INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
Se-bearing polybasite-Tac from the Martha mine, Macizo del Deseado, Santa Cruz, Argentina
MÁRQUEZ-ZAVALÍA, M.F.; BINDI, L.; MÁRQUEZ, M.; MENCHETTI, S
MINERALOGY AND PETROLOGY
Lugar: Viena, Austria; Año: 2007
Abstract Se-bearing polybasite-Tac is associated with galena, chalcopyrite, sphalerite, tetrahedrite, electrum and quartz at the Martha mine, an epithermal silvergold deposit located adjacent to the Deseado Massif, Santa Cruz province, Argentina. Three samples, with variable chemical composition and showing the 111 unit-cell type, were studied by means of X-ray single crystal diffraction and electron microprobe. The unit-cell parameters were modeled using a multiple regression method as a function of the Ag, Sb, and Se contents. The predicted values resulted in excellent agreement with experimental unit-cell parameters. We observed that high contents of selenium in polybasite are associated with relatively low copper contents. This finding corroborates previous studies that the copper content of pearceitepolybasite group minerals can be very low if selenium is present.