The last British Ice Sheet: A review of the evidence utilised in the ...

22,480±300 years BP from glacimarine sediments deposited beyond the morainal banks on the shelf south of
St Kilda provides a Late Devensian age for the glacier margin. Further dates from cores in the St Kilda basin
indicate that it was deglaciated sometime after 15.2 ka BP even though glacimarine sedimentation continued
until after 13.5 ka BP (Peacock et al., 1992). The bracketing of other major landform assemblages in Scotland
has proved difficult in the absence of good chronostratigraphic control. An age bracket for the ice-marginal
landforms of the lower Dee Valley (Brown, 1993) is provided by a radiocarbon date of 12.6 ka BP on basal
peat near Braemar and a minimum age of 15,370 years BP for onshore recession of ice on the coast of
Aberdeenshire (Hall and Jarvis, 1989). The maximum age of the Ardersier Readvance in the Moray Firth
(Merritt et al., 1995) is provided by the dating of the Errol Beds that were glacitectonized during ice
overriding. Gordon and Sutherland (1993) have bracketed the Errol Beds between 17 ka and 13 ka BP.
Although an age bracket of 18 ka–13 ka BP was originally proposed for the Wester Ross Readvance by
Robinson and Ballantyne (1979), more recent speculation has placed the age of the event at 13.5 ka–13 ka BP
(Ballantyne et al., 1987; Ballantyne, 1993) at the time when the oceanic polar front migrated north of the
Scottish west coast (Ruddiman and McIntyre, 1973). A basal peat date of 12,810±155 years BP provides a
minimum age for the event (Kirk and Godwin, 1963).
2.3.3. South central Scotland
A deglacial date of 12,750±120 BP has been reported from the basal peat of a kettle hole in glacifluvial
deposits that lie between Doune Lodge and the Loch Lomond Readvance at Callander (Lowe, 1978). This
provides a minimum date for the recession of the Teith glacier from the area. The deglaciation of the
Paisley-Renfrew area of the Glasgow region is reported to have been around 12.8 ka or slightly earlier
according to radiocarbon dates on marine shells in the local Clyde Beds (Peacock, 1971; Browne et al., 1977;
Sutherland, 1986).
2.3.4. Eastern England
A variety of evidence, poorly constrained by absolute dating, has been used to propose limits of an early
Devensian glacial advance and two later readvances on Holderness (see also section 2.2.3), where the North
Sea lobe of the British Ice Sheet moved onshore. The westernmost limit of the drift on Holderness has
traditionally been used as the limit of a Devensian glaciation and an early Devensian age has been supported
for the relatively more subdued drifts west of the River Hull (e.g. Straw, 1979). As outlined above, the
readvances of Holderness and the east end of the Vale of Pickering have not been recognized by more recent
researchers, because the limits were based largely upon the nebulous criteria of moraine freshness and lacked
chronostratigraphic control. Moreover, the smoother topography of the tills in west Holderness is a result of
Holocene flooding and draping of lower altitude hummocks rather than an age difference to the slightly more
hummocky drift east of the River Hull. The westernmost limits of the North Sea ice in Holderness during the
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