K-Ar Age of Agua de la Piedra Volcanic Complex at Puesto Suárez, Río Negro

The Agua de la Piedra Volcanic Complex (APVC) has been defined as an integral part of the Quinelaf Superunit, which includes younger bimodal sequences than the so-called basaltic plateau of Somun Cura. The plateau and post-plateau effusions correspond to the major episodes of the Somun Cura Magmatic Province of (SCMP). The APVC emerges in the western periphery of the plateau and is composed of an association of lavas and pyroclastites from basaltic to trachytic. The core of the range on which the sequence crops out is mainly mesosilicic and the basic flows of radially disposed. At the eastern end of the trachyte site a dome-shaped body with at least two trachytic varieties is recognized. The K-Ar age of the grainy variety allows corroborating the presence of more than one effusive event within the Quinelaf Superunit and establishing some criteria to discuss its relationship with the basaltic plateau. © 2018 Museo Argentino de Ciencias Naturales Bernardino Rivadavia.