Structural Style of the Cuyo-Bolsones Basin Complex of West-Central Argentina

GOLLOP, IAN G., Eurocan Ventures Limited, Vancouver, British Columbia, Canada

The Cuyo-Bolsones basin complex is part of a mosaic of basinal features that lie in the eastern Andean foreland. Sedimentary section ranges from Ordovician to Tertiary in age with the main petroleum source and reservoir potential in Carboniferous to Triassic clastics.

Thick conglomerate units and widespread unconformities of both Permo-Carboniferous and Triassic age as well as localized volcanics indicate several periods of violent tectonic activity during late Paleozoic to early Mesozoic times.

Triassic and older sediments are affected by normal faulting which in basins directly south extends up into the Lower Cretaceous. In the Cuyo-Bolsones basinal area however, this ancient tensional regime is entirely overprinted by relatively recent thrusting. This thrusting is late Tertiary in age, generally from east to west with very substantial relief These thrust sheets are cut in places by later northeast-southwest strike-slip fault zones producing some localized flower structures. Nearly all the oil discovered in the Cuyo basin is produced from Triassic clastic reservoirs in compressional anticlines related to this thrusting.

The major thrusts are well defined seismically, and seismic interpretations fit easily on balanced sections.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)