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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 66 (1982)

Issue: 5. (May)

First Page: 554

Last Page: 554

Title: Pre-Cretaceous Geologic History of Deep Southeastern Gulf of Mexico: ABSTRACT

Author(s): Richard T. Buffler, Ronald L. Phair

Article Type: Meeting abstract

Abstract:

Analysis of seismic data and the results of DSDP Leg 77 reveal a complex pre-Cretaceous, pre-rift to post-rift geologic history for the deep southeastern Gulf of Mexico that is probably related to the early opening of the North Atlantic. The area is underlain by an extensive rifted and attenuated continental crust or transitional crust formed mainly in Late Triassic through Jurassic time owing to large-scale translational motions as the Yucatan-South American block pulled away from North America. Shallow holes drilled into the tops of tilted basement blocks encountered examples of this transitional crust (early Paleozoic metamorphic rocks intruded by Mesozoic diabase). The rifted basement is infilled and covered by an extensive syn-rift sequence of probable Jurassic age a d nonmarine origin (up to 2 km thick). Interpreted within this sequence is a narrow north-south-trending salt basin, which may be equivalent to the Louann salt in the northern Gulf basin and the salt in Cuba. Rifting mainly occurred during Late Triassic through Jurassic time, although in one broad area faulting and collapse of the basement apparently continued into the Early Cretaceous. The syn-rift sequence is overlain by a thick post-rift section of marine sedimentary rocks. DSDP Leg 77 drilled the upper part of the sequence and encountered a complete section of Lower Cretaceous deep-water carbonates. The lower part of the sequence lying below the deepest horizon drilled (Berriasian) has a similar character and is inferred to represent Upper Jurassic marine rocks, probably equivalent t the Late Jurassic (post-Louann) marine transgression observed around the periphery of the Gulf.

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