BEAVERITA, PLUMBOJAROSITA Y OTROS MINERALES SECUNDARIOS DE Pb-Cu-Zn DE LA ZONA DE OXIDACIÓN DE LA MINA MARÍA DEL VALLE, DISTRITO LAS AGUADAS, SAN LUIS

COLOMBO, FERNANDO; LIRA, RAÚL; PANNUNZIO MINER, ELISA VICTORIA

Río Cuarto

Congreso; 7º Congreso de Mineralogía y Metalogenia; 2004

Departamento de Ciencias Geológicas (UBA) y Departamento de Geología (Univ. Nac. de Río Cuarto)

María del Valle mine is a hydrothermal vein deposit located some 15 km East of Quines (San Luis Province, Argentina). A suite of secondary Pb-Cu-Zn species was found in the oxidation zone. Beaverite occurs intermixed with plumbojarosite as microcrystalline masses up to 1 cm thick encrusting quartz and galena altered to cerussite. They are greenish yellow to brownish yellow and have silky to earthy luster. EDS analyses show Pb and Fe (S is masked by the PbMa line), with very minor Cu, K, Na, Al and Si. No As or P were detected. Cell dimensions are: (beaverite) a = 7.2446(9) Å, c = 17.109(2) Å, V = 777.6(2); (plumbojarosite) a = 7.3068(5) Å, c = 33.566(3)Å, V = 1552.0(2) Å3. These alunite-group minerals formed due to the attack of galena by low temperature acid solutions. Other species found at María del Valle mine include mottramite crusts (no Zn detectable by EDS), hemimorphite crystals to 0.8 mm showing forms {010}, {110}, {301} and {031}, goethite intimately intermixed with plumbojarosite, malachite, azurite, abundant massive and crystallized cerussite, gypsum and celestite.