The Risco Plateado volcanic complex lies about 10 km S of the Caldera del Atuel and consists of a stratovolcano cut by a 4-km-wide caldera. Two eruptive centers are located on the SW and NE caldera rims along a NE-trending fracture that extends to a cone on the lower NE flank about 8 km from the caldera. Dominantly basaltic andesite lava flows overlie initial dacitic flows. Very youthful-looking basaltic lava flows from the NE-flank center extend NE to the Río del Atuel. Lava flows from the SW-rim center extend westward beyond the flanks of the complex and those from the NE-rim center flow into the caldera and down its NE flank.