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Title: Physical models of structural patterns above salt diapirs

Abstract

Dry clay models were used to study fault systems that develop in strata above domal uplifts. Contemporaneous deposition and deformation was modeled by incrementally uplifting a model diapir and depositing additional layers of dry clay on the deformed strata. Variables observed to control structural patterns that developed in the arched and extended strata include: (1) the nature of the contact between the model diapir and the overlying strata, (2) the thickness of the pre-uplift sequence, and (3) the rate of sedimentation with respect to the rate of diapir uplift. Boundary conditions between the model diapir and overlying strata proved very critical in controlling fault patterns. Naturally occurring salt diapir-related faults systems seem best duplicated experimentally by allowing the pre-uplift strata to slide passively along the sides of the uplifting diapir, modeling a non-welded contact. With uplift, two related but distinct systems of extensional faults developed above the crest of the model diapir: (1) a surface-breaking graben complex bounding by inward-dipping normal faults and rooted in the upper levels of the pre-uplift strata, and (2) a blind system of normal faults rooted to the crest of the diapir. The surface-breaking graben complex was observed only in experiments with thin pre-uplift sequencesmore » (pre-uplift thickness equaled one-half diapir diameter) and intermediate-thickness pre-uplift sequences (pre-uplift thickness equaled one-and-a-half times diapir diameter). In the thin pre-uplift experiments, the graben complexes were rooted to the top of the diapir. In the intermediate thickness pre-uplift experiments, inwards-dipping, graben-bounding normal faults intersected and diverged at depth, forming conjugate fault sets with grabens situated immediately above pyramid-shaped horsts.« less

Authors:
;  [1]
  1. Univ. of Alabama, Tuscaloosa (USA)
Publication Date:
OSTI Identifier:
5991467
Report Number(s):
CONF-9010204-
Journal ID: ISSN 0149-1423; CODEN: AABUD
Resource Type:
Conference
Journal Name:
AAPG Bulletin (American Association of Petroleum Geologists); (USA)
Additional Journal Information:
Journal Volume: 74:9; Conference: Gulf Coast Association of Geological Societies and Gulf Coast Section of SEPM (Society of Economics, Paleontologists, and Mineralogist) meeting, Lafayette, LA (USA), 17-19 Oct 1990; Journal ID: ISSN 0149-1423
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; 58 GEOSCIENCES; SALT DEPOSITS; GEOLOGIC MODELS; DEPOSITION; GEOLOGIC FAULTS; GEOLOGIC DEPOSITS; GEOLOGIC FRACTURES; GEOLOGIC STRUCTURES; 020200* - Petroleum- Reserves, Geology, & Exploration; 580000 - Geosciences

Citation Formats

Brewer, R C, and Groshong, Jr, R H. Physical models of structural patterns above salt diapirs. United States: N. p., 1990. Web.
Brewer, R C, & Groshong, Jr, R H. Physical models of structural patterns above salt diapirs. United States.
Brewer, R C, and Groshong, Jr, R H. 1990. "Physical models of structural patterns above salt diapirs". United States.
@article{osti_5991467,
title = {Physical models of structural patterns above salt diapirs},
author = {Brewer, R C and Groshong, Jr, R H},
abstractNote = {Dry clay models were used to study fault systems that develop in strata above domal uplifts. Contemporaneous deposition and deformation was modeled by incrementally uplifting a model diapir and depositing additional layers of dry clay on the deformed strata. Variables observed to control structural patterns that developed in the arched and extended strata include: (1) the nature of the contact between the model diapir and the overlying strata, (2) the thickness of the pre-uplift sequence, and (3) the rate of sedimentation with respect to the rate of diapir uplift. Boundary conditions between the model diapir and overlying strata proved very critical in controlling fault patterns. Naturally occurring salt diapir-related faults systems seem best duplicated experimentally by allowing the pre-uplift strata to slide passively along the sides of the uplifting diapir, modeling a non-welded contact. With uplift, two related but distinct systems of extensional faults developed above the crest of the model diapir: (1) a surface-breaking graben complex bounding by inward-dipping normal faults and rooted in the upper levels of the pre-uplift strata, and (2) a blind system of normal faults rooted to the crest of the diapir. The surface-breaking graben complex was observed only in experiments with thin pre-uplift sequences (pre-uplift thickness equaled one-half diapir diameter) and intermediate-thickness pre-uplift sequences (pre-uplift thickness equaled one-and-a-half times diapir diameter). In the thin pre-uplift experiments, the graben complexes were rooted to the top of the diapir. In the intermediate thickness pre-uplift experiments, inwards-dipping, graben-bounding normal faults intersected and diverged at depth, forming conjugate fault sets with grabens situated immediately above pyramid-shaped horsts.},
doi = {},
url = {https://www.osti.gov/biblio/5991467}, journal = {AAPG Bulletin (American Association of Petroleum Geologists); (USA)},
issn = {0149-1423},
number = ,
volume = 74:9,
place = {United States},
year = {Sat Sep 01 00:00:00 EDT 1990},
month = {Sat Sep 01 00:00:00 EDT 1990}
}

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