cerro de Maimón Vms Deposit (Dominican Republic): Textures, Mineralogy, Gossan Evolution and Mobility of Gold and Silver in Pope for an hour session, whilst numerous other students gave a short and intensive 10 minutes talks in english:

Daniel Rodríguez with “Au mineralisation in listvenites from a serpentinisedophiolite complex in Mina Descanso (Central Cuba)”, Mariona Tarragó with “Diffusion of heavy metals during vitrification of chromium sludge in a basaltic matrix: model of a melting pond in an alumina crucible”, Miriam Pastor with “The San José-Itos mines, Oruro, Bolivia: Structure and Ag-Sn Mineralization”, Lisard Torró with  “Geochemistry of the VMS bearing Maimón Fm. (Central Cordillera, Dominican Republic): assignation to a fore-arc environment in a nascent intraoceanic island arc”, Cristina Villanova with “Ni-enrichment processes revealed by TEM imaging on garnierites”, Clara Román Alday with “The Romero Cu-Au-Zn deposits, Cordillera Central, Dominican Republic: Preliminary data on the mineralogy and geochemistry of mineralization”.

These presentations consisted in the exposition of final degree Projects (TFG), final master Projects (TFM) and even other post-master research projects, all of them resulting in succesful talks which enhaced motivation and participation within attendants. After these sessions a coffee stand was displayed and every participant could enjoy the company of our collegues and bid farewell to our friends before entering the forecoming summer. 

     

 

Weathering profile of the Cerro de Maimón VMS deposit (Dominican Republic): textures, mineralogy, gossan evolution and mobility of gold and silver.

 

Lecturer: Lisard Torró

Date: Wednesday the 8th, 10.00h

Place: Room 2, Fac. Geology UB

Abstract:

Cerro de Maimón, in the central Dominican Republic, is currently the only VMS deposit under production in the Caribbean region. It is hosted in the Maimón Formation, of early Cretaceous age, which is part of the oldest and chemically most primitive island-arc in the Caribbean. From bottom to top, this deposit can be divided into (i) a primary sulfide zone, (ii) a supergene enrichment zone and (iii) an oxidized zone. This study reports new data on the textural and mineralogical characteristics of the oxidized zone (gossan/leached capping zone) with emphasis in the Au-Ag-bearing phases. The mineral paragenesis of the oxidized zone is essentially composed of goethite, hematite, quartz and barite. Botryoidal, cellular and brecciated textures can be distinguished. Botryoidal and brecciated textures dominate in the upper parts of the oxidized zone, whereas cellular textures are more common in the intermediate and lower parts. However, the weathering profile is very heterogeneous. The leached capping profile shows evidence of both transported and indigenous gossans. Gold in the oxide paragenesis is extremely pure (99% Au) suggesting that chemical refining took place. Silver occurs mainly as iodargyrite (AgI), and minor AgBr, AgCl, in botryoidal aggregates.

Particles of Au-Ag alloy in the primary mineralization exposed to a weathering environment can be leached and transported by various agents (chemical and biochemical) that may exist simultaneously. In the presence of halides, gold and silver can be leached and transported in a wide range of pH-Eh conditions, especially if iodine is present. Silver is leached more rapidly and over a broader range of pH-Eh conditions, and is preferentially transported as iodine-complexes than other halides. The presence of iodargyrite in the Cerro de Maimón gossan, fully developed under tropical conditions, suggests that this mineral cannot be considered an indicator of extremely arid environments as typically claimed by many authors; iodargyrite occurrence would rather point to the presence of saline-halide rich groundwater in oxide deposits.

Aplicación de los isótopos estables en el estudio de los dipósitos minerales (Application of stable isotopes in the study of ore deposits).

Lecturer:Dr. Esteve Cardellach López

Date: Thursday  March the 5th, 15:00-17:30h

Place:Room 4

Abstract: The talk began with a brief overview, as a reminder, on the theory of isotopic equilibrium systems most frequently applied to the study of mineral deposits, namely isotopes of S, C, O and H. Dr. Cardellach pointed out the particularities and the information that provides each of these isotopes and isotopic pairs, focusing on its application for the identification of the origin of mineral fluids.

In addition to theoretical considerations, Cardellach exposed a number of real examples applied to the study of deposits. Some of these examples included: wolframite deposits of Panasqueira (Portugal), Pb-Zn deposits associated to diapirs in the Basque-Cantabrian Basin, Pb-Zn deposit MVT type of San Vicente (Peru), Zn-Pb-Ag deposit Sedex type of HYC McArthur River  (Australia) and veins of Ba-F-Pb-Zn of Atrevida vein (NE of the Iberian Peninsula, Spain).

Biografical summary:Dr. Cardellach is former professor and researcher of Mineralogy and Mineral Deposits at the Geology Department (Universitat Autònoma de Barcelona (UAB)). Great part of his research has been focused on the origin and evolution of mineral fluids. During his professional career has made research stays to Durham University and Yale University, where he worked on the geochemistry of stable isotopes.

