Shorelines in SE Scotland from
Scottish Sea Levels
raised beaches of the Firth of Forth were first studied in detail in the
1960s by a group of geomorphologists from the University of Edinburgh led by Brian Sissons.
Over a remarkable period of activity from 1965-1972, Sissons, Smith,
Cullingford and others mapped, levelled and dated the main shoreline
fragments from west of Stirling to Fife Ness. The shoreline diagram above
was made possible by this epic effort and remains one of the clearest of its
type in the world.
The diagram shows the lateral extent of the shorelines,
together with elevation and gradient. These three elements relate directly
to the formation of the shoreline:
the lateral extent of the higher shorelines
reflects the former presence of glaciers in the Forth valley. These high
shorelines pass westwards into glacial outwash deposits.
the elevation of the shorelines reflects
post-glacial uplift in response to isostatic rebound during and after
the retreat and melt of the last ice sheet
the gradient of the shorelines reflects tilting
away from the main centre of ice loading and subsequent isostatic
rebound over the south-west Grampians
The shoreline diagram points to a complex pattern of
ice retreat, isostatic rebound and global sea level change in the
post-glacial period extending from 15 thousand years ago to the present.
highest beaches of East Fife and East Lothian developed rapidly as soon as
the ice front retreated into the Firth of Firth. These beaches
originally had storm ridges, formerly displayed north of Dunbar, but most of
these delicate landforms have been lost to ploughing or building.
uplift for the highest shorelines is the current height (up to 35 m asl) plus
the fall of
sea level from the time of formation to today (up to 60 m).
the ice front retreated west of Edinburgh
the ice front stabilised at or re-advanced to
Perth. The extent of the Main Perth Shoreline suggest that sea level
remained stable for several centuries
ice retreated west of Stirling - and glaciers
probably largely disappeared from the Scottish Highlands. This is the
period of the Windermere Interstadial, a warm period that marked the
termination of the last ice sheet
during the following
Loch Lomond Stadial (Younger
Dryas) the temperature dropped sharply. Glaciers reformed on Rannoch
Moor and flowed down the Loch Lomond basin to end moraines at Menteith.
Global sea level fell and the crust of this part of Scotland was again
depressed under the weight of ice.
at the start of the Holocene glacier ice has
disappeared from Scotland. Global sea levels were rising rapidly, faster
than crustal rebound
as global sea level rise slowed down as the last
ice sheets melted in North America and Eurasia crustal rebound began to
dominate, leading to the formation of a staircase of gently tilted
raised beaches a few metres above present sea level
Recently, Smith and others have further refined the pattern of postglacial
rebound in Scotland by using deposits from the
at ~7300 BP.