Consolidation patterns during initiation and evolution of a plate-boundary decollement zone; northern Barbados accretionary prism

Borehole logs from the northern Barbados accretionary prism show that the plate-boundary decollement initiates in a low-density radiolarian claystone. With continued thrusting, the decollement zone consolidates, but in a patchy manner. The logs calibrate a three-dimensional seismic reflection image...

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Bibliographic Details
Published in:Geology (Boulder) 1998-09, Vol.26 (9), p.811-814
Main Authors: Moore, J. Casey, Klaus, Adam, Bangs, Nathan L, Bekins, Barbara A, Bücker, Christian J, Brückmann, Warner, Erickson, Stephanie N, Hansen, Olav, Horton, Thomas, Ireland, Peter, Major, Candace Olson, Moore, Gregory F, Peacock, Sheila, Saito, Saneatsu, Screaton, Elizabeth J, Shimeld, John W, Stauffer, Philip Henry, Taymaz, Tuncay, Teas, Philip A, Tokunaga, Tomochika
Format: Article
Language:English
Subjects:
accretionary wedges
Atlantic Ocean
Barbados Ridge
calibration
Cenozoic
clastic rocks
clay mineralogy
claystone
consolidation
Cretaceous
decollement
density logging
faults
geophysical methods
geophysical surveys
Geophysics
Leg 110
Leg 156
Leg 171
Leg 171A
marine sediments
Mesozoic
North Atlantic
Ocean Drilling Program
Oceanography
ODP Site 1044
ODP Site 1045
ODP Site 1046
ODP Site 1047
ODP Site 1048
ODP Site 672
ODP Site 948
plate boundaries
Plate tectonics
reflection methods
sedimentary rocks
sedimentation rates
sediments
seismic methods
solid Earth (tectonophysics)
surveys
three-dimensional models
thrust faults
well-logging
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Summary:Borehole logs from the northern Barbados accretionary prism show that the plate-boundary decollement initiates in a low-density radiolarian claystone. With continued thrusting, the decollement zone consolidates, but in a patchy manner. The logs calibrate a three-dimensional seismic reflection image of the decollement zone and indicate which portions are of low density and enriched in fluid, and which portions have consolidated. The seismic image demonstrates that an underconsolidated patch of the decollement zone connects to a fluid-rich conduit extending down the decollement surface. Fluid migration up this conduit probably supports the open pore structure in the underconsolidated patch.
ISSN:0091-7613
1943-2682
DOI:10.1130/0091-7613(1998)026<0811:CPDIAE>2.3.CO;2