THE VOLCANIC ASSOCIATION OF LAS LOMADAS AREA, CORONA CHICO VOLCANITES. SOMUN CURA MAGMATISM. RIO NEGRO PROVINCE, ARGENTINA

REMESAL, M B,; CERREDO M. E.; CORDENONS P. D; ALBITE, J:M:

Revista de Museo Argentino de Cienicas Naturales

Museo Argentino de Cienicas Naturales

Lugar: Buenos Aires; Año: 2019 vol. 21 p. 179 - 194

ABSTRACTThis contribution deals with the Corona Chico Vulcanites, within the Somún Curá Magmatic Province, northern Extra-andean Patagonia. The studied area is located to the north of the Alta Sierra de Somún Curá Magmatic Complex and is made of several basaltic volcanic buildings of varied morphologies: spatter cones, tuff ring and long lava flows related to small shield volcanoes (of scutulum type). Petrographic characteristics as well as whole rock chemical composition suggest a time progressive increase in alkalis content and a shift from early transitional terms to basanitic rocks in the latest stages. A simulation of the source yielded for Las Lomadas rocks an astenospheric source in the garnet-spinel facies, with associated low partial melting percentages (< 7-8%). Within the studied rock set, the spatter cones sequence displays geochemical affinities with the basaltic component of Alta Sierra de Somún Curá Volcanic Complex.