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Title: Structure of some marine sedimentary bodies and their dynamic environment
Author: Britton, P. C.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1978
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Investigations into the dynamic environment and structure of some sedimentary areas in the Bristol Channel were carried out. The main area of study was the Helwick Sands, a 14 km long linear sand bank. The surface sand cover of this bank extends northwards into Carmarthen Bay, but is more varied to the south. Sand wave areas were found in association with the bank. These sedimentary features and hydrological measurements indicate the flood tidal current (eastwards flowing) to be dominant to the north of the bank and the ebb current (westwards flowing) to be dominant to the south. These current directions are sub parallel to the long axis of the bank. Near bed currents tend to be more oblique to this axis than surface ones. The area is open to attack by waves and swell travelling into the Bristol Channel from the west and southwest. It is shown that the energy input from both waves and tidal currents is sufficient to move the sea bed sediment. Investigations of the subsurface structure has shown no subsurface control on the siting and development of the bank and it is concluded that it has been hydrodynamically controlled throughout its history. Initiation of the bank started during the Flandrian Transgression, with glacial sediments being eroded by wave action and redistributed by wave and tidal current energy. The present day distribution of sediment on and around the bank is explained in terms of relative wave and unidirectional current dominance. As a part of the investigation into sediment movement, results of experiments on an intertidal sandbank in the Loughor Estuary are presented. Environmental parameters concerned with sand movement on the sea bed are considered and it is concluded that a simple approach to measurements of movement will yield as meaningful result as more sophisticated ones.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available