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Jurassic raft tectonics in the northeastern Gulf of Mexico

Robin S. Pilcher, Ryan T. Murphy and Jessica McDonough Ciosek
Jurassic raft tectonics in the northeastern Gulf of Mexico (in Salt tectonics and interpretation, Mark G. Rowan (prefacer), Thomas E. Hearon (prefacer), Francis J. Peel (prefacer), Simon A. Stewart (prefacer), Oriol Ferrer (prefacer), J. Carl Fiduk (prefacer), Steve Holdaway (prefacer), Webster U. Mohriak (prefacer), Van Mount (prefacer), David G. Quirk (prefacer) and Tim Seeley (prefacer))
Interpretation (Tulsa) (November 2014) 2 (4): SM39-SM55


The northeastern Gulf of Mexico is dominated by the 900-1800-m Florida Escarpment, which forms the bathymetric expression of the Cretaceous carbonate shelf edge. Outboard of the escarpment lies a region of salt-detached raft blocks, which are closely analogous to type examples in the Kwanza Basin, Angola, in terms of structural style, scale, and amount of extension. We undertook the first detailed structural interpretation of an emerging petroleum exploration province. The rafts detached and translated basinward by gravity gliding on the autochthonous Louann salt in the late Jurassic to early Cretaceous. The Upper Jurassic source rock (lime mudstones) of the Smackover Formation and eolian sandstone reservoir intervals of the Norphlet Formation are structurally segmented and entirely contained within the raft blocks. The rafts are separated by salt ridges and/or extensional fault gaps containing expanded uppermost Jurassic and lower Cretaceous strata of the Cotton Valley Group. The main episode of rafting occurred after deposition of the Smackover and Haynesville Formations and broke the Jurassic carbonate platform into raft blocks 2-40 km in length, which were then translated 25-40 km basinward from their original position. Map-view restoration of the raft blocks suggested a minimum extension of 100%, with basinward transport directions indicating a radial divergence of rafts. In the north of the study area, the transport direction was westerly, whereas in the south, translation was southerly. This pattern, which mimics the Florida Escarpment, suggested that the morphology of the Jurassic slope controlled the style of gravitational tectonics and the location of subsequent Cretaceous carbonate buildups. As with other linked systems on mobile substrates, the observed extension and translation must be balanced by downdip contraction. In the case of the northeastern Gulf of Mexico, the contraction is largely cryptic, being accommodated by salt evacuation, compression of salt walls/stocks, and possibly open-toed canopy advance.

ISSN: 2324-8858
EISSN: 2324-8866
Serial Title: Interpretation (Tulsa)
Serial Volume: 2
Serial Issue: 4
Title: Jurassic raft tectonics in the northeastern Gulf of Mexico
Title: Salt tectonics and interpretation
Author(s): Pilcher, Robin S.Murphy, Ryan T.McDonough Ciosek, Jessica
Author(s): Rowan, Mark G.prefacer
Author(s): Hearon, Thomas E., IVprefacer
Author(s): Peel, Francis J.prefacer
Author(s): Stewart, Simon A.prefacer
Author(s): Ferrer, Oriolprefacer
Author(s): Fiduk, J. Carlprefacer
Author(s): Holdaway, Steveprefacer
Author(s): Mohriak, Webster U.prefacer
Author(s): Mount, Vanprefacer
Author(s): Quirk, David G.prefacer
Author(s): Seeley, Timprefacer
Affiliation: Hess Corporation, Houston, TX, United States
Affiliation: Rowan Consulting, Boulder, CO, United States
Pages: SM39-SM55
Published: 20141101
Text Language: English
Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States
References: 68
Accession Number: 2015-007655
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: chart, sects., sketch maps
N28°00'00" - N30°00'00", W90°30'00" - W87°00'00"
Secondary Affiliation: ConocoPhillips, USA, United StatesNational Oceanography Centre, GBR, United KingdomSaudi Aramco, SAU, Saudi ArabiaRoyal Holloway University of London, GBR, United KingdomSchlumberger, USA, United StatesChevron, USA, United StatesUniversidade do Estado do Rio de Janeiro, BRA, BrazilAnadarko, USA, United StatesMaersk, DNK, DenmarkHess, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by Society of Exploration Geophysicists, Tulsa, OK, United States
Update Code: 201504
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