Pearceita asociada a Paragénesis de Oro y Plata en la Veta Viscaya, Distrito Minero Zaruma-Portovelo, República del Ecuador

MUTTI, D.; MÉNDEZ, C.; DI MARCO, A.; BONILLA, W.

San Miguel de Tucumán

Congreso; XII Congreso de Mineralogía y Metalogenia; 2016

asociación Mineralógica Argentina

ResumenSe identificó la sulfosal de plata pearceita, hallada por primera vez en el distrito minero Zaruma-Portovelo, República del Ecuador. Este mineral hospedado en la veta Viscaya del sistema estructural Viscaya ? Nicole, se encuentra vinculado con una paragénesis de pirita, calcopirita, esfalerita, galena, tetraedrita, petzita, oro nativo y electrum en ganga mayoritaria de cuarzo. La pearceita, identificada mediante microscopía de reflexión y analizada con un microscopio electrónico de barrido, posee la fórmula estructural (Ag13.55, Cu3.71)∑17.26 (As1.11, Sb0.73)∑1.84 S11.55., mientras que la tetraedrita presenta una composición de (Cu8.49, Fe1.91, Ag1.46)∑11.86 (Sb2.85, As0.84)∑3.69 S12.78. A partir de las relaciones de contacto de la pearceita con la tetraedrita, sus texturas y sus composiciones, se interpreta que ambas sulfosales fueron coevales y que el Sb y As del fluido hidrotermal se particionaron diferencialmente entre ambas. AbstractPearceite, a sulfosalt of arsenic and silver, was identified and discovered for the first time in the Zaruma- Portovelo mining district, Republic of Ecuador. This mineral hosted by the Vizcaya vein from the Vizcaya ? Nicole structural system is linked to a paragenesis of pyrite, chalcopyrite, sphalerite, galena, tetrahedrite, petzite, native gold and electrum into a majority gangue of quartz. The pearceite identified by reflection microscopy and analized with a scanning electronic microscopy, present the structural formula (Ag13.55, Cu3.71)∑17.26 (As1.11, Sb0.73)∑1.84 S11.55., while tetrahedrite has a composition of (Cu8.49, Fe1.91, Ag1.46)∑11.86 (Sb2.85, As0.84)∑3.69 S12.78. Since contact relations between pearceite and tetrahedrite, theirs textures and compositions, is interpreted that both sulphosalts were coeval, and the Sb and As of the hydrothermal fluid partitioned differentially between the two mineral series.