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

FOLGUERA, A.; BOTTESI, G.; DUDDY, I.; MARTÍN-GONZÁLEZ, F.; ORTS, D.; SAGRIPANTI, L.; ROJAS VERA, E.; RAMOS V.A.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015

0895-9811

Apatite fission-track analysis performed on eighteen Mesozoic sediment samples of the Neuqu?en Basinfrom the Southern Central Andes orogenic front between 35?300 and 37?S has revealed Campanian- Paleocene (75-55 Ma), late Eocene-early Oligocene (35-30 Ma) and middle Miocene (15-10 Ma) cool- ing episodes. Each cooling episode corresponds closely with major unconformities observed in the preserved sedimentary sequences, and is associated with kilometer-scale additional burial and subse- quent 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 mag- matism 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.