Sedimentary processes on the continental slope off New England

MacIlvaine, Joseph Chad

doi:10.1575/1912/1227

Cited by 10 publications

(5 citation statements)

References 11 publications

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“…This zone is often heterogeneous due to topographic complexity (MacIlvaine & Ross 1979) and exhibits a greater variability of sediment characteristics than deeper sea beds (Bett 2001; Mortensen et al. 2009).…”

Section: Framing Habitats Of Biological Structuresmentioning

confidence: 99%

“…The upper bathyal zone (500-1500 m) This zone is often heterogeneous due to topographic complexity (MacIlvaine & Ross 1979) and exhibits a greater variability of sediment characteristics than deeper sea beds (Bett 2001;Mortensen et al 2009). In some regions, the margins are intersected by submarine canyons (Rowe 1971;Mortensen et al 2009;Ramirez-Llodra et al 2010;Schlacher et al 2010).…”

Section: Framing Habitats Of Biological Structuresmentioning

confidence: 99%

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Biological structures as a source of habitat heterogeneity and biodiversity on the deep ocean margins

et al. 2010

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Biological structures exert a major influence on species diversity at both local and regional scales on deep continental margins. Some organisms use other species as substrates for attachment, shelter, feeding or parasitism, but there may also be Mutual benefits from the association. Here, we highlight the structural attributes and biotic effects of the habitats that corals, sea pens, sponges and xenophyophores offer other organisms. The environmental setting of the biological structures influences their species composition. The importance of benthic species as substrates seems to increase with depth as the complexity of the surrounding geological substrate and food supply decline. There are marked differences in the degree of mutualistic relationships between habitat-forming taxa. This is especially evident for scleractinian corals, which have high numbers of facultative associates (commensals) and few obligate associates (mutualists), and gorgonians, with their few commensals and many obligate associates. Size, flexibility and architectural complexity of the habitat-forming organism are positively related to species diversity for both sessile and mobile species. This is mainly evident for commensal species sharing a facultative relationship with their host. Habitat complexity is enhanced by the architecture of biological structures, as well as by biological interactions. Colony morphology has a great influence on feeding efficiency for suspension feeders. Suspension feeding, habitat-forming organisms modify the environment to optimize their food uptake. This environmental advantage is also passed on to associated filter-feeding species. These effects are poorly understood but represent key points for understanding ecosystems and biodiversity on continental margins. In this paper we explore the contributions of organisms and the biotic structures they create (rather than physical modifications) to habitat heterogeneity and diversity on the deep continental margins

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Section: Framing Habitats Of Biological Structuresmentioning

confidence: 99%

Section: Framing Habitats Of Biological Structuresmentioning

confidence: 99%

Biological structures as a source of habitat heterogeneity and biodiversity on the deep ocean margins

et al. 2010

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“…Piper et al 1976;Tillman et al 1981). Many modern continental slopes have been shown to consist of silts and sandy silts, with small-scale irregularities and gullies incised into the slope sediments (MacIlvaine & Ross 1979). Also, modern continental slopes are characterized by abundant sediment slides, ranging from centimetres to tens of metres in thickness (Moore 1961;Lewis 1971;Almagor & Garfunkel 1979;Knebel & Carson 1979), and such soft-sediment deformation appears to have contributed to substantial amounts of the postulated ancient continental slope successions (Doyle & Pilkey 1979).…”

mentioning

confidence: 99%

Facies, facies-associations and sediment transport/deposition processes in a late Precambrian upper basin-slope/pro-delta,, Finnmark, N. Norway

Pickering

1984

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Summary The lower Naeringselva Member of the 2.5 to 3.5 km thick Båsnaering Formation varies from 60 to 540 m thick, and is part of the 9 km thick late Precambrian Barents Sea Group cropping out on Varanger Peninsula, north-east Finnmark, N. Norway. It is underlain by a minimum 3.2 km of submarine fan deposits and passes up into delta front and fluvio-deltaic deposits of the Båsnaering Formation. Within the lower Naeringselva Member (LNM) four main facies are recognized: parallel-laminated mudstone; current-rippled siltstone; structureless mudstone, and wave-rippled fine-grained sandstone. Soft sediment deformation was abundant as slide, slump and in situ disturbed layers up to tens of metres thick. Erosional-depositional discordances are evident between packets of beds. Palaeocurrent data, together with a limited number of slide fold readings, suggest a west to south-westerly source area for the submarine fan, upper basin-slope/pro-delta and delta deposits. The stratigraphic position and sedimentology of the LNM suggests that it forms part of an ancient upper basin-slope/pro-delta, with fan deposits on the lower basin-slope. Apart from sporadic storm events visibly affecting the slope, it was below wave-base. Modern analogues for the LNM are the upper part of continental slopes separating fan from delta deposits, as in the Mississippi Delta-Slope-Fan system.