Recently he has been principal investigator on several research projects, the latest of which dealt with the study of epithermal Au deposit at Cerro Quema, Panama. Currently, Cardellach is involved as researcher in a project led by the Universidad de Huelva (Spain) on Black Shales and massive sulfide deposits.

 

Acid waters in Antartica

Title: Acid waters in Antartica

Lecturer: Bernarth Dold

Date: Tuesday February the 24th 2015, 17 hs.

Place: Room 4.

Abstract:  Bernarth Dold is specialized in biogeochemical and hydrogeological processes controlling element cycles in ground and surface waters, soils, industrial waste environments, bioleaching operations, and ore formation.

Acid waters are mainly due to the interaction between groundwaters of different geological units containing significant amounts of massive metal sulfides by oxidation and dissolution processes in warm climates.  As an example; the pyrite oxidation:

FeS2 (Pyrite) +3 ½O2 + H2O   à  Fe2+ + 2SO42- + 2H+

But how can acid waters be formed in Antarctica? Massive sulphide oxidation in cold climates has been scarcely studied, but it is known that these kinds of waters exist. Would their impact on local species be positive or negative?

Expeditions to Antarctica have been performed to study both the biogeochemical cycling of iron and sulfur, in which has been observed a biogeochemical reduction process; Fe (III) to Fe(II), generated by microorganisms and submarine groundwater discharge.

Concluding:

-          The study undergone allowed us to understand the relationship between this phenomenon and the effect of the contribution of limit elements of the ocean food chain.

-          Research on sulphide oxidation in an extreme climate could help understanding the origin of life and the possibility of finding it in other planets.

-          Knowledge on this topic would be useful for mining operations located in cold areas like high Andes.

 

Talk by Professor Carl E. Nelson, consulting economic geologist.

Title: Genetic Models for the Pueblo Viejo Au-Ag-Cu-Zn district, Dominican Republic.

Lecturer: Carl Nelson.

Date: Monday Novembre the 3st 2014, 13hs.

Place: Room 2.

Abstract: The origin of the Pueblo Viejo deposit has long been a subject of debate. Published models refer to Pueblo Viejo as a Tertiary porphyry copper deposit (Hollister, 1978), a Cretaceous epithermal deposit (Kesler et al., 1981), a Cretaceous maar-diatreme (Sillitoe and Bonham, 1984; Russell and Kesler, 1991); a Cretaceous high sulfidation deposit (Sillitoe et al., 1996), a Cretaceous volcanic dome field (Nelson, 2000a); and a Tertiary porphyry copper lithocap (Sillitoe et al., 2006).  A link to VMS deposits is supported by the presence in the Moore pit of massive sulfide layers adjacent to a baked intrusive contact with a dacite volcanic dome (Nelson, 2000b). Surrounding mineral occurrences include both traditional bimodal mafic massive sulfide deposits and epithermal deposits with high sulfidation mineral assemblages similar to Pueblo Viejo (Nelson, 2000). Pueblo Viejo is perhaps best described as a hybrid deposit, with both epithermal and VMS characteristics, in effect, a submarine volcanogenic massive sulfide that formed at shallow depth. 

 

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.

SGA WORKSHOP ON GOLD IN THE EPITHERMAL ENVIRONMENT

We are yearning to announce you this year's workshop about epithermal deposits! You can find all information about the workshop here.  We are looking forward to seeing you in Barcelona!   

SGA WORKSHOP ON GOLD IN THE EPITHERMAL ENVIRONMENT

PROGRAM

September the 18th 2014 (room 12)

18:00h- Dr.Antonio Arribas Jr. (Ann Arbor, Michigan): Introduction to epithermal gold deposits and their classification (Introducción a los yacimientos epitermales de oro y su clasificación)

September the 19th 2014 (Aula Magna)

08:30h- Welcome coffee + registration.

09:45h- Presentation of the new SEG-SGA mixed student chapter in Barcelona

10:00h- Dr. Antoni Camprubí i Cano (Universidad Nacional Autónoma de México-UNAM): Mechanisms for ore deposition in epithermal deposits (Mecanismos de deposición de menas en los depósitos epitermales)

11:00h- Dr. Antonio Arribas Jr. (Ann Arbor, Michigan): Au-Ag-Cu high sulfidation epithermal deposits and their relationship to Cu-Au porphyry systems (Los yacimientos epitermales de alta sulfuración de Au-Ag-Cu y su relación con los sistemas pórfido Cu-Au)

13:00h- Lunch

15:00h- Dr. Antoni Camprubí i Cano (Universidad Nacional Autónoma de México-UNAM): How intermediate sulfidation epithermal deposits make sense (Cómo los depósitos epitermales de sulfuración intermedia tienen sentido)

16:15h- Coffee break

16:30h- Dr. Isaac Corral Calleja (James Cook University, Australia & Universitat Autònoma de Barcelona): The Cerro Quema Au-Cu deposit, Azuero Peninsula (Panama): An example of a high sulfidation deposit in a fore-arc environment (El depósito de Au-Cu de Cerro Quema, Península de Azuero (Panamá): un ejemplo de depósito de alta sulfuración en un ambiente de ante-arco)

18:00h- Luncheon, music and beer at the faculty’s patio

September the 20th 2014

08:00- FIELD TRIP (meeting point: Faculty of Geology)

Workshop fieldtrip to Les Bordes de Conflent

The fieldtrip of the III SGA BCN-Student Chapter Workshop will be carried out in the heart of the Pyrenees. We will visit the iron mines of Les Bordes de Conflent, where it is also possible to distinguish an orogenic gold mineralization associated to copper sulfosalts (tennanite-tetrahedrite), arsenopyrite, pyrite and chalcopyrite.

