24
J.S.Smith
Shoreline Regularisation
Later in response to the warming world climate, sea levels rose rapidly, and the coastal
zone was inundated by a major marine transgression (the Flandrian transgression)
which caused a landwards migration of the shoreline, leading to the burial of peats and
their capping with marine deposits. The highest point of the post-glacial transgression
is marked by the well-marked sea cliff at about 6 m. O.D. which can be traced almost
continuously from Strathbeg in the north to Aberdeen City in the south. It also formed
the well-defined inland margin of the Moray strandplains as at the Binn Hill. Final
land emergence caused a second seaward shoreline displacement, during which vast
quantities of sands and gravels were made available for shoreline regularisation.
Successive shingle bars hinged on till or isolated bedrock headlands mark the progress
of this final period of shoreline displacement. In areas where substantial coastal
embayments existed, as in the Moray coast or the east coast of Aberdeenshire,
regularisation involved the construction of the wide strandplains on which blown sand
accumulated. On occasion blown sand deposits extended landward of the marine limit
forming a veneer on till and fluvioglacial landforms. In response to dominant wind
and wave activity, shingle spits were built, deflecting the Ythan to the south on the east
coast, and the Spey and Lossie to the west on the north coast. The smooth arcuate
nature of the coastal plain between Aberdeen and Collieston, between Buchanhaven
and Inzie Head, and between Spey Bay and Lossiemouth represent a final shoreline
equilibrium form achieved through the recycling of sediment by wave and current.
West of Burghead, active shoreline progradation continues through the building
westwards of spits and bars. Much of the material is derived from re-cycling of
existing forelands as in Burghead Bay, resulting in problems of coastal edge erosion,
as waves and currents sweep the material westwards into the Inner Moray Firth.
In the case of the smaller bayhead beaches, the processes of change are less
dramatic, as a balance appears to exist between material supplied from cliff and
offshore sources, and that lost from the beach by downcombing during heavy swell. On
the Banffshire coast, where each unit is separated from its neighbour by cliff coasts and
stretches of deep water, each beach unit functions separately, but in the Inner Moray
Firth, where large units are linked in arcuate coastal sweeps, coastal edge erosion is
associated with deflation of the exposed dune faces. Backshore erosion at Burghhead
Bay has in the past revealed exposures of the peat which formed during the shoreline
regression phase preceding the Flandrian.
The Building of Dune Systems and Human Impacts
On top of the shingle forelands where the constituent material reflects the formerly
abundant supply of fluvial and fluvial-glacial materials, sand deflated from the drying
upper beaches has accumulated as dune systems. These vary locally in their form and
complexity. The relatively simple successive foredunes of Strathbeg, St. Fergus and
Lossie form massive ridges separated by slacks. At the Sands of Forvie, and to a lesser
extent Culbin, the forms are much more complex, including parabolic dunes whose
J.S.Smith
Shoreline Regularisation
Later in response to the warming world climate, sea levels rose rapidly, and the coastal
zone was inundated by a major marine transgression (the Flandrian transgression)
which caused a landwards migration of the shoreline, leading to the burial of peats and
their capping with marine deposits. The highest point of the post-glacial transgression
is marked by the well-marked sea cliff at about 6 m. O.D. which can be traced almost
continuously from Strathbeg in the north to Aberdeen City in the south. It also formed
the well-defined inland margin of the Moray strandplains as at the Binn Hill. Final
land emergence caused a second seaward shoreline displacement, during which vast
quantities of sands and gravels were made available for shoreline regularisation.
Successive shingle bars hinged on till or isolated bedrock headlands mark the progress
of this final period of shoreline displacement. In areas where substantial coastal
embayments existed, as in the Moray coast or the east coast of Aberdeenshire,
regularisation involved the construction of the wide strandplains on which blown sand
accumulated. On occasion blown sand deposits extended landward of the marine limit
forming a veneer on till and fluvioglacial landforms. In response to dominant wind
and wave activity, shingle spits were built, deflecting the Ythan to the south on the east
coast, and the Spey and Lossie to the west on the north coast. The smooth arcuate
nature of the coastal plain between Aberdeen and Collieston, between Buchanhaven
and Inzie Head, and between Spey Bay and Lossiemouth represent a final shoreline
equilibrium form achieved through the recycling of sediment by wave and current.
West of Burghead, active shoreline progradation continues through the building
westwards of spits and bars. Much of the material is derived from re-cycling of
existing forelands as in Burghead Bay, resulting in problems of coastal edge erosion,
as waves and currents sweep the material westwards into the Inner Moray Firth.
In the case of the smaller bayhead beaches, the processes of change are less
dramatic, as a balance appears to exist between material supplied from cliff and
offshore sources, and that lost from the beach by downcombing during heavy swell. On
the Banffshire coast, where each unit is separated from its neighbour by cliff coasts and
stretches of deep water, each beach unit functions separately, but in the Inner Moray
Firth, where large units are linked in arcuate coastal sweeps, coastal edge erosion is
associated with deflation of the exposed dune faces. Backshore erosion at Burghhead
Bay has in the past revealed exposures of the peat which formed during the shoreline
regression phase preceding the Flandrian.
The Building of Dune Systems and Human Impacts
On top of the shingle forelands where the constituent material reflects the formerly
abundant supply of fluvial and fluvial-glacial materials, sand deflated from the drying
upper beaches has accumulated as dune systems. These vary locally in their form and
complexity. The relatively simple successive foredunes of Strathbeg, St. Fergus and
Lossie form massive ridges separated by slacks. At the Sands of Forvie, and to a lesser
extent Culbin, the forms are much more complex, including parabolic dunes whose