Seismic evidence of current-controlled sedimentation in the Belgica Mound Province, upper Porcupine Slope, southwest of Ireland
Van Rooij, D.; De Mol, B.; Huvenne, V.; Ivanov, M.; Henriet, J.-P. (2003). Seismic evidence of current-controlled sedimentation in the Belgica Mound Province, upper Porcupine Slope, southwest of Ireland. Mar. Geol. 195(1-4): 31-53. https://dx.doi.org/10.1016/S0025-3227(02)00681-3 In: Marine Geology. Elsevier: Amsterdam. ISSN 0025-3227; e-ISSN 1872-6151, more Also appears in:Ivanov, M.K.; Kenyon, N.H.; Suzyumov, A.E.; Woodside, J.M. (Ed.) (2003). Sedimentary processes and seafloor hydrocarbon emission on deep European continental margins: a selection of papers mainly presented at the congress on Geological Processes on Deepwater European Margins, held in Moscow, Russia, February 2001, in celebration of the 10th Anniversary of the Training Through Research Programme. Marine Geology, 195(1-4). Elsevier: Amsterdam. 324 pp., more |  |
| Keywords | Current observations
Earth sciences > Geology > Stratigraphy > Seismic stratigraphy
Geological time > Phanerozoic > Geological time > Cenozoic
Marine engineering
Motion > Sediment movement > Sediment gravity flows > Turbidity currents
Motion > Water motion > Water currents > Bottom currents
Physics > Mechanics > Fluid mechanics > Hydrodynamics
Sedimentation
Sediments > Clastics > Turbidites
Submarine geology
Topographic features > Banks (topography)
Topographic features > Submarine features > Continental slope
Topography > Topography (geology) > Bottom topography
Transport > Sediment transport
Water waves > Internal waves > Internal tides
A, Atlantic [Marine Regions]; ANE, Porcupine Seabight [Marine Regions]
Marine/Coastal | | Author keywords | bottom current; turbidity current; seismic stratigraphy; Northeast Atlantic; Porcupine Seabight; Cenozoic; mound |
| Authors | | Top | | - Ivanov, M.
- Henriet, J.-P., more
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| Abstract | The Porcupine Seabight is an embayment that takes a particular position in the NE Atlantic slope. Sonographs, a few current measurements and hydrodynamic modelling suggest the presence of a strong northward-flowing bottom current, locally enhanced by internal tides, affecting the eastern slope of the Seabight. At this location a province of coral banks is described, expressed as mounds lined up in along-slope-trending ridges. In this paper, very high-resolution single-channel seismic profiles are used to evaluate to what extent the bottom currents influenced the deposition of the sediments surrounding the mounds throughout the Late Cenozoic. Three seismostratigraphic units (P1, P2 and P3) can be identified in the Belgica mound area, separated by two margin-wide discontinuities (RD2 and RD1). Within Unit P1 (probably Early to Middle Miocene) upslope-migrating sediment waves are observed, suggesting strong bottom currents were already active in the Miocene. After an early Middle Miocene erosion event, represented by reflector RD2, an acoustically transparent layer (Unit P2) of as yet unknown lithology was deposited in the studied area. A second margin-wide erosional event, marked by the Late Pliocene RD1 reflector, removed a large part of Unit P2 and has cut deeply into Unit P1. Subsequently, the Belgica mounds were constructed spectacularly fast on topographic irregularities on the RD1 paleobathymetry. The onlap within the Quaternary Unit P3, which surrounds these mounds, suggests that the mounds were already present before the deposition of P3 and were big enough to affect the intensity of the currents around them. Furthermore, the channels and the mounds are, together with the complex oceanographic regime, the key morphological elements responsible for the shaping of a contourite system in the Belgica mound area during the Quaternary. One drift body is formed by an inferred south–north-directed current, with a drift levee and associated channel located on its western side. Between this channel and the mounds, large-scale sediment waves suggest an intensified bottom current running along the foot of the steep flanks of the mounds. The Belgica mounds are embedded in another drift body. Here, an interaction of bottom and turbidity currents is suggested, creating short turbidite channels at the southern and northern flanks of the mounds. Locally, small confined drifts can be observed where Unit P3 is deposited in a narrow passage made by the paleobathymetry of RD1 and the mounds. |
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