%0 Journal Article
%T La Formaci¨®n Garamilla: evento volc¨¢nico del Jur¨¢sico Inferior del sector occidental de la Comarca Nordpatag¨®nica, Provincia de R¨ªo Negro, Argentina
%A Benedini
%A Leonardo
%A Gregori
%A Daniel
%J Serie correlaci£¿3n geol£¿3gica
%D 2012
%I Scientific Electronic Library Online
%X the garamilla formation cropping out at the western edge of the nordpatagonian region is composed by volcanic and pyroclastic rocks of andesites, dac¨ªticas 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¨¦, blancura and curr¨² 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 ¡À 2 ma (pliesbachian) was obtained for the lapilli-tuffs lithofacies of the second volcanic event. these features allow correlation with the lower jurassic calc-alkaline volcanism developed in the neuqu¨¦n province.
%K garamilla formation
%K nordpatagonian region
%K jurassic magmatism
%K argentina.
%U http://www.scielo.org.ar/scielo.php?script=sci_abstract&pid=S1666-94792012000100010&lng=en&nrm=iso&tlng=en