Geology of the late Pliocene - Pleistocene Acoculco caldera complex, eastern Trans-Mexican Volcanic Belt (Mexico)

We present a new 1:80,000-scale geologic map of the Acoculco caldera (Ac) located between the states of Puebla and Hidalgo in eastern Mexico. The map, encompassing an area of 856 km(2), is grounded on an ArcMap data set and is supported by nine new 40Ar/39Ar dates. The caldera lies upon Cretaceous limestones and Miocene to Pliocene volcanic rocks (13-3 Ma). The caldera consists of 31 lithostatrigraphic units formed between 2.7 and 0.06 Ma that include a wide variety of volcanic landforms (cinder cones, lava domes). The caldera has a semi-circular shape (18-16 km) bounded by the Atotonilco scarp to the north, the NW-SE Manzanito fault to the west, and scattered vents to the east and southern parts. The distribution of the Acoculco ignimbrite, the lithic breccia, and lacustrine sediments define the caldera ring fault. Late Pleistocene activity and pervasive hydrothermal alteration suggest a high geothermal potential in the area.