Geological side of High Tech Metals

In connection with the exhibition about Hight Tech Materials held at our Faculty, the BCN_SGA Student Chapter organizes this activity on Wednesday February the 12th. It will consist of several talks devoted to a better understanding of the geological side of these materials.

The activity is thought as a plain explanation of the importance of these elements and materials as essential for our society. The geological setting of convencional and non-convencional deposits will be introduced. The activity will close with a promising debate entitled Mining YES/NO.   

Talk by José María González: ORIGINS OF PLATINUM-GROUP MINERALS IN UPPER MANTLE ROCKS

Title: Origins of platinum-group minerals in upper mantle rocks

Lecturer: Dr. José María González Jiménez (Geochemical Evolution and Metallogeny of Continents (GEMOC); Dep. Earth and Planetary Sciences; Macquarie University, Australia).

Date: Tuesday January the 07th, 2014 at 16:00h

Place: Room 11

Abstract: 

In the upper mantle, the platinum-group elements reside mainly in specific minerals known as the platinum-group minerals (PGMs), and to a lesser extent dissolved in base-metal minerals (including Fe-Ni-Cu sulfides, arsenides) and alloys. They vary widely in distribution, morphology, and chemistry and Os-isotope compositions, suggesting different possible origins. The remarkable abundance of these minerals in chromite-rich rocks may reflect the role of chromite as a physical “collector” of the platinum-group elements during crystallisation of both phases from melts. However, despite a great body of work, the links between the PGMs (and their associated base-metal minerals) and the mechanism of formation of their host chromitites are still unclear and hotly debated. Platinum-group minerals found in the upper mantle chromite-rich rocks show significant Os-isotope heterogeneity on the scale of single micrometric grains enclosed within individual chromite grains. This micro-scale isotopic heterogeneity, and their random spatial distribution within the chromites, argues strongly against an origin of the platinum-group minerals via exsolution from the chromite lattice during post-magmatic cooling. A re-interpretation of their microstructures and Os isotopes analysed in situ had led us to review the traditional models, and to propose several origin(s) for the platinum-group minerals in chromitites. (1) The suites of platinum-group minerals mainly record crystallisation during mixing of multiple different melts and physical entrapment in chromite. (2) Some platinum-group mineral sin chromitites may have been scavenged from wall-rock peridotite during migration of the parental melts of the chromitite. (3) Other platinum-group minerals may have precipitated from metasomatic fluid/melts that infiltrated existing chromitites. The recrystallization of pre-existing platinum-group minerals during polyphase metamorphism or “recycling” of the chromitite into deeper mantle levels can explain the presence of micrometric platinum-group minerals with distinct Os-isotope compositions, associated with minerals such as chlorite.

URANIUM WORKSHOP IN NANCY

Our colleagues from Nancy organized a workshop about Uranium that took place in Nancy on December 12-13th, 2013. Many participants from all over the world attended the workshop.

Belén Torres Cueva, member of the Barcelona SGA Student Chapter participated in the workshop as representative of our association. Belén, recently graduated, is about to commence the Master in Geology and Environmental Management at the University of Huelva.

During the first day of the workshop, talks started with an introduction about the uranium cycle over time followed by the exposition of examples of some important uranium deposits in the world. During the day there was also time for coffee breaks, lunch and an interesting poster session.

The second and final day of the Uranium Workshop, two PhD students exposed their researches. One was about the cycle of uranium and the tectono-metamorphic evolution of the Pan-African orogenic belt of Lufilien (Zambia) and the other session was about The formation of Roll-front deposits in the Erlian basins, China.

This amazing Uranium Workshop concluded with a refreshment and lunch.

FIELDWORK IN THE DOMINICAN REPUBLIC

During three months, Lisard Torró, our president, has developed a fieldwork campaign in the Dominican Republic thanks to a grant awarded by the SEG (Society of Economic Geologists).  This work is part of his PhD Thesis research about the metallogeny of metallic deposits in Cordillera Central in this country.

The main part of the stay was devoted to developing a detailed mapping and sampling in the Los Ranchos Formation materials close to Cotuí city area; with the purpose of finding the fresher outcrops, several tens of rivers and arroyos were gone over, machete in hand. The other part of the campaign was developed in the Cerro Maimón mine and surroundings and consisted of both fieldwork along several rivers and the logging and sampling of drill cores from new prospects in Maimón Fm. and Bayaguana areas.

During his stay, Lisard taught two subjects at ITECO, the unique university of the country with a program in Geology. A total of 42 students had to bear his lessons!

