Geology, geomorphology and sediments of the Solent system
Velegrakis, A. (2000). Geology, geomorphology and sediments of the Solent system, in: Collins, M. et al. (Ed.) Solent science: a review. Proceedings in Marine Science, 1: pp. 21-43
In: Collins, M.; Ansell, K. (Ed.) (2000). Solent science: a review. Proceedings in Marine Science, 1. Elsevier: Amsterdam. ISBN 0-444-50465-6. 385 pp., more
In: Proceedings in Marine Science. Elsevier: New York. ISSN 1568-2692; e-ISSN 2352-2860, more
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| Abstract |
The extensive recent research undertaken into the physical characteristics of the Solent Estuarine System cannot be presented within this short contribution. However, it appears that, since the time of the previous review of the relevant information (West, 1980; Dyer, 1980), our knowledge has increased significantly. Certain questions associated with the geology, geomorphology and sediments of the system have been answered; these are summarised below. Firstly, it appears that the nomenclature of the solid formations of the system has been standardised; their offshore outcrops have been now mapped more accurately. Secondly, our knowledge on the geological structure of the area has been advanced significantly, particularly in relation to the deep structural elements and the stress regime responsible for the formation of the Purbeck - Isle of Wight Monocline. Thirdly, there is now conclusive evidence to suggest that the upper reaches of the Pleistocene Solent River had been disrupted by river capture, before the Flandrian Transgression. Moreover, the marine geophysical evidence and new information on the sea level rise curve for the area suggest that the Isle of Wight was separated from the mainland around 7,0007,500 years BP. Finally, there is now substantial information on the geochemistry of the sediments and the littoral sediment budgets and transport. Moreover, the area has been used extensively as a physical laboratory, to test innovative instrumentation and methodology related to the study of sediment transport processes. Nonetheless, it appears that certain problems remain unsolved, particularly with regard to sediment distribution and transport. The information available on the overall thickness of the unconsolidated sediments within the Solent and Southampton Water is of limited resolution. Such a limitation is likely to have detrimental effects on advancing our knowledge of the system, as it confines our ability to use advanced (hybrid) models to understand (and predict) the morphological development of the system. In addition, it appears that the hydrodynamic information available is of limited duration and spatial resolution; knowledge on the hydrodynamics of the system is based mainly upon the predictions derived from numerical models, which have been rarely validated and calibrated properly. For suspended material, in particular, one of well-recognised problems in estuarine research is related to the accurate determination of the scalar fluxes in and out of the estuaries (for a review, see Jay et al. 1997). Therefore, accurate estimations and predictions of sediment transport rates and directions are not possible, at present. In conclusion, there is limited (and, in most cases, fragmentary) information available on the thickness, internal architecture and textural characteristics of the major sediment depositional areas of the system, such as the tidal deltas and offshore banks. This limitation may have significant implications as these areas not only represent the most reliable stratigraphic records of the sedimentary environment, but also because they may constitute significant pollution 'reservoirs'. |
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