Tectonics and hydrogeology of the northern Barbados Ridge; results from Ocean Drilling Program Leg 110

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doi: 10.1130/0016-7606(1988)100<1578:TAHOTN>2.3.CO;2
Author(s): Moore, J. Casey; Mascle, Alain; Taylor, Elliott; Andreieff, Patrick; Alvarez, Francis; Barnes, Ross; Beck, Christian; Behrmann, Jan; Blanc, Gerard; Brown, Kevin; Clark, Murlene; Dolan, James F.; Fisher, Andrew; Gieskes, Joris; Hounslow, Mark; McLellan, Patrick; Moran, Kate; Ogawa, Yujiro; Sakai, Toyosaburo; Schoonmaker, Jane; Vrolijk, Peter; Wilkens, Roy H.; Williams, Colin
Author Affiliation(s): Primary:
Univ. Calif., Dep. Earth Sci., Santa Cruz, CA, United States
Other:
Inst. Fr. Pet., France
Tex. A&M Univ., United States
BRGM, France
Lamont-Doherty Geol. Obs., United States
Rosario Geosci. Assoc., United States
Univ. Lille, France
Univ. Giessen, Federal Republic of Germany
Univ. Pierre et Marie Curie, France
Durham Univ., United Kingdom
Univ. South Ala., United States
Univ. Miami, United States
Scripps Inst. Oceanogr., United States
Sheffield Univ., United Kingdom
Petro-Can. Resour., Canada
Bedford Inst. Oceanogr., Canada
Kyushu Univ., Japan
Utsunomiya Univ., Japan
Hawaii Inst. Geophys., United States
Mass. Inst. Technol., United States
Volume Title: Geological Society of America Bulletin
Source: Geological Society of America Bulletin, 100(10), p.1578-1593. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7606 CODEN: BUGMAF
Note: In English. 49 refs.; illus. incl. 1 table, sects., strat. cols., sketch maps
Summary: Drilling near the deformation front of the northern Barbados Ridge cored an accretionary prism consisting of imbricately thrusted Neogene hemipelagic sediments detached from little-deformed Oligocene to Campanian underthrust deposits by a décollement zone composed of lower Miocene to upper Oligocene, scaly radiolarian claystone. Biostrati-graphically defined age inversions define thrust faults in the accretionary prism that correlate between sites and are apparent on the seismic reflection sections. Two sites located 12 and 17 km west of the deformation front document continuing deformation of the accreted sediments during their uplift. Deformational features include both large- and small-scale folding and continued thrust faulting with the development of stratal disruption, cataclastic shear zones, and the proliferation of scaly fabrics. These features, resembling structures of accretionary complexes exposed on land, have developed in sediments never buried more than 400 m and retaining 40% to 50% porosity. A single oceanic reference site, located 6 km east of the deformation front, shows incipient deformation at the stratigraphic level of the décollement and pore-water chemistry anomalies both at the décollement level and in a subjacent permeable sand interval.Pore-water chemistry data from all sites define two fluid realms: one characterized by methane and chloride anomalies and located within and below the décollement zone and a second marked solely by chloride anomalies and occurring within the accretionary prism. The thermogenic methane in the décollement zone requires fluid transport many tens of kilometers arcward of the deformation front along the shallowly inclined décollement surface, with minimal leakage into the overlying accretionary prism. Chloride anomalies along faults and a permeable sand layer in the underthrust sequence may be caused by membrane filtration or smectite dewatering at depth. Low matrix permeability requires that fluid flow along faults occurs through fracture permeability. Temperature and geochemical data suggest that episodic fluid flow occurs along faults, probably as a result of deformational pumping.
Year of Publication: 1988
Research Program: DSDP Deep Sea Drilling Project
ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 07 Marine Geology and Oceanography; 18 Geophysics, Solid-Earth; Atlantic Ocean; Barbados Ridge; Cenozoic; Chloride ion; Chlorine; Cores; Decollement; Deep Sea Drilling Project; Displacements; Faults; Folds; Geochemistry; Halogens; Heat flow; Imbricate tectonics; Leg 110; Marine sediments; Mid-ocean ridges; North American Atlantic; North Atlantic; Ocean Drilling Program; Plate tectonics; Pore water; Porosity; Sediments; Tectonics; Tectonophysics; Thrust faults
Coordinates: N153000 N154000 W0583500 W0585300
Record ID: 1988071097
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