Parinacota Volcano in the context of Cordillera Occidental (Bolivia)

The Cordillera Occidental or Western Cordillera of Bolivia is part of the Andes (that is also part of the American Cordillera), a mountain range characterized by volcanic activity, making up the natural border with Chile and starting in the north with Juqhuri and ending in the south at the Licancabur volcano, which is on the southern limit of Bolivia with Chile. The border goes through the innominated point located at two-thirds of elevation of Licancabur's northeastern slope at the southwesternmost point of Bolivia at 22° 49' 41" south and 67° 52' 35" west. The climate of the region is cold and inadequate for animal and plant life. Its main feature is its ground, in which are large quantities of metallic minerals including gold, silver, copper, and others. The range consists of three sections:

• The northern section, in which you can find the highest peaks in Bolivia, tallest of which is the volcano Sajama at 6,542 meters. Sajama is perennially covered in snow. It contains the volcanoes Pomerape and Parinacota (called Payachata collectively), the latter being a dormant volcano with a cone of snow similar to Mount Fuji in Japan.
• The central section, situated between Uyuni and Coipasa. Its most prominent summit is the Ollagüe (Ullawi) volcano on the border with Chile.
• The southern section, characterized by volcanic activity and by having sandstorms and fog, taking into account Licancabur, which is 5,920 meters high (but only two-thirds of the northeastern slope of the volcano belong to Bolivia up to 5415 meters). The lakes Laguna Colorada and Laguna Verde can be found on Licancabur, so named because of their respective colors.

Pomerape is a stratovolcano lying on the border of northern Chile and Bolivia (Oruro Department, Sajama Province, Curahuara de Carangas Municipality). It is part of the Payachata complex of volcanoes, together with Parinacota Volcano to the south. The name "Payachata" means "twins" and refers to their appearance. It hosts glaciers down to elevations of 5,300–5,800 metres (17,400–19,000 ft), lower on the northern slope.

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.

Payachata or Paya Chata (Aymara pä, paya two, Pukina chata mountain, "two mountains") is a north–south trending complex of potentially active volcanos on the border of Bolivia and Chile, directly north of Chungará Lake. The complex contains two peaks, Pomerape to the north and Parinacota to the south. On the Bolivian side the volcanoes are located in the Oruro Department, Sajama Province, Curahuara de Carangas Municipality, and on the Chilean side they lie in the Arica y Parinacota Region, Parinacota Province.

According to helium surface dating, Parinacota has erupted within the last 2000 years, while Pomerape is Pleistocene.