Geologic and tectonic setting of Deseado Massif epithermal deposits, Argentina, based on El Dorado-Monserrat

Porphyry, epithermal, and orogenic gold prospectivity of Argentina

“…Bimodal volcanism during the middle to late Jurassic resulted in the deposition of the intermediate Bajo Pobre Formation (basalt-andesitic rocks) followed by the more acidic Bahía Laura Group (ignimbrites and tuffs) (Fernández and de Barrio, 1994). Overlying the Jurassic volcanic sequences are Cretaceous and Cenozoic basalts and marine sedimentary rocks (Schalamuk et al, 1997;Echavarría et al, 2005). Extensional tectonism during the Jurassic led to the formation of large, NNW-to N-trending half-grabens, bounded by steeply listric normal faults, most of which were reactivated structures of the former Permo-Triassic rift (Gust et al, 1985;Uliana et al, 1989;Homove and Constantini, 2001).…”

“…The mineralization is largely hosted in the Bahía Laura Group, which consists of the dominantly ignimbritic sequence, referred to as Chon Aike Complex by Pankhurst et al (1993aPankhurst et al ( , 1993b, whereas the interbedded dominantly tuffaceous sequence is referred to as La Matilda (Panza and Nullo, 1994;Echavarría et al, 2005;Fernández et al, 2008). Geochronology confirms the genetic relationship between the Jurassic volcanism and the epithermal mineralization, with the hydrothermal systems being established during the late stages of volcanic activity (Echavarría et al, 2005).…”

“…The mineralization is largely hosted in the Bahía Laura Group, which consists of the dominantly ignimbritic sequence, referred to as Chon Aike Complex by Pankhurst et al (1993aPankhurst et al ( , 1993b, whereas the interbedded dominantly tuffaceous sequence is referred to as La Matilda (Panza and Nullo, 1994;Echavarría et al, 2005;Fernández et al, 2008). Geochronology confirms the genetic relationship between the Jurassic volcanism and the epithermal mineralization, with the hydrothermal systems being established during the late stages of volcanic activity (Echavarría et al, 2005). The most volumetrically widespread hydrothermal alteration process is silicification, although argillization, sericitization, and propylitization are also observed; the alteration extents typically from a few meters to a few tens of meters adjacent to quartz veins (Schalamuk et al, 1997).…”

Geology of the Manantial Espejo epithermal district, Deseado Massif, Patagonia Argentina

“…This public and private exploration identified new targets with mining potential (Fernández et al, 2008 and references cited there), while academic research (Echavarría, Schalamuk, & Etcheverry, 2005;Echeveste, 2005a;Guido, 2002;Jovic, 2010;López, 2006;Moreira, 2005;Mykietiuk, 2006;Páez, 2012;Permuy Vidal, 2014;Ruiz, 2012;Wallier, 2009) provided data on the mineralization type -epithermal low to intermediate sulfidation -as well as its spatial and genetic association with the Jurassic volcanism.…”

A new Middle–Late Jurassic flora and hot spring chert deposit from the Deseado Massif, Santa Cruz province, Argentina

“…Geothermal activity accompanied volcanism in the region, and recent mineral exploration activity in the Deseado Massif has revealed the presence of numerous epithermal systems and terrestrial hot spring sinter and travertine deposits (e.g. Schalamuk et al 1997;Echavarría, Schalamuk & Etcheverry, 2005).…”