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“…During the past decade, debris (or slope) aprons have been increasingly observed in many parts of the world's oceans and in ancient sedimentary sequences (Piper, Normark & Ingle, 1976;Piper, Farre & Shor, 1985;Cook, 1979;McIlreath & James, 1979;Buck & Bottjer, 1985;Stow, 1985;Colacicchi & Baldanza, 1986, among others). Debris aprons are commonly formed in canyon-deficient slope and base-of-slope environments, dominated by unchannellized massflow processes such as slide/slump, debris flow and turbidity current (MacIlvaine & Ross, 1979;Hill, 1984;Chough, Jeong & Honza, 1985;Mullins & Cook, 1986;Nelson et a/., 1986;Watts & Garrison, 1986, among others). Instead of orderly sequences of thickening-and thinning-upward fan facies, debris aprons consist of a random distribution of sediment gravity-flow deposits.…”

Section: Introductionmentioning

confidence: 99%

The Hunghae Formation, SE Korea: Miocene debris aprons in a back‐arc intraslope basin

Choe

Chough

1988

Sedimentology

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During early to middle Miocene times a sudden opening of the Ulleung (Tsushima) back‐arc basin in the East Sea (Sea of Japan) led to the development of intraslope basins along the rifted southwestern margin (southeast Korea). Abrupt subsidence resulted in the deposition of the 200 m thick Hunghae Formation (middle Miocene), a sand/mudstone sequence that can be divided into five facies. Facies I (sand and mudstone couplet) and II (coarse sand) are turbiditic in origin, as evidenced by massive, graded, crudely‐layered and parallel‐laminated sand beds. Facies III (homogeneous mudstone) is characterized by various lignite and plant fragments, clastic and biogenic grains that are randomly oriented, suggestive of hemipelagic deposition. Facies IV (chaotic deposit) is characterized by the disruption of beds, the presence of isolated siltstone blocks (or balls) and large clasts in the muddy matrix, indicative of retrogressive rockfall and slide/slump. Facies V (conglomerate) is of debris flow origin, as evidenced by clast‐ and matrix‐supported features, floating large clasts and absence of traction structures. Individual facies are organized into two types of facies association: (1) homogeneous mudstone (facies III) associated randomly with the rest (facies I, II, IV and V), indicative of hemipelagic and episodic sediment‐gravity flow processes, respectively; (2) conglomerate (facies V), coarse sand (facies II) and sand/mudstone couplet (facies I), representing the flow transformation from debris flow to high‐ and low‐concentration turbidity currents. These facies associations are similar in many respects to modern and ancient debris (or slope) aprons found elsewhere. Numerous isolated slide/slump blocks, wedged conglomerates with armoured mudstone balls, discontinuous lignite‐containing sand/mudstone beds, chaotic structure and growth faults suggest that the deposition occurred on a steep slope (intraslope basin) off coalescing fan‐deltas, mainly by unchannellized sediment‐gravity flows. Ancient deposits with irregular facies sequences can be viewed as debris‐apron systems, which provide alternatives to submarine‐fan models in many clastic basins with a line rather than point source.

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Sedimentary processes on the continental slope off New England

Cited by 10 publications

References 11 publications

Biological structures as a source of habitat heterogeneity and biodiversity on the deep ocean margins

Biological structures as a source of habitat heterogeneity and biodiversity on the deep ocean margins

Facies, facies-associations and sediment transport/deposition processes in a late Precambrian upper basin-slope/pro-delta,, Finnmark, N. Norway

The Hunghae Formation, SE Korea: Miocene debris aprons in a back‐arc intraslope basin

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