Contrasting geothermal regimes of the Barbados ridge accretionary complex

Journal Article · Sun Jun 10 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JB095iB06p08829· OSTI ID:5073573

Langseth, M G; Hobart, M ^[1]; Westbrook, G K ^[2]

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1. Lamont-Doherty Geological Observatory, Palisades, NY (United States)
2. Univ. of Birmingham (England)

Three E-W transects of closely spaced heat flow measurements across the Barbados accretionary complex are reported. One transect, shows that heat flow decreases arcward roughly in proportion to the thickening of the wedge over the actively accreting zone. This decrease is due to the combined thermal effects of the underthrusting oceanic lithosphere and thickening of sediments that have been ingested into the wedge. Except for anomalously high heat flow over a mud volcano on the eastern end of the 100-km transect, fluid expulsion appears to have only a secondary effect on the seafloor heat flow in this region. An increase of heat flow is observed at the western end of the 100-km transect where high-angle arcward vergent thrusting is occurring. The authors attribute this increase primarily to a decrease in the arcward thickening of wedge material, and heat generated by friction on the decollement. In strong contrast a short line of stations at 15{degree}30{prime}N found anomalously high heat flow with large variability over the most recently accreted material and also in the adjacent basin. The thermal regime in the vicinity of this transect is dominated by a string flow of pore fluids along the decollement and upward flow along fault planes in the toe of the wedge and adjacent basin sediments. Heat transport by pore fluids also appears to dominate the subfloor thermal regime in a zone near 13{degree}50{prime}N. The thermal effects of dewatering of the sediments by upward diffusive flow were examined using a simple one-dimensional model, which showed that the resulting effects are too small to produce detectable heat flow anomalies. Consequently, the flow of fluids must be channelized in subseafloor conduits to produce the observed anomalies in heat flow.

• OSTI ID: 5073573
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:B6; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
BARBADOS
DIMENSIONS
EARTH CRUST
ENERGY TRANSFER
FLOW MODELS
FRICTION
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
GROUND WATER
HEAT FLOW
HEAT TRANSFER
HYDROGEN COMPOUNDS
INTERSTITIAL WATER
ISLANDS
LESSER ANTILLES
MATHEMATICAL MODELS
OCEANIC CRUST
ONE-DIMENSIONAL CALCULATIONS
OXYGEN COMPOUNDS
PLATE TECTONICS
SEDIMENTS
SUBDUCTION ZONES
TECTONICS
THICKNESS
VARIATIONS
VOLCANOES
WATER
WEST INDIES