Structural Evolution of the Thunder Horse Mini-Basin, Mississippi Canyon, Northern Deep Gulf of Mexico

Todd Lapinski, Renaud Bouroullec, and Paul Weimer
University of Colorado, Boulder, Colorado

Thunder Horse mini-basin in the southern Mississippi Canyon consists of several structural features that influenced its evolution. They are basement faults; one autochthonous and three allochthonous salt bodies of upper Albian, upper Cretaceous, and Neogene age; a growth fault and raft system; and a turtle structure associated with crestal faults. Remnant allochthonous salt pillows are present along the upper Albian horizon, whereas the upper Cretaceous salt has been completely welded out.

378 square miles of 3-dimensional seismic records, wireline logs, and biostratigraphy indicate that structural evolution can be divided into three intervals. From 99 to 66 Ma, the upper Albian allochthonous salt deformed and four remnant salt pillows developed. From 66 to 24 Ma, a northwest-trending trough formed to the south in association with withdrawal and migration of salt from an upper Cretaceous allochthon. A large salt pillow salt continued to deform northeasterly on the upper Albian allochthon. From 24 to 14.35 Ma, the trough of sediment continued to grow due to subjacent salt withdrawal. At 14.35 Ma, the sediment trough [weld?] out and started to invert because of salt withdrawal from beneath the flanks of the thick sediments comprising Thunder Horse turtle. Growth continued on the turtle structure until about 9.0 Ma. Between 11.4 to 9.3 Ma, the northeastern growth fault was active and the allochthonous salt collapsed resulting in sediments rafting downdip. Finally, major extrusion of the Neogene allochthonous salt sheet occurred between 9.0 and 6. 0 Ma as recorded by stratal cutoffs against the salt. This salt sheet completely overlies the North Thunder Horse field, and partially overlies the Thunder Horse field.

AAPG Search and Discovery Article #90032©2004 GCAGS 54th Annual Convention, San Antonio, Texas, October 10-12, 2004