Geology and exploratory potential of the Cerro Cuadrado and El Bagual polymetallic epithermal manifestations (Santa Cruz, Argentina)

Abstract

The geology and exploratory potential of the polymetallic (Ag-Zn rich) epithermal manifestations of Cerro Cuadrado and El Bagual, located in the northwestern corner of the Santa Cruz province, in southern Patagonia, are described. Both manifestations are temporal and spatially associated with the emplacement of a dome and pyroclastic eruptive felsic units of the El Quemado Formation, related to the Jurassic plateau of the Deseado Massif. The main mineralization at Cerro Cuadrado and El Bagual occurs in veins, veinlets and brecciated areas along N-S trending fault corridors associated with apical portions and in the peripheries of domic structures with several hundred meters in diameter. In the Cerro Cuadrado, the mineralization is preferentially arranged in narrow vein corridors and banded areas rich in Ag and Zn that increase their thickness in dilating jogs of faults in the central portions of the dome. In the El Bagual, gold-silver veins and the presence of a subvertical cylindrical late intrusive body of a few dozen meters in diameter, called the Central Chimney, this structure represents a diatreme filled with volcanic agglomerates with metamorphic subangular lithic fragments of the underlying the Late Paleozoic Rio Lácteo Formation. Both polymetallic manifestations present a very interesting exploratory potential related to the outer areas of a Jurassic rhyolitic dome-complex model.