Multibeam bathymetric survey and high resolution seismic investigations on the Barbados Ridge complex (Eastern Caribbean): A key to the knowledge and interpretation of an accretionary wedge

Biju-Duval, B.; Quellec, Patrick Le; Mascle, A.; Renard, Vincent; Valery, P.

doi:10.1016/0040-1951(82)90070-1

Cited by 138 publications

(56 citation statements)

References 3 publications

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“…This contrasts with the southern part of the complex, where the sedimentary layer involved in the deformation is thicker and the structures broader, forming large anticlines underlain by thrusts, as shown by SE ABE AM, seismic profiles (Biju-Duval et al, 1982;Chase and Bunce, 1969;Peter and Westbrook, 1976), and GLORIA (Stride et al, 1982).…”

Section: Tiburon Risementioning

confidence: 90%

The Relief of the Oceanic Basement and the Structure of the Front of the Accretionary Complex in the Region of Sites 541, 542, and 543

Mauffret¹,

Westbrook²,

Truchan³

et al. 1984

Initial Reports of the Deep Sea Drilling Project

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The shape of the surface of the oceanic igneous basement beneath the accretionary complex is produced by superimposition of ridges and troughs, related to WNW-trending fracture zones, upon the downward flexure of lithosphere into the subduction zones. The ocean crust is Upper Cretaceous, as determined by identification of oceanic magnetic anomalies and the polarity of magnetic anomalies associated with the fracture zones. The magnetic polarity boundary associated with Anomaly 34 lies a little to the west of Site 543. The forward growth of the accretionary complex is related to the amount of sediment accreted. This is in turn broadly related to the thickness of the sediment on the ocean floor, which is locally controlled by basement topography. Consequently, there are significant changes in position and trend of the front of the complex where it crosses ridges and troughs. Growth at the front of the complex is controlled by the level at which a décollement forms in the sediments, and this is only indirectly related to sediment thickness. This dé-collement shows local stratigraphic control, so small changes in basement topography beneath the décollement do not influence the accretionary complex. Seismic velocities in the accretionary complex and in the sediments on the ocean floor, determined from sonobuoys, are not sufficiently unambiguous to show whether there are, in the velocity structure of the sediments, any major changes from that which would be expected from greater compaction with depth.

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Section: Tiburon Risementioning

confidence: 90%

The Relief of the Oceanic Basement and the Structure of the Front of the Accretionary Complex in the Region of Sites 541, 542, and 543

Mauffret¹,

Westbrook²,

Truchan³

et al. 1984

Initial Reports of the Deep Sea Drilling Project

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“…Seismic-reflection profiles across the forearc region of the Barbados Ridge system provide evidence for considerable deformation of accreted sedimentary sequences (see Peter and Westbrook, 1976;Biju-Duval et al, 1982;Westbrook and Smith, 1983;Speed et al, 1984;Valery et al 1985;Mascle et al, this volume). The combined results of DSDP Leg 78A (Biju-Duval, and and ODP Leg 110 provide an unprecedented amount of information about the details of accretion and allow the verification of seismic interpretations.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Accretion and Subsequent Thickening in the Barbados Ridge Accretionary Complex: Balanced Cross Sections across the Wedge Toe

Brown¹,

Mascle²,

Behrmann³

1990

Proceedings of the Ocean Drilling Program

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Detailed analysis of ODP Leg 110 cores provides evidence for a complex structural evolution of the frontal thrust system of the Barbados Ridge accretionary wedge. Thrust faulting and back rotation are the dominant thickening mechanisms within 5 km of the toe of the wedge. Folding and duplex formation are only secondary thickening processes at this point. Estimates of shortening across the frontal 5 km of the wedge vary depending on the balancing technique used. Ignoring the affects of compaction, line-balanced sections suggest 26-36% tectonic shortening, whereas simple volume balanced sections indicate 32% shortening. When a potential average 14% volume loss is considered, the volume-balance estimates of shortening rise to nearer 40%.By 12 km from the front (Site 673), large-scale folding, with the development of overturned sections, becomes a significant thickening process. This folding is followed by the development of low-angle faults that cut out stratigraphic section at around 18 km from the toe (Site 674). These faults are interpreted as out-of-sequence thrusts that cross-cut and dismember an already complexly deformed wedge. The out-of-sequance thrusts are found in a region of the wedge where arc-dipping, low-angle reflectors become prominent on seismic reflection profiles.The current basal decollement zone (to the east of Site 674) lies in the lower Miocene section. Oligocene and Eocene strata are thrust undeformed beneath the wedge for at least 12-18 km (and perhaps farther). The presence of Oligocene and Eocene material within the wedge is, therefore, evidence of a different basal decollement geometry in the past. This different geometry could have entailed either: (1) an earlier phase of frontal off-scraping, with a decollement zone at a lower stratigraphic level; or (2) duplex formation and underplating of part of the Oligocene and Eocene section. We suggest that a mechanism of underplating is the best explanation for the general structural configuration observed at Site 674. If this is the case, then on ODP Leg 110 we made the first penetration of an underplated section in ODP or DSDP history.The overall progression in structural style across the accretionary wedge reflects the need for continuous shape adjustments to maintain a stable critical taper during progressive accretion. Erosion of material from the slope of the wedge at Sites 673 and 674 may have had an important affect on the structural development of the wedge. It is important to note that erosion becomes significant in the region of the wedge where underplating and out-of-sequence thrusting is proposed to have occurred.

