Publication Date:
2012-01-01
Description:
The southwestern Barents Sea has experienced profound erosion during the last ∼2.7 m.y. that has resulted in the development of a characteristic glacial morphology of the continental shelf and deposition of a several-kilometer-thick sediment fan along the western margin prograding into the deep sea. In the period from ca. 2.7 to 1.5 Ma, proglacial processes, including fluvial and glaciofluvial erosion, dominated. For this period, the total average erosion of the shelf was 170–230 m, the average erosion rate was 0.15–0.2 mm/yr, and the average sedimentation rates on the fan were 16–22 cm/k.y. Subglacial erosion affected an area of ∼575,000 km2 during the period from ca. 1.5 to 0.7 Ma. Total average erosion is estimated at 330–420 m for this interval, and the average erosion rate was 0.4–0.5 mm/yr. Average sedimentation rates were 50–64 cm/k.y. During the last ∼0.7 m.y., glacial erosion mainly has occurred beneath fast-flowing paleo–ice streams topographically confined to troughs (∼200,000 km2). The total average erosion is estimated at 440–530 m, average erosion rate is 0.6–0.8 mm/yr, and average sedimentation rate on the continental slope is 18–22 cm/k.y. The amount of erosion was mainly determined by the duration of the glaciations and the location, velocity, and basal properties of the ice streams. In total, glacial erosion of the troughs has been relatively high throughout the last ∼2.7 m.y. at ∼1000–1100 m. For the banks, erosion is inferred to have increased from ca. 2.7 Ma to a peak between 1.5 and 0.7 Ma. Subsequently, little erosion occurred in these areas, which implies a total of 500–650 m of erosion. Compared with other high-latitude areas, our rates are among the highest so far reported. This comparison also demonstrates that there have been large variations in the rate of sediment delivery to the glaciated continental margins.
Print ISSN:
0016-7606
Electronic ISSN:
1943-2674
Topics:
Geosciences
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