EISNER, PABLO N., Maxus Energy Corporation, Dallas, TX, and ALBERT W. BALLY and PETER R. VAIL, Rice University, Houston, TX

ABSTRACT: Tectonic and Stratigraphic Evolution of Neuquen Basin, Argentina

Neuquen Basin is a mature basin with a long history of hydrocarbon production. It is the most productive subandean basin of Argentina. It was a Mesozoic backarc basin which evolved into a foredeep basin when a fold and thrust belt was formed to the west in the upper Cretaceous.

The sedimentary infill is Permo-Triassic to recent. It is continental and marine in origin and was deposited in a generally shallow, slowly subsiding basin. The main factors that help subdivide the stratigraphy of the basin were relative changes of sea level. Detailed sequence stratigraphic analysis of upper Jurassic to lower Cretaceous marine and continent clastics, carbonates and evaporites allowed to explain the mechanisms by which subtle stratigraphic traps may have been created.

The Neuquen Dorsal, a positive east-west structure in the relatively undeformed basin, has been tentatively interpreted as an inversion. This hypothesis must be further analyzed using additional data.

Deformation in the fold and thrust belt took place from the Campanian to Pliocene, and shows three distinct zones. From east to west a broad arch is followed by an intricate series of tight anticlines formed by both east and west verging thrusts which use four different decollement surfaces. To the west of these, a east verging ramp anticlinal structure is identified, which involves a deeper decollement surface.

AAPG Search and Discovery Article #90988©1993 AAPG/SVG International Congress and Exhibition, Caracas, Venezuela, March 14-17, 1993.