“Disseminated & Veined Epithermal Silver Mineralization: Santo Domingo Deposit, Jalisco, Mexico ”
by Stew Fumerton, Ph.D. P.Geo., Calgary
The Santo Domingo deposit is hosted in volcanic and sedimentary rocks which form part of the southern end of the Sierra Madre Occidental. Mineralization is controlled by southeastnorthwest faulting which are part of the Tepec-Zacoalco Rift System and the mineralization is overlain by Trans-Mexican Volcanics. The Tepec-Zacoalco Rift System forms the northern boundary of the Jalisco Block which is drifting away from the North American plate.
Silver mineralization at Santo Domingo is part of a regional system located along the rift faults and there has been historical commercial production at Cinco Minas (~39 million ounces) and at San Pedro de Analco (~12 million ounces). Production at Santo Domingo was carried out as a satellite operation to San Pedro.
Veined mineralization which was historically mined, occurs in rift faults and splays primarily where the faults transect Sierra Madre volcanic rocks. The disseminated silver mineralization is hosted in conglomerates/lahars that unconformably overlie the Sierra Madre Volcanics. This as the mineralizing fluids rising up through the fault system dispersed laterally through the porosity of the conglomerates/lahars where cut by the rift faults. Alteration associated with the mineralization is characterized by disseminated fine grained pyrite, silicification together with quartz veining, and carbonate mineralization. Kaolin, sericite and propylitic alteration also occurs in trace amounts. Primary mineralization consists of: pyrite, galena, sphalerite, chalcopyrite, arsenopyrite, acanthite and jalpaite. Supergene mineralization consists of: chalcocite, hemimorphite chrysocolla, angelsite, cerussite, magnetite, hematite and goethite.
Stew Fumerton is a geologist who for the past forty years has worked in exploration, basic mapping and research primarily here in Canada but also in Africa, Asia, Europe and Latin America. The work at Santo Domingo was part of a program to upgrade the definition of drilling and the geological setting of the mineralization.
The Calgary Mineral Exploration Group Society offers monthly lunchtime seminars relating to geology and mining in the province of Alberta, across Canada and around the world.
|MEG Calgary Monthly Luncheons – held the first Thursday every month|
|LOCATION||Ramada Hotel Downtown
708 – 8th Avenue SW
|TIME||Doors Open at 11:30AM
Talks Commence at 12:00PM
Please confirm your intention to attend by email to vtrapnell@MEGCalgary.com so that the appropriate number of sandwiches can be ordered.
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