Late Devensian deglaciation of the Tyne Gap Palaeo-Ice Stream, northern England

Stephen Livingstone, David H. Roberts, Bethan Davies, David J A Evans, Colm Ó Cofaigh, Delia Gheorghiu

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Abstract

The deglacial history of the central sector of the last British–Irish Ice Sheet is poorly constrained, particularly along major ice-stream flow paths. The Tyne Gap Palaeo-Ice Stream (TGIS) was a major fast-flow conduit of the British–Irish Ice Sheet during the last glaciation. We reconstruct the pattern and constrain the timing of retreat of this ice stream using cosmogenic radionuclide (10 Be) dating of exposed bedrock surfaces, radiocarbon dating of lake cores and geomorphological mapping of deglacial features. Four of the five 10 Be samples produced minimum ages between 17.8 and 16.5 ka. These were supplemented by a basal radiocarbon date of 15.7 0.1 cal ka BP, in a core recovered from Talkin Tarn in the Brampton Kame Belt. Our new geochronology indicates progressive retreat of the TGIS from 18.7 to 17.1 ka, and becoming ice free before 16.4–15.7 ka. Initial retreat and decoupling of the TGIS from the North Sea Lobe is recorded by a prominent moraine 10–15km inland of the present-day coast. This constrains the damming of Glacial Lake Wear to a period before 18.7–17.1 ka in the area deglaciated by the contraction of the TGIS. We suggest that retreat of the TGIS was part of a regional collapse of ice-dispersal centres between 18 and 16 ka.
Original languageEnglish
Pages (from-to)790-804
Number of pages15
JournalJournal of Quaternary Science
Volume30
Issue number8
Early online date13 Nov 2015
DOIs
Publication statusPublished - Nov 2015

Keywords

  • British–Irish Ice Sheet; cosmogenic surface exposure dating; palaeo-ice stream; radiocarbon dating; Tyne Gap

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