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The effects of base-salt relief on salt flow and suprasalt deformation patterns; Part 2, Application to the eastern Gulf of Mexico

Tim P. Dooley and Michael R. Hudec
The effects of base-salt relief on salt flow and suprasalt deformation patterns; Part 2, Application to the eastern Gulf of Mexico
Interpretation (Tulsa) (February 2017) 5 (1): SD25-SD38

Abstract

In the eastern Gulf of Mexico, the pattern of early stage salt flow is complicated by basement topography consisting of a series of plunging arches that trend obliquely to the early flow direction. Seismic lines downdip of the Florida Middle Ground Arch reveal a puzzling array of structures. Sections trending roughly north-south (parallel to the regional dip) document predominantly extensional structures; however, east-west sections reveal shortening structures. Both sets of structures occur well updip of the downdip salt pinchout. We designed a physical-modeling study to investigate these puzzling relationships. Models presented in Part 1 of this paper indicate that localized shortening and extension can occur as salt passes over simple base-salt steps. Physical models were run with complex salt isopachs featuring plunging arches oblique to dip and salt flow. Models reveal the formation of shortening belts as the salt and its thin prekinematic overburden are translated across the arches. The complex salt isopachs deflect salt flow to produce convergent and divergent flow, which, along with flow-velocity gradients, results in the rotation of early formed thrust belts. Rotations of up to 70 degrees were recorded in the most complex model, resulting in transported fold belts with trends that were close to dip parallel, similar to those observed on seismic data from the eastern Gulf of Mexico. Additional zones of shortening are found in and around complex salt pinchouts in the updip zones of the gravity-gliding system. The dynamic nature of these salt-related tectonic systems can result in the downdip translation of fold belts far from the basement topography over which they were created.


ISSN: 2324-8858
EISSN: 2324-8866
Serial Title: Interpretation (Tulsa)
Serial Volume: 5
Serial Issue: 1
Title: The effects of base-salt relief on salt flow and suprasalt deformation patterns; Part 2, Application to the eastern Gulf of Mexico
Affiliation: Bureau of Economic Geology, Austin, TX, United States
Pages: SD25-SD38
Published: 201702
Text Language: English
Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States
References: 14
Accession Number: 2017-037189
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. block diags., sects., sketch maps
N26°00'00" - N30°30'00", W90°00'00" - W82°00'00"
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: 201721
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