 Activity at Incapillo commenced shortly after the end of the Maricunga Belt volcanism and occurred first at Monte Pissis between 6 @.@ 5 and 3 @.@ 5 mya . Later volcanism occurred south of Incapillo 4 @.@ 7 ± 0 @.@ 5 mya , at Sierra de Veladero 5 @.@ 6 ± 1 – 3 @.@ 6 ± 0 @.@ 5 mya , and in the region of Cerro Bonete Chico 5 @.@ 2 ± 0 @.@ 6 – 3 @.@ 5 ± 0 @.@ 1 mya . Some of the 3 – 2 mya Pircas Negras mafic andesites appear to be associated with the Incapillo volcanic complex . These rocks form the last pulse of the Pircas Negras volcanism . Specific ages of the Pircas Negras flows in the Incapillo region include 4 @.@ 7 ± 0 @.@ 5 mya , 3 @.@ 2 ± 0 @.@ 3 mya and 1 @.@ 9 ± 0 @.@ 2 mya . Later , andesitic @-@ rhyolitic volcanism formed ignimbrites and lava domes 2 @.@ 9 ± 0 @.@ 4 – 1 @.@ 1 ± 0 @.@ 4 mya , with the youngest pre @-@ caldera dome being 0 @.@ 873 ± 0 @.@ 077 mya old . The lava domes formed through non @-@ explosive extrusion . 
