IGNIMBRITE STRATIGRAPHY OF THE “VOLCANIC” WESTERN CORDILLERA AND ADJACENT ALTIPLANO IN THE REGION OF THE PUCHULDIZA GEOTHERMAL AREA (19°15'S TO 19°25'S), NORTHERN CHILE: IMPLICATIONS FOR ALTIPLANO UPLIFT
(1) Late Oligocene (25 Ma) rhyolite ignimbrites, previously mapped as Cretaceous; these are equivalent to the “strongly-folded Belén ignimbrites”  at 17°20’S.
(2) Early Miocene rhyolite ignimbrites, including 18.8±0.4 Ma Utayane Formation and 18.9±0.7 Ma Condoriri Formation. These are age-correlative with the Oxaya ignimbrites, which extend 300 km N-S from Peru to Chile, and 130 km E-W from the Altiplano to the coast . This age cluster also includes previously unrecognized, distinctive pyroxene trachydacite/dacite ignimbrites (18.3±0.3 Ma), interstratified with lavas of the same composition previously referred to as “andesites” of Lower Puchuldiza Formation.
(3) Middle Miocene (14.6±0.4 Ma to 13.0±0.3 Ma) rhyolite ignimbrites, including “Upper Puchuldiza Formation”, and previously unrecognized rhyolite ignimbrites: a composite ignimbrite sheet overlain in angular unconformity by a distinctive lava-like ignimbrite, also folded.
(4) Flat-lying Pliocene dacite ignimbrite (3.02±0.15 Ma), similar to the 2.7 Ma “post-tectonic” Lauca-Perez ignimbrite , which covers wide areas to the north in Chile, Peru & Bolivia, and reaches the coast.
Our chronostratigraphy reveals an episode of wide-spread east-vergent thrusting, whose contemporaneity with the onset of Altiplano uplift places important constraints on existing geodynamic models.
 Schröder W., Wörner G., 1996. Symp. Int. Géodynam. Andine, Saint-Malo (FRA), 645-648.  Wörner et al., 2002, Tectonophysics 345:183-198.