%0 Journal Article
%T La Formaci車n Garamilla: evento volc芍nico del Jur芍sico Inferior del sector occidental de la Comarca Nordpatag車nica, Provincia de R赤o Negro, Argentina
%A Benedini
%A Leonardo
%A Gregori
%A Daniel
%J Serie Correlaci車n Geol車gica
%D 2011
%I Instituto Superior de Correlaci車n Geol車gica
%X The Garamilla Formation: Lower Jurassic volcanic event in western Comarca Nordpatag車nica, R赤o Negro province, Argentina. The Garamilla Formation cropping out at the western edge of the NordpatagonianRegion is composed by volcanic and pyroclastic rocks of andesites, dac赤ticas and rhyolitic compositions whose age extends from the Late Triassic to Early Jurassic. In the area of the puestos Qui enao, Fuensalida and ca adones Mencu谷, Blancura and Curr迆 Mahuida appears a sequence 800 m thick where three volcanic events were recognized.The first one consists of domes and rhyolitic lavas, as well as lava-like ignimbrites. The second is represented by dikes and andesitic to dacitic lava flows, lapilli-tuffs and eutaxitic lapilli-tuffs of dacitic composition. The third event is made up of tuffs, rheomorfic tuffs, lapilli-tuffs, volcanic breccias, lava flows and dikes. This unit forms a calc-alkaline series related to a subduction process. An U-Pb age of 185 ㊣ 2 Ma (Pliesbachian) was obtained for the lapilli-tuffs lithofacies of the second volcanic event. These features allow correlation with the Lower Jurassic calcalkaline volcanism developed in the Neuqu谷n province.
%K Garamilla Formation
%K Nordpatagonian Region
%K Jurassic magmatism
%K Argentina.
%U http://www.insugeo.org.ar/libros/cg_28-1/10.htm