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H. J. Belotti
L. L. Saccavino
G. A. Schachner
Perez Companc
Neuquén, Argentina
Abstract
The sub-Andean
fold and thrust belt of northern Argentina is characterized by a set of
north-northeast and south-southwest oriented structural trends. Major oil
and gas accumulations occur in the eastern sub-Andean ranges, including
the Ramos, Aguaragüe, Campo Duran, and Madrejones fields. Thin-skinned
deformation involves a tectonic wedge that generated triangle zones bounded
by a lower detachment in the Silurian Kirusillas Formation and by an upper
detachment at the base of the Upper Devonian Los Monos Formation. In the
Ramos and Aguaragüe structures, this configuration creates a distinct
disharmony between the tectonic wedge and its passive roof. The shortening
is accommodated by major tectonic thickening of the Los Monos Formation,
while the overlying Carboniferous and Tertiary units are deformed into
box folds. In the Aguaragüe structure, these overlying units are cut
by imbricate thrusts that offset the box fold crest eastward with respect
to the anticlinal axis of the underlying tectonic wedge. The Campo Duran
structure represents an early stage of this process without active folding
of its passive roof. In contrast, the Madrejones structure transferred
shortening to the foreland, forming the Ipaguazu structure. Balanced cross
sections were used in the interpretation of structural styles and hydrocarbon
traps to resolve the structures and reduce the exploration risk. |
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