Published 1995 as part of Memoir 62
Copyright © 1995 The American Association of Petroleum Geologists.    All Rights Reserved.

The Malargüe fold and thrust belt formed by Mesozoic rift inversion during Tertiary compressional orogeny. Mesozoic extension created the Neuquén basin in west-central Argentina and controlled most structural styles and the geometry of the fold and thrust belt, which is characterized by basement-cored oppositely verging structures. Subsidence curves and palinspastically restored isopach maps of Mesozoic sedimentary fill describe a complex pattern of asymmetric half-grabens bounded by major faults of opposite polarity and accommodation zones related to a rift phase during Late Triassic-Early Jurassic time, as well as Middle Jurassic-Early Cretaceous postrift regional subsidence. Balanced cross sections show the relationship between preexisting extensional fabrics and contractional basement-involved thrusts and back-thrust structures that generated the half-graben inversion. Overpressured shales and three evaporite levels favored formation of duplexes, triangle zones, and detachment of the cover as a result of basement-involved shortening.