Glacial Lake Pickering: stratigraphy and chronology of a proglacial lake dammed by the North Sea Lobe of the British–Irish Ice Sheet

Abstract

We report the first chronology, using four new optically stimulated luminescence dates, on the sedimentary record of Glacial Lake Pickering, dammed by the North Sea Lobe of the British-Irish Ice Sheet during the Dimlington Stadial (24-11 ka cal BP). Dates range from 17.6 AE 1.0 to 15.8AE 0.9 ka for the sedimentation of the Sherburn Sands at East Heslerton, which were formed by multiple coalescing alluvial fans prograding into the falling water levels of the lake and fed by progressively larger volumes of debris from the Wolds. Fan formation ceased $15.8 ka, at a time when permafrost was degrading and nival-fed streams were no longer capable of supplying sediment to the fans. A further age of 10.1 AE 0.7 ka dates the reworking of coversand into the early part of the Holocene, immediately post-dating Younger Dryas periglacial structures. A 45-m lake level dates to $17.6 ka, when the North Sea Lobe was already in retreat, having moved eastward of the Wykeham Moraine; it stood further east at the Flamborough Moraine by $17.3 ka. The highest (70 m) lake level and the occupation of the Wykeham Moraine date to an earlier phase of the North Sea Lobe occupation of the Vale of Pickering. #

Diamicton from the Vale of Pickering and Tabular Hills, north-east Yorkshire: evidence for a Middle Pleistocene (MIS 8) glaciation?

“…Pickering (Evans, et al, 2016). These authors suggested that the Vale of York ice lobe extended briefly at about 18.7 ka to the south of the River Humber to reach Lindholme before retreating northwards to form the recessional Escrick and York moraines.…”

“…1915; Kendall, 1893Kendall, ,1902Gaunt, 1976Gaunt, , 1981Powell et al, 1992;Frost, 1998;Thomas, 1999;Evans et al 1995;Boston et al, 2010;Evans and Thompson, 2010;Roberts et al, 2013;Busfield et al, 2015;Bateman et al, 2015;Evans et al, 2016). In the late 19 th century the primary geological survey mapped till (or 'boulder clay' as it was then described) in the Vale of York and along the Yorkshire coast (Fox-Strangways et al, 1885, 1886FoxStrangways and Barrow, 1915).…”

“…1). The Wykeham Moraine is generally taken to mark the maximum western advance of the North Sea arm of this ice-sheet, at the eastern end of the Vale of Pickering (Penny and Rawson, 1969;Evans et al, 2016), although others have suggested a more westerly maximum ice limit to the east of Pickering (Foster, 1985). However, the deposits of the Wykeham Moraine are not tills (diamicton), but consist of glaciofluvial sand and gravel, probably deposited at the frontal lobe of the ice-sheet (Penny and Rawson, 1969;Edwards, 1978).…”

“…21 -15 ka (Clark et al, 2004 a,b;Bateman et al, 2015, fig. 10;Evans et al, 2016). Glacial meltwater emanating from the icesheet margins and from snow/ice fields on the upland areas of the North York Moors discharged southwards via deeply incised valleys such as Ryedale and the deeply incised Newtondale glacial meltwater Channel (Kendall, 1902).…”

“…Glacial meltwater emanating from the icesheet margins and from snow/ice fields on the upland areas of the North York Moors discharged southwards via deeply incised valleys such as Ryedale and the deeply incised Newtondale glacial meltwater Channel (Kendall, 1902). Lake water ponded-up between the Ampleforth and Wykeham marginal moraines ( Fig.1), and eventually found an outlet to the south via deeply incised Kirkham Gorge (Kendall, 1902;Evans et al, 2016). Glacial Lake…”