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“…The fine-scale surface morphology of the Leg 78A area contrasts with the broad linear highs and lows (large thrusts and related folds) of the area south of 12°30' (Biju-Duval et al, 1982;Figs, 4 and 11). However, the morphology of the Leg 78A area is comparable with that at about 13°N, where westward-dipping reflectors are interpreted as low-angle thrusts (Westbrook et al, this volume).…”

Section: Interpretation Of Structural Geometry Site Survey Data and Smentioning

confidence: 84%

“…1 and 2). Both the arching and uplift of the Quaternary coral cap of Barbados Island (Speed and Larue, 1982) and the seismically documented folding and faulting of surface sediments (Mascle et al, in press;Biju-Duval et al, 1982) attest to the youth of the deformation.…”

Section: 'mentioning

confidence: 99%

Tectonic Synthesis, Deep Sea Drilling Project Leg 78A: Structural Evolution of Offscraped and Underthrust Sediment, Northern Barbados Ridge Complex

Moore¹,

Biju-Duval²

1984

Initial Reports of the Deep Sea Drilling Project

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Drilling and seismic reflection data in the Leg 78A area indicate offscraping of approximately the upper 200 m of the incoming sediment section and underthrusting of the subjacent sediment with the ocean crust. Approximately lithostatic fluid pressure was measured in a thrust fault splaying off the décollement separating the offscraped and underthrust sediment packages; this high fluid pressure apparently allows the underthrusting of the coherent sedimentary sequence beneath the décollement. Repetition of nannofossil zones defines at least five thrust or reverse faults in the offscraped sediment package penetrated at Sites 541 and 542. Restoration of the offscraped sections at these drill sites yields original thicknesses similar to the incoming sedimentary section, indicating that all major structural repetitions are recognized. Unfaulting of the drilled section suggests an average convergence rate of 0.7 km/Ma (0.07 cm/yr.). Distributed deformation arcward of the Leg 78A area probably absorbs the remainder of the 20-plus-km/Ma convergence between the Caribbean and North American plates. Thickening of the offscraped sedimentary section above an unbroken décollement landward of the Leg 78A area cannot be the result of underplating but must be explained by continuing imbrication of the offscraped sedimentary packages. The rate of thickening and hence rate of shortening decreases west of the deformation front. Deformation in the accretionary prism appears to be partitioned between small-scale faulting and fabric development, and discrete large-scale faults.The hemipelagic to pelagic section offscraped in the Leg 78A area includes no terrigenous turbidites but does have numerous ash beds derived from the Lesser Antilles volcanic arc. Hence this sequence is dissimilar to siliciclastic-dominated sub aerial terranes inferred to be ancient accretionary complexes. The underthrust sedimentary section is principally pelagic in character. Thrust and reverse faulting and the décollement tend to develop in or adjacent to underconsolidated Miocene smectitic clays, indicating stratigraphic control on faulting.

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Multibeam bathymetric survey and high resolution seismic investigations on the Barbados Ridge complex (Eastern Caribbean): A key to the knowledge and interpretation of an accretionary wedge

Cited by 138 publications

References 3 publications

The Relief of the Oceanic Basement and the Structure of the Front of the Accretionary Complex in the Region of Sites 541, 542, and 543

The Relief of the Oceanic Basement and the Structure of the Front of the Accretionary Complex in the Region of Sites 541, 542, and 543

Mechanisms of Accretion and Subsequent Thickening in the Barbados Ridge Accretionary Complex: Balanced Cross Sections across the Wedge Toe

Tectonic Synthesis, Deep Sea Drilling Project Leg 78A: Structural Evolution of Offscraped and Underthrust Sediment, Northern Barbados Ridge Complex

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