Verteilung und Herkunft der Sedimente in Lotkernen von der Island-Färöer-Schwelle (Nordatlantik) |
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| Authors: | Dr Kay Wohlfeil |
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| Institution: | 1. Geologisch-Pal?ontologisches Institut der Universit?t Münster, Corrensstra?e 24, 4400, Münster
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| Abstract: | The components from nine sediment cores in the region of the Iceland-Faeroe-Ridge have been analysed. In this region, characterized by very complicated hydrographical and glacial conditions, only the Arctic slope of the ridge shows comparatively clear conditions which make it possible to correlate different parts of the cores. The sedimentation on the Atlantic slope, on the contrary, seems to be less clearly differentiated due to reworking processes. The components of the sand- and pebble-fraction can be divided into an autochthonous group of basalt- and shale-pebbles, derived from the ridge itself, and an allochthonous group, transported over large distances, with quartz, crystalline rocks, sandstone, flint, and chalk as main components. Whereas the autochthonous group shows parts of the cores which can be correlated with each other based on different sedimentation rates, the distribution of allochthonous group varies so strongly that it is impossible to recognize any regularity in sedimentation. Only the flint and the chalk occur in well-defined levels and thus make possible to correlate the cores. The Iceland-Faeroe-Ridge was supplied with allochthonous components from a broad source area which was, however, homogeneous with respect to both its horizontal distribution and the time-span representend in the sediment cores. Maxima of sedimentation were subsequently blurred by reworking processes on both slopes of the ridge. During the periods of glaciation the hydrographic conditions in the North Atlantic area were completely different from those of to-day. |
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