Exhumation of the Neuquen Basin in the southern Central Andes (Malargile fold and thrust belt) from field data and low-temperature thermochronology

Apatite fission-track analysis performed on eighteen Mesozoic sediment samples of the Neuquen Basin from the Southern Central Andes orogenic front between 35 degrees 30' and 37 degrees S has revealed Campanian-Paleocene (75-55 Ma), late Eocene-early Oligocene (35-30 Ma) and middle Miocene (15-10 Ma) cooling episodes. Each cooling episode corresponds closely with major unconformities observed in the preserved sedimentary sequences, and is associated with kilometer-scale additional burial and subsequent exhumation. A similar degree of cooling is inferred from associated vitrinite reflectance data. Late Eocene-early Oligocene exhumation is recognized only near the eastern orogenic front adjacent to the foreland in the southernmost part of the study area and may be related partly to within-plate magmatism and associated extension in the Palaoco Basin. The Campanian-Paleocene and middle Miocene cooling episodes are recognized more widely in the fold and thrust belt and appear to coincide with periods of eastward arc expansion and mountain building processes. (C) 2015 Elsevier Ltd. All rights reserved.