Palaeoenvironmental interpretation of an ice-contact glacial lake succession: an example from the late Devensian of southwest Wales, UK

TY - JOUR

T1 - Palaeoenvironmental interpretation of an ice-contact glacial lake succession: an example from the late Devensian of southwest Wales, UK

AU - Etienne, James L.

AU - Jansson, Krister N.

AU - Glasser, Neil F.

AU - Hambrey, Michael J.

AU - Davies, Jeremy Robin

AU - Waters, Richard A.

AU - Maltman, A. J.

AU - Wilby, Philip R.

N1 - Hambrey, M.J., Etienne, J.L., Jansson, K.N., Glasser, N.F., Davies, J.R., Waters, R.A., Maltman, A.J., Wilby, P.R., (2006) Palaeoenvironmental interpretation of an ice-contact glacial lake succession: an example from the late Devensian of southwest Wales, UK, Quaternary Science Reviews 25 (7-8), pp. 739–762

PY - 2006/4

Y1 - 2006/4

N2 - During the late Devensian (late Weichselian) glaciation, a number of large proglacial lakes developed in dammed river valleys along the southwest coast of Wales, U.K. This paper presents sedimentological data, together with a Digital Terrain Model, to establish the sedimentation history, dynamics and evolution of the largest lake, glacial Llyn (Lake) Teifi. Buried valley-fill sequences within the margins of the former lake basin reveal a thick succession of glaciolacustrine muds which coarsen upward into, or are locally abruptly overlain by, proximal deltaic, subglacial and glaciofluvial deposits. Sediment delivery pathways represented in the lacustrine succession include gravity flows, suspension settling, deltaic aggradation and iceberg rafting, the latter indicating icecontact conditions. The lacustrine muds are variably deformed, with a range of syn- and post-depositional structures, some of which indicate subglacial deformation associated with overriding of the lacustrine succession. Syn-depositional structures indicate high sedimentation rates, which may explain an absence of bioturbation structures. The overall coarsening-upward succession and cap of subglacial and/or glaciofluvial deposits support recent theories suggesting that glacial Llyn Teifi formed during glacial advance. There is no evidence to support glaciomarine conditions of sedimentation in this area of the Irish Sea basin.

AB - During the late Devensian (late Weichselian) glaciation, a number of large proglacial lakes developed in dammed river valleys along the southwest coast of Wales, U.K. This paper presents sedimentological data, together with a Digital Terrain Model, to establish the sedimentation history, dynamics and evolution of the largest lake, glacial Llyn (Lake) Teifi. Buried valley-fill sequences within the margins of the former lake basin reveal a thick succession of glaciolacustrine muds which coarsen upward into, or are locally abruptly overlain by, proximal deltaic, subglacial and glaciofluvial deposits. Sediment delivery pathways represented in the lacustrine succession include gravity flows, suspension settling, deltaic aggradation and iceberg rafting, the latter indicating icecontact conditions. The lacustrine muds are variably deformed, with a range of syn- and post-depositional structures, some of which indicate subglacial deformation associated with overriding of the lacustrine succession. Syn-depositional structures indicate high sedimentation rates, which may explain an absence of bioturbation structures. The overall coarsening-upward succession and cap of subglacial and/or glaciofluvial deposits support recent theories suggesting that glacial Llyn Teifi formed during glacial advance. There is no evidence to support glaciomarine conditions of sedimentation in this area of the Irish Sea basin.

U2 - 10.1016/j.quascirev.2005.03.019

DO - 10.1016/j.quascirev.2005.03.019

M3 - Article

VL - 25

SP - 739

JO - Quaternary Science Reviews

JF - Quaternary Science Reviews

SN - 0277-3791

IS - 7-8

ER -