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	Cerro Purico ignimbrite centre
Synonyms: None
Location: 23º00'S; 67º04'W
Country: Bolivia
Average/Max Elevation: 4900m/5900m
Caldera Diam.: 3km x 3km
~Volume: ~1000 cub. km
Age Range: 1.3 to 0 Ma

The La Pacana Complex/Cerro Purico

The La Pacana Complex (LPC),is the largest of the caldera complexes in the APVC (Figure S7). It covers an area of ~17,000 km2 in N. Chile, SW Bolivia and NW Argentina, and consists of three major ignimbrite centres, which overlap temporally, spatially and structurally. Hot springs are found throughout the complex.

The youngest of the ignimbrite centres which make up the LPC is the Purico Complex (23º00'S; 67º4'W), located approximately 30 km east of San Pedro de Atacama on the northwestern margin of the La Pacana caldera. Its roughly radial symmetry and the low angle dips of the ignimbrite mantled flanks of the complex led Baker (1981) to describe it as an ignimbrite "shield". It seems likely, however, that these dips may reflect the pre-eruption topography and may therefore not be constructional phenomena associated solely with the ignimbrite centre. Two ignimbrite units are present. The older and more extensive is the1.3 Ma Lower Purico ignimbrite which forms the upper surface of the regional slope west of the centre. This ignimbrite now covers an area of ~800 km2 and is up to 100m thick. The Upper Purico ignimbrite occurs mainly on the summit regions of the complex (~4500 - 5000m) and to the east on the caldera wall and moat of the La Pacana caldera. A 0.8Ma old dacitic dome ('Dome D' of Francis et al., 1984) was the final phase of the upper Purico ignimbrite eruption and lies on the northern side of a 1 km diameter shallow depression which may mark the source vent of the ignimbrites.