Programa de conferencias
Breccias in Epithermal and Porphyry Environment. Genetic styles and origins. A field outlook.
Mario AlfaroVice Presidente de Exploración @ Minera Sud Argentina SA
Exploration geologist and consultant geologist for international mining companies in Epithermal and Porphyry Systems. Competent Person in Mining Resources and Reserves, Fifty-one years (51 years) of experience in the mining industry, mines and exploration, mainly in the field of exploration of porphyry copper and epithermal gold deposits, exploration based on development of conceptual geological models. Competent Person (Qualified Persons). As an amateur mountaineer, great experience in work in remote regions and difficult terrain (high mountain range). Exploration Manager Fortuna Silver Mines Inc., Generation of New Projects. Gold Fields Peru Exploration Manager. Exploration Manager for Latin America at Metallica Resources. Expert Geologist United Nations Program (UNPD) Mexico, Compañía Minera Autlan, Chief Exploration Geologist. Chief of Geologists of the Department of Mineral Resources and Hydrocarbons of Honduras. El Salvador Codelco. Superintendent of the Department of Geology. Head of the Geology Department of the Los Bronces Mine of the Disputada de Las Condes. Disputed from Las Condes, Chief Geologist of the La Paloma-Sulfatos-Andina Project- Disputed
Resumen
The enigmatic breccia bodies correspond to a fragmental rock constituted mainly by clasts and matrix, but also by cement and, occasionally, spaces. The importance of breccias are not included in themselves, but rather define the processes and mechanisms involved in their formation (genesis) and, most importantly, their relationship with possible mineralization associated with porphyry and epithermal systems. Breccia bodies show various characteristics in their shape and composition, and for their field classification a system of registration and description is required by consensus in the team of geologists that allows their fundamental aspects to be clearly established, such as: (1) nature and composition of the fragments, (2) composition of the matrix, (3) characteristics and composition of the cement and (4) geometry and dimensions of the breccia bodies. Therefore, during the exploration stages, geologists must be able to distinguish the different types of breccias mapped in the field or in the drill core log, apply names to them, classify them, as a means of accessing the exploration meaning of many breccias, which are generated both in the early or late facies at the site of porphyry and epithermal deposits. In general, meteoric water cannot enter magmatic systems (early facies) since this systems, while they are active, they are usually hermetic. Towards the end of the magmatic activity, as its temperature dissipates and its internal pressure decreases, it is when external water could enter the system and generate the breach bodies. The presence of breccia bodies, with a great variety of characteristics, is common that accompanies a wide spectrum of reservoirs and often the breccias themselves constitute mineralized bodies. Therefore, it is important to understand the processes that generate breccia bodies associated with mineralization; which are the characteristics that allow distinguishing different types of them and describe the role of breccia in the formation of porphyry and epithermal deposits, all topics that will be addressed. in this conference.