Sediment waves in the eastern equatorial Atlantic: sediment record during Late Glacial and Interglacial times.

Sarntheim, Michael and Mienert, Jürgen (1986) Sediment waves in the eastern equatorial Atlantic: sediment record during Late Glacial and Interglacial times. In: North Atlantic palaeoceanography. , ed. by Summerhayes, Colin P.. Geological Society Special Publication, 21 . Geological Society, London, pp. 119-130. DOI 10.1144/GSL.SP.1986.021.01.08.

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Abstract

Standing and migrating sediment waves along the West African continental rise (3000-4500 m water depth) are characterized by a regular spacing of wave length periods that are multiples of 280 m, and by long-term pelagic sediment composition. Interpretations of their origin must account for the following evidence: (1) The wave crests generally run parallel or oblique to the continental rise and also to prevailing (net) currents, as confirmed by SEA BEAM data; (2) Migrating waves along the West African continental margin are directed only upslope, i.e. towards the East. (3) The waves have been accreting for a long time, (>1 Ma). (4) Glacial to interglacial differences in the evolution of sediment accumulation rates on crests and troughs may indicate that the accreting regime was intermittent, and that the waves were more levelled prior to 7500 years bp due to increased deposition of siliciclastic matter in the troughs. (5) Absent patterns of grain-size sorting in the fine-grained muds contradict 'conventional' models of current-related sediment transport. A superposition of large tidal components and slow thermohaline net currents (Lonsdale 1978), secondary current processes (Unsöld, pers. comm.), or a superposition of internal waves and thermohaline currents (Kolla et al. 1980) are regarded as the most probable modes of origin.

Document Type: Book chapter
Additional Information: Das Buch ist in der GEOMAR-Bibliothek vorhanden.
Keywords: Sediment waves, eastern equatorial Atlantic, Late Glacial, Interglacial
Open Access Journal?: No
Publisher: Geological Society
Projects: Enrichment
Date Deposited: 02 Sep 2016 12:18
Last Modified: 02 Sep 2016 12:18
URI: https://oceanrep.geomar.de/id/eprint/33655

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