Holocene sedimentation on the North Norfolk barrier coast in relation to relative sea-level change

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Abstract

Fourteen distinct sedimentary environments have been recognised in the surface sediments of the intertidal zone of the North Norfolk coast. Nine of these can be distinguished in borehole samples on the basis of sedimentological and micro-palaeontological characteristics. They comprise: gravel; channel sand; intertidal sand; intertidal silty sand; intertidal mud and marsh creek; lower salt marsh; upper salt marsh; dune sand; and peat.

Sediment accumulations have been penetrated to a depth of −8 m OD and basal peats dated by 14C back to 8410 ± 50 years BP. An overall rate of sediment accumulation (and subsidence) of about 1 m per thousand years is indicated. There is considerable persistence of sedimentary environments in the same areas during up-building, but some erosion and roll-over of the coastal barrier system has occurred. Evidence of positive and negative sea-level tendencies are present in the record, but the main development of the tract is determined by sediment supply to the beach and marshes; positive sea-level tendencies occur at c. 6610, 5970, 4630 and 2790 BP, negative sea-level tendencies occur at 4520 to 4450 and (possibly) 3470 BP.

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