Holocene evolution of the north Norfolk coast.
The surtace and subsurtace Holocene deposits ot the
macrotidal barrier coast ot north Norfolk. between Hunstanton
and Wevbourne. have been investisated bv a coordinated studv ot
sedimentarv and foraminiteral parameters. 14 distinct
sedimentarv and vesetational areas (environmental units) are
recognisable from aerial photographs, trom which a map of their
spatial distributions has been produced.
Barriers are both prograding (Holkham Gap) and eroding
(Brancaster to Thornham) due to variations in sediment supply
and land reclamation. Present models of sediment movement
underestimate the offshore supply to the coast. In particular
the input of sediment to the Holkham Gap area from a easterly
offshore movement. Removal of fine sand to the offshore zone
occurs at channel inlets although westerly spit development of
Blakeney Point has created an embayment at Stiffkey where finer
sands accumulate. Barrier formation observed at Holkham Gap
indicates the emplacement and stabilisation of beach bars to be
a major formational process.
Sedimentarv parameter ranges delineate silt based units but
show considerable overlap between sand-based units.
Foraminiferal species assemblages delineate 4 significant
cluster groupings also separating silt based units but
amalgamating sand based units into one cluster group. The
environmental unit determination of subsurface samples was
supplemented bv stratigraphic relationship interpretations for
sand based units. 9 subsur~ace environmental units have been
separated. (i) back barrier sand and dune. (ii) peat. (iii)
inter-tidal gravel, (iv) inter-tidal sand, (v) channel sand,
(vi) inter-tidal silty sand, (vii) inter-tidal mud and marsh
creek, (viii) lower marsh and (ix) upper marsh.