Geometry and development of glacial continental margin depositional systems in the Bellingshausen Sea

Nitsche, F. O.; Cunningham, Alex; Larter, Robert D; Gohl, Karsten

doi:10.1016/s0025-3227(99)00074-2

Cited by 70 publications

(73 citation statements)

References 37 publications

(40 reference statements)

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“…10) reveals changes in depositional conditions and a topographically rough seafloor from the upper rise northwards into the deep-sea basin. The structure of the southern part of Depocentre C shows the characteristics of a sediment drift (profile BAS-92324) previously described in detail by Nitsche et al (2000), Cunningham et al (2002) and Scheuer et al (2006). These characteristics are very similar to those of contourite drifts identified further east on the continental rise of the western Antarctic Peninsula, which are considered to have been developed under the influence of a bottom contour current flowing eastwards along the continental slope (e.g.…”

Section: Variations Of Depositional Conditionssupporting

confidence: 63%

Bottom-current control on sedimentation in the western Bellingshausen Sea, West Antarctica

2006

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A set of single-and multi-channel seismic reflection profiles provide insights into the younger Cenozoic sedimentation history of the continental rise in the western Bellingshausen Sea, west and north of Peter I Island. This area has been strongly influenced by glacially controlled sediment supply from the continental shelf, interacting with a westward-flowing bottom current. From south to north, the seismic data show changes in the symmetry and structure of a prominent sediment depocentre. Its southernmost sector provides evidence of sediment drift whereas northwards the data show a large channellevee complex, with a western levee oriented in the opposite direction to that of the drift in the south. This pattern indicates the northward-decreasing influence of a westward-flowing bottom contour current in the study area. Topographic data suggest the morphologic ridges at Peter I Island to be the main features responsible for variable bottom-current influence, these acting as barrier to the bottom current and entrained sedimentary material. West of Peter I Island, the east-orientated Coriolis force remains effective in deflecting the suspended load of the turbidity currents towards the west, thereby promoting growth of the western channel levee. Calculated sediment accumulation rates based on seismic data reveal Depocentre C to consist of younger Cenozoic material supplied by glacial transport and modified by contour currents in the western Bellingshausen Sea. These findings demonstrate that the shape, structure and distribution of sediment mounds and estimates of sediment accumulation rates can be associated to the influence of bottom currents and their long-term evolution in response to tectonic movements, ice-sheet dynamics and deep-water formation.

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Section: Variations Of Depositional Conditionssupporting

confidence: 63%

Bottom-current control on sedimentation in the western Bellingshausen Sea, West Antarctica

2006

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“…The gentle dip of the slope in the study area is quite unusual for the West Antarctic continental margin. The upper slope may form part of a broad sediment ridge centred between 858W and 878W (Nitsche et al, 2000). Core PS2533 (71801.5VS, 85853.9VW, 588 m water depth, 1.93 m core recovery) was recovered from the ca.…”

Section: Sediment Cores and Regional Settingmentioning

confidence: 99%

The sedimentary record of the last glaciation in the western Bellingshausen Sea (West Antarctica): Implications for the interpretation of diamictons in a polar-marine setting

2005

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Upper Quaternary marine sediments recovered from the West Antarctic continental margin are characterized by a distinct lithological succession allowing the reconstruction of past environmental changes. Massive, homogenous diamictons were deposited elsewhere on the margin during the last glacial period, when grounded ice masses advanced across the shelf. Sedimentological investigations using a multi-proxy approach and examination of the margin topography suggest that during this time a deformation till and subsequently a glaciomarine till were deposited on the shelf, while glaciogenic debris flows were deposited on the slope and rise. The comparison of the clay mineral assemblages in the matrix of the diamictons with clay mineral assemblages of potential source areas reveals distinct pathways of grounded ice flow on the shelf. Lithogenic sandy muds overlying the diamictons were deposited by meltwater flows and/or marine currents on the shelf, and by turbidity currents and marine currents on the slope and rise, respectively. The sedimentation of the sandy muds denotes a deglaciation stage, when grounded ice started to retreat from the shelf, but semi-permanent sea-ice coverage still hampered biological productivity. Bioturbated, foraminifer-bearing sediments were deposited in a glaciomarine setting during the present interglacial period, when sea-ice cover was only seasonally present and a marine current related to the southern boundary of the Antarctic Circumpolar Current winnowed the seafloor on the outer shelf, slope and rise. D

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“…Small-scale instabilities are quite common: smaller slumps and slides, mass gravity £ows, turbidity currents and downslope meltwater processes through canyons have been reported by various authors (McGinnis and Hayes, 1995;McGinnis et al, 1997;Pudsey and Camerlenghi, 1998;Viseras and Maldonado, 1999;Nitsche et al, 2000;Escutia et al, 2000). However, large-scale instabilities and especially large submarine slides seem to be much more scarce than along the northern hemisphere glacial margins.…”

Section: Introductionmentioning

confidence: 97%

The Gebra Slide: a submarine slide on the Trinity Peninsula Margin, Antarctica

et al. 2003

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A large submarine slide^the Gebra Slide^has been discovered on the continental margin of Trinity Peninsula, Central Bransfield Basin, Antarctic Peninsula. The slide scar is clearly expressed in the bathymetry and is cut into the toe of the glacial-period slope-prograding strata on the lower continental slope. Seismic data give evidence of an associated debris-flow deposit embedded in the interglacial-period basin-fill strata of the basin floor. The total volume of sediment involved in the mass movement is about 20 km 3 . Indirect dating of the mass-wasting event, based on seismic^stratigraphic relationships of the slide scar and associated debris-flow deposit with underlying glacial-period slope units and the overlying interglacial-period basin-floor units, suggests that it took place at the transition between the last glacial period and the present-day interglacial. The initiation of the Gebra Slide is attributed to a combination of several factors, such as high sedimentation rates during the last glacial period, the unloading effect of a retreating ice sheet during deglaciation, pre-existing tectonic fabric and high seismicity in the area. This is the first recent submarine slide of this size identified on the glacial, continental margins of Antarctica. In morphology and general characteristics it is quite similar to the well-known large-scale submarine slides from the northern hemisphere glacial margins, although it is smaller. Its most striking characteristic is its lower-slope position (at 1500^2000 m of water depth), which remains up to now difficult to explain. ß

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Geometry and development of glacial continental margin depositional systems in the Bellingshausen Sea

Cited by 70 publications

References 37 publications

Bottom-current control on sedimentation in the western Bellingshausen Sea, West Antarctica

Bottom-current control on sedimentation in the western Bellingshausen Sea, West Antarctica

The sedimentary record of the last glaciation in the western Bellingshausen Sea (West Antarctica): Implications for the interpretation of diamictons in a polar-marine setting

The Gebra Slide: a submarine slide on the Trinity Peninsula Margin, Antarctica

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