Bolivia
Synonyms: None
Location: 20º51'S; 68º12'W
Type: Lava field
Aerial Extent: 2025 m
Number of Centers: >20
Located on the southwestern margin of the Salar de Uyuni in Bolivia is the little known Pampa Luxsar lava complex, an ~45 x 45km area of coalesced flows of different ages. However, although a large number of lava flows of variable character is discernible on TM images, there are few vents. Furthermore, no recent large composite volcanoes are found in this area, which is situated to the east of the modern volcanic front. Although of variable albedo, reflecting differences in age, the morphology of the lava flows is fairly uniform and consistent with andesitic to basaltic andesitic compositions. The lavas are distributed around remnants of large dissected cones, the largest of which is Cerro Luxsar (CL), a Pliocene to Pleistocene cone. Several young faults (i.e. F) can be seen seen cutting the older volcanoes and although their outcrop is largely obscured by the lavas, these faults may have controlled vent sites. It is likely that several phreatomagmatic eruptions occurred in this region as it was partly submerged during the last ice age; lake terraces are found at elevations up to 3,800 m which is the approximate base level of the lava field, and a large 2.5 km diameter maar-like vent Cerro Negro (CN) may be the result of this.
References
Davidson, J., and de Silva, S.L., 1995. Late Cenozoic magmatism of the Bolivian Altiplano. Contributions to Mineralogy and Petrology, 119(4): 387-408.
de Silva, S.L., Francis, P.W., 1991. Volcanoes of the Central Andes. Berlin: Springer-Verlag, 216 p.