Pomerape is a complex of lava domes, accompanied by lava flows which were emplaced atop of the domes. It was active about 200,000 years ago. The lava domes formed first and were later buried by the actual volcanic cone, which unlike the rhyolitic-dacitic domes is formed by hornblende andesite. The "Chungará Andesites" and lava dome complex of Parinacota were laid down at this time. Pomerape is associated with an adventive vent that has erupted mafic magmas. The main cone was last active 106,000 +- 7,000 years ago, the adventive vent is dated to 205,000 ± 24,000 years ago.
Climbing the volcano is alpine grade PD by the east ridge. Harder routes exist on the south face, sometimes on 50+ degree snow/rubble slope. For these routes a camp can be established at 5,300 metres (17,390 ft) at the saddle between Parinacota and Pomerape. Depending on the season, the main difficulty can be penitentes (tall ice-blade needles), which make the ascent physically difficult or impossible.
^Schull, William J. (1990). "Introduction: The Place and the Study". In Schull, William J.; Rothhammer, Francisco (eds.). The Aymara. Studies in Human Biology. 2. Springer Netherlands. pp. 1-18. doi:10.1007/978-94-009-2141-2_1. ISBN9789401074636.
^Gonzalez-Ferran, Oscar (1994). Volcanes de Chile (in Spanish) (1st ed.). Santiago, Chile: Instituto geografico militar. p. 113. ISBN9789562020541.
^Wörner, Gerhard; Moorbath, Stephen; Horn, Susanne; Entenmann, Jürgen; Harmon, Russel S.; Davidson, Jon P.; Lopez-Escobar, Leopoldo (1994). Reutter, Professor Dr Klaus-Joachim; Scheuber, Dr Ekkehard; Wigger, Dr Peter J. (eds.). Tectonics of the Southern Central Andes. Springer Berlin Heidelberg. p. 81. doi:10.1007/978-3-642-77353-2_5. ISBN9783642773556.
^Hora, J. M.; Singer, B. S.; Worner, G. (2007). "Volcano evolution and eruptive flux on the thick crust of the Andean Central Volcanic Zone: 40Ar/39Ar constraints from Volcan Parinacota, Chile". Geological Society of America Bulletin. 119 (3-4): 343-362. Bibcode:2007GSAB..119..343H. doi:10.1130/b25954.1.