Extensional rupture of oceanic crust in the Chile Trench

Schweller, W. J.; Kulm, L. D.

doi:10.1016/0025-3227(78)90022-1

Cited by 39 publications

(27 citation statements)

References 21 publications

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“…When fault throw is small compared to the thickness of the overlying sediments, the position of the décollement is not influenced by the fault structure of the downgoing plate (Schweller and Kulm, 1978;Hilde, 1983;von Huene and Scholl, 1991). Offshore of Nicaragua, the large basement faults minimize or inhibit the development of a décollement within the subducting sediment package.…”

Section: Discussionmentioning

confidence: 99%

“…Basement roughness with relief the same size as the overlying subducting sediment thickness can potentially act to inhibit relocation of the décollement within the sediment column, preserving shallow sediment layers for incorporation into arc magmas (Schweller andKulm, 1978, Hilde, 1983;von Huene and Scholl, 1991).…”

Section: Background and Motivationmentioning

confidence: 99%

“…If the thickness of the subducting sediment column is comparable to fault throw and does not change along strike, then fault relief could enhance subduction of the downgoing sediment; offscraping or underplating may be more prevalent when basement faults in the downgoing plate are small in comparson with the overlying sediment thickness (Schweller and Kulm, 1978;Hilde, 1983). We examined swath bathymetry data together with new and existing MCS data to constrain the varation in Cocos plate basement fault structure along strike of the margin and its possible impact on surface sediment subduction and lOBe recycling.…”

Section: Geologic Settingmentioning

confidence: 99%

“…Conversely, the lack of large basement relief in the downgoing plate might explain the lack of lOBe in Costa Rica. Offscraping or underplating may be more prevalent when the extensional fault formation in the downgoing plate is minimal or small in comparison with the overlying sediment thickness (Schweller and Kulm, 1978;Hilde andSharman, 1978, Hilde, 1983).…”

Section: Crustal Faulting In the Cocos Plate At The Middle America Trmentioning

confidence: 99%

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Subduction dynamics at the middle America trench : new constraints from swath bathymetry, multichannel seismic data, and 10BE

Kelly¹

2003

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Section: Discussionmentioning

confidence: 99%

Section: Background and Motivationmentioning

confidence: 99%

Section: Geologic Settingmentioning

confidence: 99%

Section: Crustal Faulting In the Cocos Plate At The Middle America Trmentioning

confidence: 99%

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Subduction dynamics at the middle America trench : new constraints from swath bathymetry, multichannel seismic data, and 10BE

Kelly¹

2003

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“…Variations of the imbricate thrust model, proposed on the basis of geophysical studies of forearc areas (Karig, 1974;Seely et al, 1974;Karig and Sharman, 1975), explain the principal drilling results along some active margin transects Moore, Biju-Duval, et al, 1982), but are inapplicable in others (Hussong and Uyeda, 1982;von Huene, et al, 1980). The ultimate fate of sediments that enter subduction zones ranges from accretion by various mechanisms to subduction, and data from several margins have been interpreted by some workers to suggest tectonic erosion of the forearc by the incoming ocean crust (Schweller and Kulm, 1978;Hussong and Uyeda, 1982).…”

Section: Introductionmentioning

confidence: 99%

Structural Features in Cores from the Nankai Trough, Deep Sea Drilling Project Leg 87A

Lundberg¹,

Karig²

1986

Initial Reports of the Deep Sea Drilling Project

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Small-scale structures in Leg 87A cores provide details on the fold-and-thrust-style deformation produced by subduction at the Nankai Trough. Bedding dips at Holes 583B, 583C, and 583D define a steep homocline interpreted as the seaward limb of hanging-wall anticline formed over a thrust ramp. A thin interval of steep dips between 150 and 160 m is suggestive of drag along a hanging-wall fault splay. A balanced reconstruction of postulated structure, assuming plane strain, indicates 280 m of horizontal displacement along the thrust. Quantitatively less important mechanisms of shortening include minor reverse faults, broad open folding, and kink bands. Kinks are dark planar surfaces developed in the cored sediment, along which primary features have been rotated in the sense of a reverse fault. Specifically, kinks are made up of multiple strands that are sharply bounded and regularly arranged domains of strongly aligned phyllosilicates. They are consistently high-angle features, geometrically and kinematically similar to high-angle reverse faults defined seismically in the protothrust zone in front of the thrust belt. We suggest that kinks formed in an analogous setting, when the section penetrated at Site 583 occupied the landward portion of the trench.A reference section drilled at Site 582 in the trench floor provides a control for structural features at Site 583. Aside from a bedding-parallel fissility, the only structures observed in cores from Site 582 are healed normal faults and vein structure. These are present only in Shikoku Basin hemipelagic mudstones that underlie trench deposits, and probably reflect extension caused by flexure of the Philippine Plate. These structures are not present in cores from Site 583, which did not penetrate through the uplifted trench-fill section.

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Deep‐Sea Polychaetous Annelida from Central America to the Antarctic Peninsula and South Sandwich Islands

Maurer

Williams

1988

Intl Review of Hydrobiology

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Based on the 1958 Vema cruise and the 1965 Anton Bruun cruise 11 off the west coast of Central America and sout'h through the islands ezst of the tip of South America, 143 trawl samples were examined for abyssal polychaetous annelida. The cruise tracks designated 7 major areas: Central America (I), Ecuador-Peru (11), Central and Southern Chile (111), Chile and the Magellan Strait (IV), Tierra del Fuego (V), the Island Complex (Falkland, South Georgia and South Sandwich Islands) (VI), the Dribke Strait and Antarctic Peninsula (VII). The collections yielded 7,015 individuals and 322 species from 52 families. The relatively small number of species was attributed mainly to sampling effort, collecting gear and processing techniques.Each major area was characterized in terms of the number of individuals, the number of species, mean number of individuals, mean number of species and mean H', S R , J' and DI. Species diversity was significantly higher in Central America (I) than in the other areas. The relationships between biotic and abiotic measures (dept'h and areas of upwelling) were examined. There were no significant associations for the entire data base with depth. Moreover, there was no association between abundance of polycliaetes and areas of upwelling which was hypothesized. I n fact, relative abundance was highest in the deepest portions of Central America (I) (Guatemala Basin) and Ecuador-Peru (11) (Milne-Edwards Deep) compared to shallower areas closer to areas of upwelling. Quantitative collecting gear and refined processing techniques will be required to more accurately address these relationship?. Dominant families were identified in terms of number of sFecirs and number of individuals. These families conformed well with world wide generalizations of dominant families. Dominant, species were identified based on the Biological Index Value. The top twenty or dominant species for each major brea were identified. A number of these dominant species occurred widely throughout the mnjor areas. The dominant species for the entire data set were determined. I n general these species were very eurybathic which was consistent with other worldwide depth distributions of abyssal polychaetes.

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Extensional rupture of oceanic crust in the Chile Trench

Cited by 39 publications

References 21 publications

Subduction dynamics at the middle America trench : new constraints from swath bathymetry, multichannel seismic data, and 10BE

Subduction dynamics at the middle America trench : new constraints from swath bathymetry, multichannel seismic data, and 10BE

Structural Features in Cores from the Nankai Trough, Deep Sea Drilling Project Leg 87A

Deep‐Sea Polychaetous Annelida from Central America to the Antarctic Peninsula and South Sandwich Islands

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