Love, Frank R.1
(1) Shell Deepwater, Houston, TX
ABSTRACT: Fold Belt Development Espirito Santo Basin, Brazil
Near the Espirito Santo Basin margin a fold-belt developed along strike from shortened salt diapirs, incipient salt canopies, to mature salt napes, which override compressional folds. Furthermore, although the fold-belt shows linkage to updip extension and sedimentary loading, there is evidence that basement transpression may have influenced this system.
The Espirito Santo Basin is the northern continuation of the Campos Basin petroleum system. The two basins are offset by a major transform, which is evident on gravity data, and by a step in the outer edge of a series of salt napes that override a basin bounding basement horst. Along the next inboard horst block set there is a set of compressional features similar to the Perdido Fold Belt. The fold-belt along ANP block BM-ES-10 begins as a shortened salt diapir then collapses and welds into an incipient salt canopy. As this fold belt steps across a sub-regional transform the system becomes salt deficient and forms a back thrusted fold. The next fold train inboard, is then overridden by a salt nape created by up dip sedimentary loading.
Outboard of these features is a large salt withdrawal basin which has welded and may have re-coupled the overlying sediments to basement structures which undergo transpression in the Eocene. The sub-regional transform, which offsets the incipient salt canopy from the salt nape, is leaky and Eocene volcanics have intruded the fold belt concominent with sedimentary fill of the adjacent fold limbs
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.