Open AccessD ynamic D evensian ice flow in NE E ngland: a sedimentological reconstruction
Author(s) -
Davies Bethan J.,
Roberts David H.,
Bridgland David R.,
Cofaigh Colm Ó
Publication year - 2012
Publication title -
boreas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 74
eISSN - 1502-3885
pISSN - 0300-9483
DOI - 10.1111/j.1502-3885.2011.00237.x
Subject(s) - outwash plain , geology , ice shelf , glacier , ice stream , geomorphology , sedimentary depositional environment , glacial period , deposition (geology) , geochemistry , sea ice , oceanography , cryosphere , sediment , structural basin
This study reconstructs the depositional environments that accompanied both ice advance and ice retreat of the last B ritish– I rish I ce S heet in NE E ngland during the L ast G lacial M aximum, and proposes three regional ice‐flow phases. The L ate D evensian (29–22 cal. ka BP ) T yne G ap I ce S tream initially deposited the B lackhall T ill F ormation during shelf‐edge glaciation ( P hase I ). This subglacial traction till comprises several related facies, including stratified and laminated diamictons, tectonites, and sand and gravel beds deposited both in subglacial canals and in proglacial streams. Eventually, stagnation of the T yne G ap I ce S tream led to ice‐marginal sedimentation in C ounty D urham ( P hase II ). During the D imlington S tadial (21 cal. ka BP ), the N orth S ea L obe advanced towards the coastline of N N orfolk. This resulted initially in sandur deposition (widespread, tabular sand and gravel; the P eterlee S and and G ravel F ormation; P hase II ) and ultimately in deposition of the H orden T ill F ormation ( P hase III ), a massive subglacial till. As the N orth S ea L obe overrode previous formations, it thrusted and stacked sediments in C ounty D urham, and dammed proglacial lakes between the east‐coast ice, the P ennine uplands and the remaining P ennine ice. The N orth S ea L obe retreated after H einrich E vent 1 (16 ka). This study highlights the complexity of ice flow during the L ate D evensian glaciation of NE E ngland, with changing environmental and oceanic conditions forcing a mobile and sensitive ice sheet.