The massif is part of the 5200 km2 Payún Matru volcanic field. On top of SW flank of the caldera, the Cerro Payún stratovolcano was constructed nd formes the highest point.
The Pleistocene Pampas Onduladas pahoehoe lava flow traveled 181 km, Earth's longest known Quaternary lava flow.
Post-caldera basaltic eruptions produced more than 300 eruptive centers, mostly along E-W-trending fissures that extend across the entire shield volcano. Fluid aa lava flows from young vents on the west flank known as Los Volcanes traveled more than 10 km. Other vent clusters of are found on the lower NE and southern flanks, and a lava flow from Volcán Santa María on the NW flank traveled 15 km to the NE.
At least 30 trachyandesitic lava domes and basaltic lava flows were erupted contemporaneously with the basaltic fissure eruptions.
Oral traditions note that native tribes were present at the time of the latest eruption.
Source: GVP Payún Matru volcano information