Geología de una pegmatita de tipo albita: la mina Independencia Argentina

GALLISKI M. A., MÁRQUEZ-ZAVALÍA M. F. OYARZÁBAL J. C. Y CORTONA O.

Revista de la Asociación Geológica Argentina

Instituto Salesiano de Artes Gráficas

Lugar: Buenos Aires; Año: 1994 vol. 49 p. 306 - 312

0004-4822

ABSTRACT. The geology oían albite type pegmatite: the Independencia Argentina mine. The Independencia Argentina mineis an albite type, rare element clase pegmatite, located in the San Luis range at 65°55'28"W and 32°54'20"S. The pegmatite cropsout in the SE border of a pegmatite population linked with the small stock of Cerro La Torre. This intrusive is a fertil granitein rare element pegmatites of LCT signature of probably Ordovician age, that intrudes micaceous schists of medium grade. Thepegmatite has N35°-40°E strike and 45°-70°W clip, it is tabular, with 200 m long and 5 m wide average size in the main segment,but in the central part it reaches 30 m wide. The internal zonation is asymmetric, the wall and intermediate zones are in thewest portion and they are principally composed by albite and quartz • muscovite; acaree K-feldspar and spodumene are partiallyreplaced. The quartz core is in the E side, and has poda of muscovite or albite in the transition to the inner intermediate zone.A tabular replacement unit of saccharoidal albite that reaches 3 m wide in some parta is located in the hanging wall portion.The accesory minerals are tantalite, columbite, microlite?, bismuth?, apatite, beril, garnet and hematite. The albite is presentas clevelandite in the dillerent units or sacchamidal albite in the replacement unit. The saccharoidal albite has An.compositionand a high grade of Al:Si order. The pegmatite was emplaced early sinkynematically during the Ocloyic diastrophism and taterwas boudinaged especially in the southern part. lis moat probable origin is by sinkynematic fracciona] cristallization of one ofthe latest batches of pegmatitic magma derived from the Cerro La Torre granite differentiation.