followed by the Perez formation during the Pliocene and Pleistocene. These formations were all affected by terrain uplift and folding, probably linked to changes in the subduction regime. Volcanism continued into the late Pleistocene and Holocene, and was accompanied by glacial activity during the Pleistocene. During this whole time period, volcanic activity progressively migrated westward; presently, it is located on the Bolivia-Chile border. Local Parinacota is a highly symmetric volcanic cone, having the classical "regular cone" shape of a stratovolcano. The volcano is high and features both blocky lava flows and scoria flows. Lava flows are fresh with levees, lobes and flow ridges, and reach lengths of on the slopes of the cone. The lava flows are between thick and can spread to widths of at the foot of the volcano. Pyroclastic flows are also found, reaching lengths of and are usually poorly consolidated, containing breadcrust bombs and breccia. The volcano is capped by a wide and deep summit crater, which has a pristine appearance. Other data imply a width of and a depth of . The crater is the source of pumice flows, which have well conserved surface features such as levees and lobes especially down on the eastern slope. These pumice flows extend as far as away from the crater. An ashfall deposit spreads east from Parinacota to a distance of in Bolivia. Ash and lapilli deposits have been found at the shores of Lake Chungará as well. The cone sits atop a thick multilobed andesitic platform known as the "Chungará Andesites" which crop out on the north shore of Lake Chungará in the form of a shelf. Overlying this shelf is a system of lava domes, which reach thicknesses of . The lava domes are accompanied by block and ash flow deposits that reach lengths of . A steep descent leads to Lake Chungará.South of the main edifice lie the parasitic vents known as the Ajata cones, which formed along a fissure that emanates from the main cone and is aligned with the regional Condoriri-Parinacota lineament. The dimensions of the cones reach width and height. The High Ajata flow emanates from a single cone and spreads southwest as a lobated lava flow. The middle Ajata flow is much smaller and is sourced to three different cones below the source of the High Ajata, each cone having its own small flow field. The upper and lower Ajata flows