Júlia Farré, a last-year student of Geology at UB and the 4th year Student Committee of our Student Chapter, had also the opportunity to work in Dominican Republic in order to develop the fieldwork related with her Final Degree Thesis about the petrology and geochemistry of the most deformed rocks in the Maimón Formation; this Formation hosts the Cerro Maimón mine, currently the only VMS deposit under production in the Caribbean. During the week she spent there, a comprehensive field and core sampling was carried out.

Both insist to stress their gratitude to all collaborators (SEG, CORMIDOM-PERYLIA, EVERTON and individuals) that allowed them to develop an essential part of their research as well as, although the hard work carried out, to live a superb vital experience.

Antonio Arribas Moreno-Honorific Advisor of the BCN-SGA Student Chapter

During the second workshop organized by the BCN-SGA Student Chapter (University of Barcelona, 19th-21st September 2013) a well-deserved homage to Antonio Arribas Moreno was celebrated, to honour his career and his contribution to the study and research in the field of mineral deposits.

Antonio Arribas Moreno was born in Madrid in 1922. He obtained the degree of Natural Sciences in 1948 and afterwards he graduated in Economic Geology in 1961 in the University of Madrid.

Even so, his entire academic career was developed at the University of Salamanca where he founded the department of Crystallography, Mineralogy and Ore Deposits in 1965 – the first official Ore Deposit department settled in the Iberian Peninsula. He was the dean of the School of Sciences from 1970 to 1987 as well as the director of the Spanish Institute of Applied Geology from 1980 to 1987.

During his academic life he directed more than 125 final degree projects and around 35 PhD Theses, and worked with people from all around the globe.

Antonio, without a doubt whatsoever, is one of the fathers of Ore Deposit research in the Iberian Peninsula and other territories such as the Western Sahara, where he supported until very recently several field investigations in collaboration with students and professors from the University of Barcelona.

For all these reasons together with his kind personality and neverchanging young soul we are extremely pleased to present Antonio Arribas Moreno as the Honorific Advisor of the BCN-SGA Student Chapter.

Welcome Antonio! 

Talk by Antoni Camprubí: IOCG deposits in Mexico: more questions than answers?

Title: IOCG deposits in Mexico: more questions than answers?

Lecturer: Antoni Camprubí (Centre of Geosciences and the institutes of Geophysics and Geology-UNAM)

Date: Thrusday October 31st 2013. 13:00h

Place: Room 2

Abstract: Magmatic-hydrothermal iron oxide deposits, or IOCG "clan", are a group of ore deposit types that formed in a wide range of tectonomagmatic environments and depths of emplacement: from intra-arc or back-arc environments to those related with anorogenic magmatism (even in association with carbonatites), and from near-surface to deeper than 10 km deposits. The occurrence in Mexico of these deposits spans from Lower Cretaceous to Miocene examples, whose minimum distance from their respective hypothetical subduction trenches in the Pacific convergent margin suggests the existence of at least two groups of IOCG types of deposits from the tectonomagmatic standpoint.

On the one hand, there is a large amount of these deposits located near the edge of the present Pacific coast, running from the Baja California peninsula to the state of Chiapas. Such distribution is very similar to that of similar deposits in the Andean coastal ranges, and suggests that their formation might have occurred in a similar setting, likely to be due to extensional intra-arc magmatism. The latter would have fringed the buildup of continental crust prior to and simultaneously to part of the Laramide orogeny (~80 a 40 Ma), which ultimately deactivated the formation of IOCG deposits and led to the formation of other types of ore deposits.

On the other hand, many other IOCG deposits are clearly distal to the Pacific margin before the Baja California rift-off, between ~500 and ~1000 km inland. Such is the case of the Eastern Mexican Alkaline Province (EMAP), which formed entirely in the Cenozoic and also contains carbonatites. This feature suggests additional tectonomagmatic environments for IOCG formation in Mexico, which also occur in the Cordillera of Western North America, but not in the Andes. The EMAP as a whole poses an interesting topic for further research in the metallogeny of Mexico, as its tectonomagmatic setting remains ill-defined to date.

Talk by Carl Nelson: Hot Spring Gold Deposits of the Circum-Pacific Region

Title: Hot Spring Gold Deposits of the Circum-Pacific Region

Lecturer: Carl E. Nelson (Recursos del Caribe SA)

Date: Thrusday October 17th 2013. 11:00A.M.

