| Summary: | The Perdido fold belt is the compressional toe of the complex system of detached
structures in the western Gulf of Mexico. Located in the Alaminos Canyon protraction
area in ultra deep-water, this extensive fold belt has the potential to accommodate large
amounts of hydrocarbons. These folds detach upon Jurassic-age Louann salt, and are
northeast-southwest trending and symmetrical to asymmetrical. The lower units in these
folds are comprised of mostly carbonates and limy carbonate mud, whereas the upper
portion consist of fine grained and muddy siliciclastics which are typical of turbidite and
other typical deep water deposits. 2-D, prestacked, depth-migrated seismic data (TGS
Phase 45) was interpreted in conjunction with Hess Corporation to determine the
geometry and timing of the folds outboard of the allochthonous Sigsbee salt nappe. The
interpretation of the seismic data consisted of evaluating the folds by mapping age-dated
reflections and kink-band boundaries (fold axial surfaces), along with creating isochores
and dip maps. Through the development of new geometric model building of excess
areas, which identifies material being added to the cores of the anticlines, along with the
extensive seismic interpretation, the Perdido fold belt is identified to have originated in
the west as early as the early Paleocene, with some continual fold growth to near present day. The folds in the Perdido fold belt continue to form eastward into the basin, up to
the basinward limit of the autochthonous Louann salt. Also, it has been determined that
the geometries and structural styles of the folds are partially dependent on the type of
sediment or rock type in place. The lower portions consisting of the carbonates give
shallower dipping fold axial surfaces, whereas the upper portions (siliciclastics) provide
more steeply dipping fold axial surfaces.
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