The North East Coastline of Scotland
23
Glaciations, Deglaciation and Changing Land-Sea Relationships
The events of recurrent glaciation during the Pleistocene are much more pertinent to
the soft coast geomorphology of Northeast Scotland. The glacial history of Northeast
Scotland involved successive advances of ice both from the Moray Firth basin and
from the Deeside-Donside area. In Banffshire, the cliffs are capped by till and by the
enigmatic coastal gravels, both of which contain material of Cretaceous origin derived
from offshore. On the east coast of Aberdeenshire and Kincardine a red till derived
from Strathmore and from offlying submarine sandstone outcrops forms a prominent
capping to the sea cliffs, as at Dunnottar and Hackley Head. At several points both on
the east and north coasts, ancient elements of the preglacial coastline are plugged with
glacial till even in relatively high energy situations, testifying to the relatively slow
evolution of the inherited pre-Pleistocene bedrock coastal landforms. Examples of tillplugged sea stacks occur at Covesea and immediately south of the Bay of Nigg.
Impressive sections of superimposed coastal tills were formerly exposed at the Bay of
Nigg.
As the ice melted, large quantities of fluvioglacial materials were released into
the coastal zone, the materials being transported down preglacial river valleys as in the
case of the Spey and Findhorn, or more directly released from impressive meltwater
channels as in the Pennan-Troup Head area. The high-cliff coast near New Aberdour is
dissected by deeply incised coastal ravines which are partly of meltwater origin. In
situations where ice-fronts rested near to the present coastline, as occurred between
Aberdeen City and the Ythan, and at the Binn Hill just west of the Spey, sorted
materials were released to be later incorporated into recent coastal strandplains. Large
quantities of material travelled down the Spey and Findhorn which acted as major lateglacial spillways, as attested by the huge lateral fluvioglacial terraces of their lower
and middle valley sections.
Land-sea relationships changed as a result of the interplay of isostatic rebound
of the land and eustatic change in sea level. The result was to cause shoreline
displacement, initially rapid and latterly slowing down. Where unconsolidated
materials were subject to wave action, strandplains were formed representing the landsea relationship at that time, and subsequent land rebound raised these to form the
late-glacial shorelines which fringe the interior edges of the major coastal
embayments. On occasion, the late-glacial sea overtopped the bedrock cliffs, and
resorted the coastal gravels mentioned earlier to form beach gravels as at Portknockie.
On the east coast of Aberdeenshire, late-glacial beaches at about 30 m. O.D. can be
identified inland of the Loch of Strathbeg. Marine clays were deposited in sheltered
coastal situations as at Cruden Bay and Tipperty, often associated with a cold water
fauna. After this phase of relatively high sea level, it is evident that sea level dropped
to a level below that of the present time, resulting in river and estuarine rejuvenation.
As climate ameliorated, vegetation spread into the emerging coastal zone.
23
Glaciations, Deglaciation and Changing Land-Sea Relationships
The events of recurrent glaciation during the Pleistocene are much more pertinent to
the soft coast geomorphology of Northeast Scotland. The glacial history of Northeast
Scotland involved successive advances of ice both from the Moray Firth basin and
from the Deeside-Donside area. In Banffshire, the cliffs are capped by till and by the
enigmatic coastal gravels, both of which contain material of Cretaceous origin derived
from offshore. On the east coast of Aberdeenshire and Kincardine a red till derived
from Strathmore and from offlying submarine sandstone outcrops forms a prominent
capping to the sea cliffs, as at Dunnottar and Hackley Head. At several points both on
the east and north coasts, ancient elements of the preglacial coastline are plugged with
glacial till even in relatively high energy situations, testifying to the relatively slow
evolution of the inherited pre-Pleistocene bedrock coastal landforms. Examples of tillplugged sea stacks occur at Covesea and immediately south of the Bay of Nigg.
Impressive sections of superimposed coastal tills were formerly exposed at the Bay of
Nigg.
As the ice melted, large quantities of fluvioglacial materials were released into
the coastal zone, the materials being transported down preglacial river valleys as in the
case of the Spey and Findhorn, or more directly released from impressive meltwater
channels as in the Pennan-Troup Head area. The high-cliff coast near New Aberdour is
dissected by deeply incised coastal ravines which are partly of meltwater origin. In
situations where ice-fronts rested near to the present coastline, as occurred between
Aberdeen City and the Ythan, and at the Binn Hill just west of the Spey, sorted
materials were released to be later incorporated into recent coastal strandplains. Large
quantities of material travelled down the Spey and Findhorn which acted as major lateglacial spillways, as attested by the huge lateral fluvioglacial terraces of their lower
and middle valley sections.
Land-sea relationships changed as a result of the interplay of isostatic rebound
of the land and eustatic change in sea level. The result was to cause shoreline
displacement, initially rapid and latterly slowing down. Where unconsolidated
materials were subject to wave action, strandplains were formed representing the landsea relationship at that time, and subsequent land rebound raised these to form the
late-glacial shorelines which fringe the interior edges of the major coastal
embayments. On occasion, the late-glacial sea overtopped the bedrock cliffs, and
resorted the coastal gravels mentioned earlier to form beach gravels as at Portknockie.
On the east coast of Aberdeenshire, late-glacial beaches at about 30 m. O.D. can be
identified inland of the Loch of Strathbeg. Marine clays were deposited in sheltered
coastal situations as at Cruden Bay and Tipperty, often associated with a cold water
fauna. After this phase of relatively high sea level, it is evident that sea level dropped
to a level below that of the present time, resulting in river and estuarine rejuvenation.
As climate ameliorated, vegetation spread into the emerging coastal zone.