Oyedotun, T.D.T., Burningham, H. and French, J. R., 2013. Sediment sorting and mixing in the Camel Estuary, UK

The Camel estuary, north Cornwall, UK, is characterised by extensive intertidal flats and saltmarsh that grade into beach and sand dunes at the mouth. This and other Cornish estuaries have received considerable attention in terms of the impact of mining (principally for Sb and Sn) on sedimentation. Significant changes in sediment supplied to these systems from the local catchment occurred as a result of mining activity. The primary impacts were on supply, sedimentology and mineralogy, and the peak of these impacts occurred in the 19th century. Although pollution and chemistry indicators have been considered extensively in past studies, very little consideration has been given to the nature of estuary-coast linkages in terms of sedimentary processes. This study focuses on the sedimentological characteristics of surface and shallow intertidal sediments within the Camel estuary system. Short (15cm) sediment cores obtained from 44 sample sites were sliced at 1cm intervals and grain size analysis (using a Malvern Mastersizer 2000) was undertaken on these subsamples. A wide range of grain size parameters is examined to explore the evidence for sediment mixing and extensive sediment transport processes within the estuarine system. Results show that the sediments are dominated by medium to fine sands throughout except in the inner estuary. Sediment is moderately well sorted in the outer and mid-estuary and poorly sorted in the inner estuary. It is possible that valley shape influences sediment transport processes and inhibits the supply and active reworking of marine sands in the inner estuary.