Strongly divided opinion has led to competing, apparently contradictory, views on the timing, extent, flow configuration and decay mechanism of the last British Ice Sheet. We review the existing literature and reconcile some of these differences using remarkable new seabed imagery. This bathymetric data provides unprecedented empirical evidence of confluence and subsequent separation of the last British and Fennoscandian Ice Sheets. Critically, it also allows a viable pattern of ice-sheet disintegration to be proposed for the first time. Covering the continental shelf around the northern United Kingdom, extensive echosounder data reveals striking geomorphic evidence -in the form of tunnel valleys and moraines -relating to the former British and Fennoscandian Ice Sheets. The pattern of tunnel valleys in the northern North Sea Basin and the presence of large moraines on the West Shetland Shelf, coupled with stratigraphic evidence from the Witch Ground Basin, all suggest that at its maximum extent a grounded ice sheet flowed from SE to NW across the northern North Sea Basin, terminating at the continental shelf edge. The zone of confluence between the British and much larger Fennoscandian Ice Sheets was probably across the northern Orkney Islands, with fast-flowing ice in the Fair Isle Channel focusing sediment delivery to the Rona and Foula Wedges. This period of maximum confluent glaciation (c. 30-25 ka BP) was followed by a remarkable period of large-scale ice-sheet re-organisation. We present evidence suggesting that as sealevel rose, a large marine embayment opened in the northern North Sea Basin, as far south as the Witch Ground Basin, forcing the two ice sheets to decouple rapidly along a north-south axis east of Shetland. As a result, both ice-sheets rapidly adjusted to new quasi-stable margin positions forming a second distinct set of moraines (c. 24-18 ka BP). The lobate overprinted morphology of these moraines on the mid-shelf west of Orkney and Shetland indicates that the re-organisation of the British Ice Sheet was extremely dynamic -probably dominated by a series of internally forced readvances. Critically, much of the ice in the low-lying North Sea Basin may have disintegrated catastrophically as decoupling progressed in response to rising sea levels. Final-stage deglaciation was marked by near-shore ice streaming and increasing topographic control on ice-flow direction. Punctuated retreat of the British Ice Sheet continued until c. 16 ka BP when, following the North Atlantic iceberg-discharge event (Heinrich-1), ice was situated at the present-day coastline in NW Scotland.

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Based on detailed stratigraphic investigations on a 200.6m long core (BGS borehole No. 81/26) from the Fladen Ground area (British sector), core material from the Sleipner field (Norwegian sector) and shallow seismic profiles between the core-sites, the following conclusions are drawn: (1) The North Sea was glaciated sometime during the later part of Matuyama reversed period. A complete glacial-interglacial-glacial cycle is recorded in these sediments.(2) In a period of marine sedimentation in the Middle Pleistocene, a transgression-regression cycle under boreal-arctic regime i s recorded. (3) The Fladen area has subsided between 0.9 and 0.6m/ka through the later parts of the Quaternary. (4) A major glacial event dated at between 130 and 200 ka is recorded as a thick till unit in 81/26. This till, which was deposited by ice moving from the southwest (Scotland), probably represents a period when the Scandinavian and British ice sheets coalesced in the North Sea. (5) Based on the seismic data and the stratigraphy of the Sleipner core, an ice-free, open embaymenudry land is favoured for the central North Sea during the Late Weichselian. (6) From the amino-acid data, it is shown that there has been an episodic style of sedimentation through the Quaternary. (7) Of the investigated sediments (which span the last 1 mill. year) ca 98% have been deposited under arctic to boreal-arctic conditions. Journal of Quaternary Science

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We constrain, in detail, fluctuations of two former ice caps in NW Scotland with multibeam seabed surveys, geomorphological mapping and cosmogenic 10 Be isotope analyses. We map a continuous sequence of 40 recessional moraines stretching from ~10 km offshore to the Wester Ross mountains. Surface-exposure ages from boulders on moraine ridges in Assynt and the Summer Isles region show that substantial, dynamic, ice caps existed in NW Scotland between 13-14 ka BP. We interpret this as strong evidence that large active glaciers probably survived throughout the Lateglacial Interstadial, and that during the Older Dryas period (c.14 ka BP) ice caps in NW Scotland were thicker and considerably more extensive than in the subsequent Younger Dryas Stadial. By inference, we suggest that Lateglacial ice-cap oscillations in Scotland reflect the complex interplay between changing temperature and precipitation regimes during this climatically unstable period (~15-11 ka BP). words