Remnant-ocean submarine fans: Largest sedimentary systems on Earth

Ingersoll, Raymond V.; Dickinson, William R.; Graham, Stephan A.

doi:10.1130/0-8137-2370-1.191

Cited by 47 publications

(36 citation statements)

References 94 publications

(187 reference statements)

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“…Hundreds of millions of tons of sediment are carried each year for thousands of kilometres along the largest fluvial systems, such as the Amazon, the Ganga‐Brahmaputra or the Yellow River (Hay, ; Milliman & Farnsworth, ). Equally established is the underwater transport of large sediment volumes over similar distances via turbidity currents, such as across the present Bengal and Indus fans or their ancient analogues (Ingersoll et al ., ). Far less documented is the transport of large sediment volumes in the shallow sea, which can cover distances of a thousand kilometres and more under the action of persistent longshore currents.…”

Section: Introductionmentioning

confidence: 99%

Sedimentary processes controlling ultralong cells of littoral transport: Placer formation and termination of the Orange sand highway in southern Angola

et al. 2017

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This study focuses on the causes, modalities and obstacles of sediment transfer in the longest cell of littoral sand drift documented on Earth so far. Sand derived from the Orange River is dragged by swell waves and persistent southerly winds to accumulate in four successive dunefields in coastal Namibia to Angola. All four dunefields are terminated by river valleys, where aeolian sand is flushed back to the ocean; and yet sediment transport continues at sea, tracing an 1800 km long submarine sand highway. Sand drift would extend northward to beyond the Congo if the shelf did not become progressively narrower in southern Angola, where drifting sand is funnelled towards oceanic depths via canyon heads connected to river mouths. Garnet–magnetite placers are widespread along this coastal stretch, indicating systematic loss of the low‐density feldspatho‐quartzose fraction to the deep ocean. More than half of Moçamedes Desert sand is derived from the Orange River, and the rest in similar proportions from the Cunene River and from the Swakop and other rivers draining the Damara Orogen in Namibia. The Orange fingerprint, characterized by basaltic rock fragments, clinopyroxene grains and bimodal zircon‐age spectra with peaks at ca 0·5 Ga and ca 1·0 Ga, is lost abruptly at Namibe, and beach sands further north have abundant feldspar, amphibole‐epidote suites and unimodal zircon‐age spectra with a peak at ca 2·0 Ga, documenting local provenance from Palaeoproterozoic basement. Along with this oblique‐rifted continental margin, beach placers are dominated by Fe–Ti–Cr oxides with more monazite than garnet and thus have a geochemical signature sharply different from beach placers found all the way along the Orange littoral cell. High‐resolution mineralogical studies allow us to trace sediment dispersal over distances of thousands of kilometres, providing essential information for the correct reconstruction of ‘source to sink’ relationships in hydrocarbon exploration and to predict the long‐term impact of man‐made infrastructures on coastal sediment budgets.

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Section: Introductionmentioning

confidence: 99%

Sedimentary processes controlling ultralong cells of littoral transport: Placer formation and termination of the Orange sand highway in southern Angola

et al. 2017

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“…Crustal growth is dominated by the tectonically thickened mafic lower crustal component, which was originally the depositional substrate of the turbidites. On the basis of the published (see references in the Lachlan and Rangitaton sections) and unpublished ( Figure 14 for the Damara example [92]) detrital zircon U-Pb age distributions, most of the sediment in the turbide fans is recycled from adjacent continents and arcs (see [144,145] for other examples).…”

Section: Discussionmentioning

confidence: 99%

Continental Growth and Recycling in Convergent Orogens with Large Turbidite Fans on Oceanic Crust

Foster

Goscombe²

2013

Geosciences

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Convergent plate margins where large turbidite fans with slivers of oceanic basement are accreted to continents represent important sites of continental crustal growth and recycling. Crust accreted in these settings is dominated by an upper layer of recycled crustal and arc detritus (turbidites) underlain by a layer of tectonically imbricated upper oceanic crust and/or thinned continental crust. When oceanic crust is converted to lower continental crust it represents a juvenile addition to the continental growth budget. This two-tiered accreted crust is often the same thickness as average continental crustal and is isostatically balanced near sea level. The Paleozoic Lachlan Orogen of eastern Australia is the archetypical example of a tubidite-dominated accretionary orogeny. The Neoproterozoic-Cambrian Damaran Orogen of SW Africa is similar to the Lachlan Orogen except that it was incorporated into Gondwana via a continent-continent collision. The Mesozoic Rangitatan Orogen of New Zealand illustrates the transition of convergent margin from a Lachlan-type to more typical accretionary wedge type orogen. The spatial and temporal variations in deformation, metamorphism, and magmatism across these orogens illustrate how large volumes of turbidite and their relict oceanic basement eventually become stable continental crust. The timing of deformation and metamorphism recorded in these rocks reflects the crustal thickening phase, whereas post-tectonic magmatism constrains the timing of chemical maturation and cratonization. Cratonization of continental crust is fostered because turbidites represent fertile sources for felsic magmatism. Recognition of similar orogens in the Proterozoic and Archean is important for the evaluation of crustal growth models, particularly for those based on detrital zircon age patterns, because crustal growth by accretion of upper oceanic crust or mafic underplating does not readily result in the addition of voluminous zircon-bearing magmas at the time of accretion. This crust only produces significant zircon when and if it partially melts, which may occur long after accretion