Place: Room 7

Abstract: There are currently about a dozen gold deposits that exhibit evidence for an origin at or directly beneath the paleo-surface. Collectively referred to as “Hot Spring” deposits, they were first recognized in 1980 with the discovery and recognition of a near-surface origin for the McLaughlin gold deposit (3.2 Moz) in California. Since then, additional discoveries have been made and unequivocal evidence for a hot spring origin has been recognized at other gold deposits in the Circum-Pacific region. Such evidence includes silica sinter, deposited originally as amorphous silica in hot spring pools and terraces, and, aprons of hydrothermal eruption debris which thicken and coarsen toward a central hydrothermal eruption vent. Mineralization typically consists of microcrystalline quartz, minor adularia, several percent pyrite-marcasite and native gold hosted by central, higher-grade, hydrothermal vent breccias and surrounding, lower-grade, quartz vein stockworks. A blanket of advanced argillic alteration, consisting of cristobalite - alunite – kaolinite is superimposed, when present, on ore-bearing sulfidic silicification. Precious metal mineralization in hot spring deposits is the result of shallow boiling of the hydrothermal fluid. Episodes of high fluid throughput steepen the pressure gradient in fossil geothermal systems, raise the boiling level to near grassroots levels and result in shallow precious metal mineralization along with a steeply zoned suite of associated “pathfinder” elements (Sb, Hg, Tl).

SGA WORKSHOP ON MINERAL DEPOSITS RELATED TO ACID MAGMATISM

Due to the success of the first workshop devoted to pegmatites organized by the Barcelona Student Chapter a year ago, a second workshop was planned for the days 19th to 21st of September of this year. In this occasion the topic was the ore deposits related to acid magmatism.

The workshop, held at the Faculty of Geology of the University of Barcelona, was addressed to students and young researchers interested in this type of ore deposits, as well as to professors, researchers and professional geologists who wanted to increase their knowledge and be up to date of the latest research on this topic. Therefore, the aim of this workshop was to provide an advanced overview of mineral deposits related to acid magmatism, including mineralogy, textures, petrology, geochemistry and economic interest of these deposits.

The workshop included an enlightening two-hour introductory lesson entitled “Felsic magmatism and hydrothermal systems” kindly given by Prof. Bernd Lehmann (Technical University of Clausthal – Germany).

The main day of the workshop consisted of a one-day session of lectures given by international experienced specialists on this topic. Thus, the talk by Prof. José Mangas (Universidad de las Palmas de Gran Canarias – Spain), entitled “Spanish Sn deposits associated to Hercynian granitic intrusives” explained the three stages of formation registered in the Spanish deposits deduced from the fluid inclusion study; Prof. Mangas also emphasized the economic potential of tin mines, most of them closed, in countries such as Spain, Portugal, Germany or the Czech Republic. Prof. Fenando M.P. Noronha (Universidade do Porto) moved from tin to tungsten deposits with the talk entitled “Tungsten ore deposits in Central Iberian Zone”; all the audience could enjoy his talk in which the Panasqueira mine was clearly the main focus. Prof. Bernd Lehmann (Technical University of Clausthal – Germany), with his talk “Granite-related rare-metal mineralization”, explained the geochemistry of the tin and the tantalum in the magmatic-hydrothermal system and the concentration mechanisms. Finally, Dr. Hildebrando Leal-Mejía (University of British Columbia - Canada) explained the evolution of the   Phanerozoic acid magmatism in the Colombian Andes and its relationship with Gold Deposit genesis.

At the end of the conference session, homage to Prof. Antonio Arribas Moreno was held. The act, leaded by Prof. José Mangas, served for introducing this important personality in the world of the mineral deposits to those who did not know his very active and complete scientific live. Prof. Antonio, who is now 90 years old, kindly attended our workshop. Some personalities such as Prof. Fernando Noronha and Dr. Joan Carles Melgarejo took advantage of the homage to publicly thank Prof. Antonio for their support during the development of their scientific careers.  Some videos of people who could not attend the workshop were reproduced, such as those recorded by Saleh Lehbib (PhD student from the Sahara Occidental) and Prof. Antonio Arribas Jr. (president of the SEG and son of Prof. Antonio Arribas Moreno). Finally, Prof. Antonio Arribas Moreno was proposed as Honorary Advisor of our Student Chapter. After he accepted (with pleasure, according to his words) this position, we are so pleasured and honored of announcing that Prof. Antonio Arribas Moreno is now our Honorary Advisor.

Additionally, a fieldtrip leaded by Dr. Joan Carles Melgarejo, advisor of the Barcelona Student Chapter, to the Barberà Basin (Conca de Barberà) took place. During this one-day fieldtrip the attendance could observe the quartz-wolfram veins in hercinian granitoids, polymetallic sulphide mineralisations (Pb-Zn-Cu-Au-PGE-Bi-Te-As-Ni-Co-V-Cr), barite veins and XVIth century alum mines. Mineralogical and petrographical aspects of the ores and host rocks were combined with geochemistry, fluid inclusion data and large-scale tectonics, in order to have a broad view of the visited ore deposits and their environment.

We hope that you all enjoyed the workshop.