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Heterogeneous hydrofracture development and accretionary fault dynamics

Kevin M. Brown, Barbara Bekins, B. Clennell, D. Dewhurst and G. Westbrook
Heterogeneous hydrofracture development and accretionary fault dynamics
Geology (Boulder) (March 1994) 22 (3): 259-262

Abstract

Ocean Drilling Program observations at many accretionary wedges indicate that fluid flow in low-permeability sediments is focused along faults rich in clay minerals. Recent ring-shear experiments show that shear failure generally reduces permeability in muddy faults to values well below the surrounding sediments and that very little increase occurs in the fault permeability even when continued failure proceeds under steadily reduced effective loads. It is, thus, unlikely that observed focused flow occurs through the matrix of muddy faults, and we suggest that focused flow can only be explained by the development of open fracture systems. The lithostatic fluid pressures necessary for hydrofracturing in weak sediments cannot, however, exist throughout the imbricate thrust system and basal decollement zone because a zero basal shear stress condition would result in regional instability and accretionary wedge collapse. We propose that the regional hydrofracture networks must propagate heterogeneously, leaving relatively strong asperity regions at sublithostatic fluid pressures to balance forces in the wedge in three dimensions. March 1994


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 22
Serial Issue: 3
Title: Heterogeneous hydrofracture development and accretionary fault dynamics
Affiliation: Scripps Institution of Oceanography, La Jolla, CA, United States
Pages: 259-262
Published: 199403
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 24
Accession Number: 1994-025512
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sect.
Secondary Affiliation: University of California at Santa Cruz, Santa Cruz, CA, USA, United StatesUniversity of Birmingham, Birmingham, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 199412
Program Name: ODPOcean Drilling Program
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