Interglacial marine deposits and strandlines of the Somerset Levels

• Main Author: Hughes, C. E.
• Published: Aberystwyth University 1980
• Subjects: 551.4
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527620

This thesis focus es on marine interglacial sediments known as the Burtle Beds from the Somerset Levels of South-west England. Particular attention is paid to the palaeomorphology and palaeoecology of the southern arm of the Levels, known today as the Parrett Valley. The Burtle Beds are shown to be estuarine marine nearshore and intertidal sediments of interglacial age. Sedimentological and palaeoecological evidence supportsa, view that these sediments were deposited in an estuarine situation exhibiting variable salinity and tidal conditions. "--ý"- A consideration of the present ecological tolerances of estuarine faunas and floras, suggests MHWS tide levels in the region of 14-15m OD in the mid-estuarine regions but rising to c. 18. Om OD in the headward regions. The interglacial marine strandline deposits of the South-west have been reappraised and cursorily assigned to specific locations within the tidal spectrum at the time of deposition. The notion of dual or multiple "Ipswichian" (Last interglacial) sea level peaks is re-examined in the light of tidal amplitudes in the Bristol Channel. It is suggested that the evidence of the marine deposits in the Somerset Levels is consistent with a single sea-level peak of c. + 6. Om (during sub-stage 5e), amplified by tidal enhancement in the narrowing, shallowing Bristol Channel to leave storm beach deposits at heights up to 18m OD in the headward regions.