ABSTRACT

The Cuyo-Bolsones basin complex is part of a mosaic of basinal features that lie in the eastern Andean Foreland. The sedimentary section ranges in age from Ordovician to Tertiary, and the main petroleum source and reservoir potential are 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 that extends up into the Lower Cretaceous in basins directly to the south. 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 trends east to west and has very substantial relief. These thrust sheets are cut in places by later northeast-southwest strike-slip fault zones that produce 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.

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