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

FOLGUERA ANDRES; BOTTESI GERMAN; DUDDY IAN; MARTIN GONZALEZ FIDEL

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 1 p. 1 - 20

0895-9811

Apatite fission-track analysis performed on eighteen Mesozoic sediment samples of the Neuquen Basinfrom the Southern Central Andes orogenic front between 35300 and 37S has revealed Campanian-Paleocene (75-55 Ma), late Eocene-early Oligocene (35-30 Ma) and middle Miocene (15-10 Ma) coolingepisodes. Each cooling episode corresponds closely with major unconformities observed in thepreserved sedimentary sequences, and is associated with kilometer-scale additional burial and subsequentexhumation. A similar degree of cooling is inferred from associated vitrinite reflectance data. LateEocene-early Oligocene exhumation is recognized only near the eastern orogenic front adjacent to theforeland in the southernmost part of the study area and may be related partly to within-plate magmatismand associated extension in the Palaoco Basin. The Campanian-Paleocene and middle Miocenecooling episodes are recognized more widely in the fold and thrust belt and appear to coincide withperiods of eastward arc expansion and mountain building processes.