Hydrologic controls on the morphology and mechanics of accretionary wedges

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doi: 10.1130/0091-7613(2002)030<0271:HCOTMA>2.0.CO;2
Author(s): Saffer, Demian M.; Bekins, Barbara A.
Author Affiliation(s): Primary:
University of Wyoming, Department of Geology and Geophysics, Laramie, WY, United States
Other:
U. S. Geological Survey, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 30(3), p.271-274. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. 21 refs.; illus.
Summary: At many subduction zones, accretionary complexes form as sediments are offscraped from the subducting plate. Existing mechanical models that treat accretionary complexes as critically tapered wedges of sediment demonstrate that pore pressure controls their taper angle by modifying rock strength. We combine a model of groundwater flow with critical-taper theory to show that permeability and plate-convergence rate are important controls on accretionary wedge geometry through their influence on pore pressure. Low permeability and rapid convergence sustain nearly undrained conditions and shallowly tapered geometry, whereas high permeability and slow convergence result in steep geometry. Our results are generally in good agreement with data from active accretionary complexes, but also illustrate the importance of other factors, such as incoming sediment thickness and stratigraphy. One key implication is that strain rate and hydrologic properties may strongly influence the strength of the crust in a variety of geologic settings.
Year of Publication: 2002
Research Program: ODP Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; 18 Geophysics, Solid-Earth; Accretionary wedges; Atlantic Ocean; Controls; Crust; Drainage; Friction; Geometry; Ground water; Leg 110; Leg 146; Leg 190; Marine sediments; Mechanical properties; Mechanics; Modern analogs; Morphology; North Atlantic; North Pacific; Ocean Drilling Program; Pacific Ocean; Permeability; Plate convergence; Pore pressure; Pore water; Rates; Sediments; Strength; Subduction zones
Coordinates: N153133 N153224 W0584207 W0585106
N341715 N484200 W1200210 W1284300
N313000 N324500 E1351500 E1340000
Record ID: 2002020890
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