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“…As such we see no evidence for the existence of a continuous carbonate platform in this area during the Permian. Other authors have suggested that the turbidite basin is a remnant basin of the Late Paleozoic Paleo‐Tethyan Ocean between the North China and Yangtze Plates (Yin & Harrison 2000; Ingersoll et al. 2002) or an inherited foreland basin postdating the closure of the Bayan Har oceanic basin (Pan et al.…”

Section: Interpretation and Discussionmentioning

confidence: 99%

“…Recognition of a series of fault‐bound blocks of Permian limestone in the Triassic turbidites suggests that the turbidites were laid on a wide Permian carbonate platform that formed part of the Tethyan ocean (Yin & Zhang 1998). It has also been proposed that the Triassic turbidite basin is a remnant basin between the North China and Yangtze Plates (Yin & Harrison 2000; Ingersoll et al. 2002) or an inherited foreland basin postdating the closure of the Bayan Har oceanic basin (Pan et al.…”

Section: Introductionmentioning

confidence: 99%

Provenance and thermal history of the Bayan Har Group in the western‐central Songpan–Ganzi–Bayan Har terrane: Implications for tectonic evolution of the northern Tibetan Plateau

et al. 2009

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Triassic turbidites dominate the Songpan-Ganzi-Bayan Har (SGBH) terrane of the northern Tibetan Plateau. U-Pb dating on single detrital zircon grains from the Triassic Bayan Har Group turbidites yield peaks at 400-500 m.y., 900-1000 m.y., 1800-1900 m.y., and 2400-2500 m.y., These results are consistent with recently published U-Pb zircon ages of pre-Triassic bedrock in the East Kunlun, Altyn, Qaidam, Qilian and Alaxa areas to the north, suggesting that provenance of the Bayan Har Group may include these rocks. The similarities in the compositions of the lithic arkosic sandstones of the Bayan Har Group with the sandstones of the Lower-Middle Triassic formations in the East Kunlun terrane to the north also suggests a common northern provenance for both. A well exposed angular unconformity between the Carboniferous-Middle Permian mélange sequences and the overlying Upper Permian or Triassic strata indicates that regional deformation occurred between the Middle and Late Permian. This deformation may have been the result of a soft collision between the Qiangtang terrane and the North China Plate and the closure of the Paleo-Tethyan oceanic basin. The Bayan Har Group turbidites were then deposited in a re-opened marine basin on a shelf environment. Fission-track dating of detrital zircons from the Bayan Har Group sandstones revealed pre-and post-depositional age components, suggesting that the temperatures did not reach the temperatures necessary to anneal retentive zircon fission tracks (250-300°C). A 282-292 m.y. peak age defined by low U concentration, retentive zircons likely reflects a northern granitic source. Euhedral zircons from two lithic arkoses with abundant volcanic fragments in the southern area yielded a~237 m.y. zircon fission track (ZFT) peak age, likely recording the maximum age of deposition. A dominant postdepositional 170-185 m.y. ZFT peak age suggests peak temperatures were reached in the Early Jurassic. Some samples appear to record a younger thermal event at~140 m.y., a short lived event that apparently affected only the least retentive zircons.i ar_666 444..466

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Remnant-ocean submarine fans: Largest sedimentary systems on Earth

Cited by 47 publications

References 94 publications

Sedimentary processes controlling ultralong cells of littoral transport: Placer formation and termination of the Orange sand highway in southern Angola

Sedimentary processes controlling ultralong cells of littoral transport: Placer formation and termination of the Orange sand highway in southern Angola

Continental Growth and Recycling in Convergent Orogens with Large Turbidite Fans on Oceanic Crust

Provenance and thermal history of the Bayan Har Group in the western‐central Songpan–Ganzi–Bayan Har terrane: Implications for tectonic evolution of the northern Tibetan Plateau

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