Our colleague Marc Campeny, who has a good knowledge of the region, will guide this fieldtrip.

We will meet at the Faculty of Geology the 20/09/2014 at 06:30 am.

The price for SGA Student members is of 10€ and for non SGA Student members of 20€. Here you can download the registration form.

And remember, the number of attendants is limited to 25!!

2013-2014 end of term Party

The last July 18th our Student Chapter has the End-of-term party. In this party the students gave several talks related to ore deposit topics. The talks were prepared in English and were about 10 minutes long. The aim of these talks is to improve the skills in English speaking and to prepare for future meetings were probably we will have to present our own research.

The talks presented were:

-          Clara Roman: Textures, mineralogy and geochemistry of the epithermal mineralization of the Romero gold-copper prospect, Las Tres Palmas district, Dominican Republic

-          Anna Mireia Rebaza: Diamonds on the white continent

-          Núria Pujol: HEAVY ELEMENTS ENRICHED PYRITE: the Dominica Island example

-          Cristina Villanova: Ni-phyllosilicates as seen under TEM: processes of Ni enrichment

-          Merlí Oliveras: The mines of the Collada Verda (Ripolles, Pardines): geological mapping, structure and mineralogy

We have to congratulate all the participants because the talks were very well prepared and very interesting.

Finally we had lunch together and Cristina brought us a wonderful and tasting cake!

THE BCN SGA STUDENT CHAPTER: a flexible training model as response to the current needs

On July the 2nd 2014, our Student Chapter presented a communication in an international meeting about university teaching and innovation, specifically in the field of student participation. The congress, under the name of CIDUI (International Congress of University Teaching and Innovation), held in Tarragona (Catalonia), was devoted to “flexible training model as response to the current needs”.

The talk entitled “THE BCN-SGA STUDENT CHAPTER: A tool for insertion to research and laboral world in metallogeny” was presented by three student members: Sandra Baurier, Teresa Baraza and Núria Pujol.

Different attendants became interested in this student initiative that can provide a broader formation of students and opportunities for their insertion in the professional world; the three students presenting the communications were congratulated for the work developed by the student chapter so far.

POPE FOR AN HOUR: CRISTINA VILLANOVA-DE-BENAVENT

Title: Garnierites and garnierites: Textures, mineralogy and geochemistry of garnierites in the Falcondo Ni-laterite deposit, Dominican Republic

Lecturer: Cristina Villanova-de-Benavent

Date: Wednesday June the 18th 2014, 12.00h

Place: room 2

Abstract: Garnierites (Ni–Mg-bearing phyllosilicates) are significant ore minerals in some Ni-laterite deposits. In the Falcondo deposit (Dominican Republic), garnierites are found as fracture-fillings and coatings on joints. Different greenish colours and textures can be distinguished, which correspond to different mineral phases, defined according to X-ray diffraction (XRD) and electron microprobe (EMP) analyses: a) talc-like, b) serpentine-like, c) a mixture of talc- and serpentine-like, and d) sepiolite-like. Compositional data indicate continuous Mg–Ni solid solution along the joins lizardite–népouite, kerolite–pimelite and sepiolite–falcondoite. EMP analyses showing deviations from the stoichiometric Mg–Ni solid solutions of serpentine and talc are best explained by talc- and serpentine-like mixing at the nanoscale. A detailed textural study by means of quantified X-ray element imaging provides a wealth of new information about the relationships between textural position, sequence of crystallization and mineral composition of the studied garnierite samples. These results indicate several stages of growth with variable Ni content, pointing to recurrent changes in the physical–chemical conditions during garnierite precipitation. In addition, our detailed mineralogical study of the Falcondo garnierites revealed that the different types identified have characteristic H2O content and SiO2/MgO ratios, which play important roles during the pyrometallurgy process.

For further information: Villanova-de-Benavent, C., Proenza, J.A., Galí, S., García-Casco, A., Tauler, E., Lewis, J.F., Longo, F. (2014): Garnierites and garnierites: Textures, mineralogy and geochemistry of garnierites in the Falcondo Ni-laterite deposit, Dominican Republic. Ore Geology Reviews, 58, 91-109

Pope for an hour are talks given by student members of the Barcelona SGA Student Chapter about their recently published research in SCI journals. These talks are adressed to other undergraduate or graduate students as well as to the rest of the scientific community.