3. NEOGENE–QUATERNARY DEPOSITIONAL HISTORY OF THE EAST GREENLAND SHELF IN THE VICINITY OF LEG 152 SHELF SITES1Holger Lykke-Andersen2 |
ABSTRACTThe seismic stratigraphic architecture of the late Neogene–Quaternary deposits on the shelf in the vicinity of Sites 914–917 is described on the basis of high-resolution reflection seismic data. The geological history of the shelf is discussed. During the late Cenozoic, a huge progradational wedge was built as a consequence of enhanced erosion due to the evolving glaciation. It is inferred that the wedge is composed mainly of glaciomarine diamictons deposited outside the grounding line at the paleo-shelf edge. The sediments and the glaciers were supplied to the shelf through the Gyldenløves Trough cut into the basement on the inner shelf. By repeated glaciations, erosion was maintained in the prolongation of Gyldenløves Trough. This erosional trough was partially filled by proglacial deposits during recession periods and possibly by subglacial deposits in periods of glacial advances. It is thought that the infill process was initiated because of relative sea level rise in the Quaternary or possibly in the Pliocene. The infilling continued in the Quaternary. A surficial transparent sheet on the outer shelf is interpreted as basal till deposited by ice covering the whole shelf in the Quaternary. The youngest till on the outer shelf is interpreted to be of Saalian age; Weichselian glaciations apparently are only represented by till deposits confined to the Gyldenløves Trough. |
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