A new multi‐stage recession model for Proglacial Lake Humber during the retreat of the last British–Irish Ice Sheet

William A Fairburn,Mark D Bateman

doi:10.1111/bor.12140

Abstract

The single most prominent lake associated with the retreat phase of the last British–Irish Ice Sheet (BIIS) was Proglacial Lake Humber. The present research elucidates a revised regional history of Proglacial Lake Humber from its maximum elevation to its demise using a combination of landscape mapping and luminescence dating. The results of mapping multiple Lake Humber strandlines are now best described by an eight‐stage recessional model. Erosional highstands of the lake can be shown to post‐date the BIIS advance that deposited the Skipsea Till at around 17 ka whereas new OSL ages show that Lake Humber was nearing its demise by 15.5±0.8 ka, indicating a possible short‐lived lake. Multiple lake level stands are attributed to the switching of lake outlets from the Lincolnshire Gap to the Humber Gap and to oscillations of the BIIS blocking the latter on more than one occasion and subsequently at a lower elevation with till. The horizontal or near‐horizontal shorelines confirm that isostatic adjustment did not occur during the demise of Lake Humber, indicating that BIIS advances in the North Sea region and Vale of York were not only dynamic but of short duration.

Highlights

The first to conceive Proglacial Lake Humber was Henry Carvill Lewis (1894: map IV and p. 62), who envisaged a great North Sea glacier blocking the mouth of the Humber where it crosses through a 4km-wide gap between the Yorkshire and Lincolnshire Wolds
The model proposed by Gaunt (1976), for the Late Devensian physiographical evolution of Lake Humber, is for a transient high-level lake at ~33 m a.s.l. resulting from glacial blockage of the Humber Gap – an event linked to the westernmost penetration of the British–Irish Ice Sheet (BIIS) up the Humber estuary (Frederick et al 2001; Evans et al 2005): the recorded level increasing slightly in elevation northwards in response to isostatic unloading
As Lake Humber is known to have been in recession, with falling lake levels, it is assumed that the majority of the imprinted shorelines are regressive in nature (cf. the model for Lake Agassiz proposed by Yang & Teller (2012)), this cannot be demonstrated from field mapping alone

Summary

Introduction

The first to conceive Proglacial Lake Humber was Henry Carvill Lewis (1894: map IV and p. 62), who envisaged a great North Sea glacier blocking the mouth of the Humber where it crosses through a 4km-wide gap between the Yorkshire and Lincolnshire Wolds. Since the recognition of the 100 Foot Strandline, mapping of Lake Humber, at its maximum extent, has been based on a shoreline of ~30 m (Straw 1979; Clark et al 2004) with outflow through the Lincoln gap (Fig. 2) to The Wash area of eastern England. Gaunt (1976) considered that the disappearance of Lake Humber occurred without leaving regressive shoreline deposits. This may have been a result of silting up (Gaunt 1981) or rapid emptying.

Results

Discussion

Conclusion