Here is a big new paper from the BRITICE-CHRONO project, reporting on new dates for the retreat (with occasional readvances) of the ISIS through St Georges Channel and the Celtic Sea and the "Irish Sea Glacier" which is deemed to have pressed through the Cheshire Gap and into the Midlands of England. This new terminology is a bit confusing -- but no matter. This is a very intreresting and useful paper.
J. D. Scourse, R. C. Chiverrell, R. K. Smedley, D. Small, M. J. Burke, M. Saher, K. J. J. Van Landeghem, G. A. T. Duller, C. Ó Cofaigh, M. D. Bateman, S. Benetti, S. Bradley, L. Callard, D. J. A. Evans, D. Fabel, G. T. H. Jenkins, S. McCarron, A. Medialdea, S. Moreton, X. Ou, D. Praeg, D. H. Roberts, H. M. Roberts, C. D. Clark
Jnl of Quaternary Science, 7 May 2021 (special issue article)
The BRITICE-CHRONO Project has generated a suite of recently published radiocarbon ages from deglacial sequences offshore in the Celtic and Irish seas and terrestrial cosmogenic nuclide and optically stimulated luminescence ages from adjacent onshore sites. All published data are integrated here with new geochronological data from Wales in a revised Bayesian analysis that enables reconstruction of ice retreat dynamics across the basin. Patterns and changes in the pace of deglaciation are conditioned more by topographic constraints and internal ice dynamics than by external controls. The data indicate a major but rapid and very short-lived extensive thin ice advance of the Irish Sea Ice Stream (ISIS) more than 300 km south of St George's Channel to a marine calving margin at the shelf break at 25.5 ka; this may have been preceded by extensive ice accumulation plugging the constriction of St George's Channel. The release event between 25 and 26 ka is interpreted to have stimulated fast ice streaming and diverted ice to the west in the northern Irish Sea into the main axis of the marine ISIS away from terrestrial ice terminating in the English Midlands, a process initiating ice stagnation and the formation of an extensive dead ice landscape in the Midlands.
As I have pointed out to the researchers on this team many times before, this is not how ice flows when it is grounded. Ice always flows perpendicular to the ice edge in situations unconstrained by topography, and if the ice surface was high enough (probably in excess of 350m) off the Pembrokeshire coast to maintain a flow all the way to the shelf edge at -200m, 400 km away, it must also have pushed ice much further to the east across Carmarthen Bay and up the Bristol Channel. I have discussed this with respect to Ed Lockhart's thesis, here: