Peru-Chile Trench Sediments and Sea-Floor Spreading

Scholl, David W.; Christensen, Mark N.; Huene, Roland von; Marlow, Michael S.

doi:10.1130/0016-7606(1970)81[1339:ptsass]2.0.co;2

Cited by 170 publications

(76 citation statements)

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“…1) the Peru-Chile trench can be divided into three morphologic segments which are separated by tectonic discontinuities (Thornburg and Kulm 1987a, b). North of 27.5°S the trench reaches its greatest depth of up to 8000 m. Because sediment infill is very thin, from 27.5°S to 33°S a continuous sediment wedge partially fills the trench up to water depths of approximately 5500 m (Scholl et al 1970). Further south the sediment fill increases markedly up to 2 km thickness.…”

Section: Study Areamentioning

confidence: 94%

“…They are sparse to absent north of 33°S but become more frequent further south where big submarine fans are developed on the lower continental slope and in the trench (Thornburg and Kulm 1987a, b). North of 33°S the shelf is extremely narrow averaging only 10 km; further south it widens to an average of 20-30 km and reaches up to 150 km width south of 42°S (Scholl et al 1970). The shelf break is generally located at water depths between 150 and 200 m.…”

Section: Study Areamentioning

confidence: 99%

“…The ascent from the trench is often broken by structural troughs which form sediment traps (Scholl et al 1970). Submarine canyons beginning at the shelf break occur off the mouth of major rivers.…”

Section: Study Areamentioning

confidence: 99%

“…North of 27.5°S Chile is divided from west to east into the Coastal Range, a longitudinal depression, and the Andes, which form the present volcanic arc (Scholl et al 1970). The Coastal Range exhibits an abrupt morphological rise from sea level to elevations of 2000-2500 m. It consists primarily of Mesozoic intermediate calc-alkaline plutonites and subordinately of metamorphites and basaltic to andesitic volcanics (Zeil 1986;Thornburg and Kulm 1987b).…”

Section: Continental Geology and Morphologymentioning

confidence: 99%

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Terrigenous sediment supply along the Chilean continental margin: modern regional patterns of texture and composition

Lamy

Hebbeln

Wefer

1998

Geologische Rundschau

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The regional patterns of texture and composition of modern continental slope and pelagic sediments off Chile between 25°S and 43°S reflect the latitudinal segmentation of geological, morphological, and climatic features of the continental hinterland. Grain-size characteristics are controlled by the grain-size of source rocks, the weathering regime, and mode of sediment input (eolian off northern Chile vs fluvial further south). Bulk-mineral assemblages reveal a low grade of maturity. Regional variations are governed by the source-rock composition of the different geological terranes and the relative source-rock contribution of the Coastal Range and Andes, as controlled by the continental hydrology. The relative abundance of clay minerals is also predominantly influenced by the source-rock composition and partly by continental smectite neoformation. Latitudinal variations of illite crystallinities along the Chilean continental slope (and west of the Peru--Chile trench) clearly reflect modifications of the weathering regime which correspond to the strong climatic zonation of Chile.

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Section: Study Areamentioning

confidence: 94%

Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Continental Geology and Morphologymentioning

confidence: 99%

See 2 more Smart Citations

Terrigenous sediment supply along the Chilean continental margin: modern regional patterns of texture and composition

Lamy

Hebbeln

Wefer

1998

Geologische Rundschau

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“…Superposed on annual periodic rainfall variation, the region around 28°S is subjected to episodic variations from arid to semiarid conditions due to increased moisture transport from the south controlled by a northward shift of the Southern Westerlies during glacial periods (e.g. Scholl et al, 1970;Heusser, 1989;Clapperton, 1993;Veit, 1996;Lamy et al, 1998;Lamy et al, 2000;Jenny et al, 2002;Romero et al, 2006;Hebbeln et al, 2007). Less extensive shifts of the Westerlies have occurred on shorter timescales in the recent geologic past, i.e.…”

Section: Climatic Settingmentioning

confidence: 99%

The topographic imprint of a transient climate episode: the western Andean flank between 15·5° and 41·5°S

Rehak

Bookhagen

Strecker

et al. 2010

Earth Surf Processes Landf

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Mountain-range topography is determined by the complex interplay between tectonics and climate. However, often it is not clear to what extent climate forces topographic evolution and how past climatic episodes are reflected in relief. The Andes are a tectonically active mountain belt encompassing various climatic zones with pronounced differences in rainfall and glacier extent under similar plate-boundary conditions. In the Central to South-Western Andes climatic zones range from hyperarid desert with mean annual rainfall of 5 mm/a (22.5°S) to year-round humidity with 2500 mm/a (40°S). The Andes thus provide a unique setting for investigating the relationship between climate and topography. We present the analysis of 120 catchments along the western Andean watersheds between 15.5° and 41.5°S, which is based on SRTMV3-90m data and the new medium-resolution rainfall (TRMM) dataset. For each basin, we extracted geometry, relief, and climate parameters to test whether Andean topography shows a climatic imprint and to analyze how climate influences relief. Our data document that elevation and relief decrease with increasing rainfall and descending snowline elevation. Furthermore, we show that local relief reaches high values of 750 m in a zone between 28° to 35°S. During Pleistocene glacial stages this region was affected by the northward shifting southern hemisphere Westerlies, which provided moisture for valley-glacier formation and extended glacial coverage as well as glacial erosion. In contrast, the southern regions between 35° to 40°S receive higher rainfall and have a lower local relief of 200 m, probably related to an increased drainage density. We distinguish two different, climatically-controlled mechanisms shaping topography: (1) fluvial erosion by prolonged channel-hillslope coupling, which smoothes relief, and (2) erosion by valley glaciers that generates relief. Finally, our results suggests that the catchment-scale relief of the Andes between 28° to 35°S is characterized by a pronounced transient component reflecting past climatic conditions.

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References

2013

The Geophysics of the Pacific Ocean Basin and Its Margin

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Peru-Chile Trench Sediments and Sea-Floor Spreading

Cited by 170 publications

References 0 publications

Terrigenous sediment supply along the Chilean continental margin: modern regional patterns of texture and composition

Terrigenous sediment supply along the Chilean continental margin: modern regional patterns of texture and composition

The topographic imprint of a transient climate episode: the western Andean flank between 15·5° and 41·5°S

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