Sedimentaire strukturen in de "Southern Bight" van de Noordzee
Aalders, H.W. (1972). Sedimentaire strukturen in de "Southern Bight" van de Noordzee. NIOZ-rapport, 1972(17). Nederlands Insituut voor Onderzoek der Zee: Texel. 12, 12 pp.
Deel van: NIOZ-rapport. Netherlands Institute for Sea Research (NIOZ): Den Burg. ISSN 0923-3210, meer
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| Abstract |
In the Southern Bight of the North Sea 21 boxcores have been taken. In the central part of the Southern Bight, directional bimodal, mainly small-scale crossbedding, with some troughshaped sets are found. In 2 boxcores, large scale crossbedding is found. The grainsize, the sedimentary structures, and the calculated current velocities at one meter above the bed during spring tide, point to (recent) sedimentation by migration of small scale ripple trains under the normal flow regime in the Southern Bight. Boxcores from the sand wave field show no signs of a different sedimentation regime. Nor the sedimentary structures in boxcores from the depression west of the Brown Bank do. A slight dominance in the northern direction of the orientation of the cross bedding supports the calculated net sand transport to the north (McCAVE, 1971a). Off the coast of Holland, sedimentary structures and their orientation point to wave influence in sedimentation at 18 m depth. Sand, gravel and mud has been found close together off Lowestoft (East Anglia). The gravel consists for over more than 80% of flint, and shows no signs sedimentary structures. The gravel has recently been replaced. The mud consists of layers of sand, alternating with horizontally laminated clay. The recent deposition of clay is probably the result of a high concentration of suspended sediment during considerable time, coupled with negligible wave activity (McCAVE, 1971b). |
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