The last glaciers (Loch Lomond Advance) in Snowdonia, N. Wales

Geological Journal - Tập 17 Số 2 - Trang 111-133 - 1982
John Gray1
1Department of Geography, Queen Mary College, University of London, Mile End Road, London, E1 4NS, U.K.

Tóm tắt

AbstractEvidence for 35 former cwm glaciers has been mapped in Snowdonia, N. Wales. Glacial limits are based on end moraines, boulder and drift limits, and the down‐valley extent of hummocky moraine. Protalus ramparts indicate that at least 16 semi‐permanent snow beds down to altitudes of 150 m also existed. Radiocarbon dates and pollen stratigraphy indicate that the glaciers and snow beds belong to the Loch Lomond (Younger Dryas) Stadial. The existence of a large number of ‘Older Series Moraines’ is questionned. Glacier reconstruction and contouring allows calculation of fan line altitudes, and trend surface analysis indicates that they rise from 450 m in the southwest to 700 m in the northeast. It is inferred that mean July temperature at sea‐level was around 8·5°C. Two differences between north and south Britain are recognized. Firstly in Snowdonia, as in the Lake District and Southern Uplands, the dominance of southerly air streams appears less than in the Scottish Highlands. Secondly, whereas in the Scottish Highlands, the glaciers appear to have stagnated in situ following initial active retreat, some of those farther south were active during much of the time their margins retreated.

Từ khóa


Tài liệu tham khảo

Ballantyne C. K, 1980, The Loch Lomond Advance on the Island of Rhum. Scott, J. Geol., 16, 1

10.1130/0016-7606(1970)81[1273:ODWTSO]2.0.CO;2

Colhoun E. A, 1980, The cirque moraines at Lough Nahanagan, County Wicklow, Ireland, Proc. R. Irish Acad., 80, 25

10.1098/rstb.1977.0112

Conrish R., 1981, The Loch Lomond Advance in the west‐central Southern Uplands of Scotland, Proc. Geol. Ass., 92, 105, 10.1016/S0016-7878(81)80011-9

10.1111/j.1469-8137.1972.tb02002.x

Darwin C., 1842, Notes on the effects produced by the ancient glaciers of Caernarvonshire, and on the boulders transported by floating ice, Philos. Mag., 21, 180

10.1144/GSL.JGS.1909.065.01-04.21

10.1017/S0016756800181713

10.1017/S0016756800195214

Ellis‐Graflydd I. D., 1977, Late Devensian glaciation in the Upper Usk basin, Cambria, 4, 46

Embleton C., 1975, Glacial Geomorphology

Eacritt E. A., 1971, Plumbing the depths of Idwal's moraines, Geogr. Mag., 44, 52

10.1111/j.1469-8137.1977.tb01560.x

10.1139/e79-121

Godwin H., 1955, Vegetational history at Cwm Idwal: a Welsh plant refuge, Svensk. Botanisk. Tidskrift, 49, 35

Gray J. M, 1972, The Loch Lomond Readvance moraines of Mull and Menteith. Scott, J. Geol., 8, 95

Ball D. F., 1977, Studies in the Scottish Lateglacial Environment, 163

Ince J.1961.Pollen analysis and radiocarbon dating of Lateglacial and early Flandrian deposits in Snowdonia N. Wales. Unpublished Ph.D. thesis. City of London Polytechnic.

John T. J., 1902, A bathymetrical and geological study of the lakes of Snowdonia and eastern Caernarvonshire, Trans. R. Soc. Edinb., 40, 419

Kendall P. F., 1893, On a moraine‐like mound near Snowdon, Glacialist Mag., 1, 68

Kisdson E., 1890, Trans. Notts. Sat Soc., 14

10.1002/gj.3350020207

10.1017/S001675680014141X

Rassay A. C., 1860, The Old Glaciers of Switzerland and North Wales.

10.1098/rstb.1977.0102

10.1016/0031-0182(81)90097-3

10.1017/S0022143000024394

Ball D. F., 1962, Late‐glacial deposits at Llyn Dwythwch and Nant Fírancon, Caernarvonshire, Proc. R. Soc., 244, 459

10.1080/00369227208736225

Ball D. F., 1974, A late‐glacial ice cap in the central Grampians, Scotland, Trans. Inst Br. Geogr., 62, 95

Ball D. F., 1976, The Geomorphology of the British Isles: Scotland.

Ball D. F., 1977, Studies in the Scottish Lateglacial Environment, 45

10.1144/sjg13010023

10.1080/00369227908736423

Ball D. F., 1979, Palaeoclimatic inferences from former glaciers in Scotland and the Lake District, Nature, 278, 518, 10.1038/278518a0

10.1038/280199a0

Ball D. F., 1980, The Loch Lomond Advance in the Lake District, northern England, Trans. R. Soc. Edinb: Earth Sci., 71, 13, 10.1017/S0263593300013468

Ball D. F., 1980, Studies in the Lateglacial of North‐West Europe, 31

Ball D. F., 1972, The last glaciers in the Lochnager area, Aberdeenshire. Scott, J. Geol., 8, 85

Ball D. F., 1976, Climatic inferences from former glaciers in the South‐East Grampian Highlands, Scotland, J. Glaciol., 17, 325, 10.3189/S0022143000013617

Thompson K. S. R.1972.The last glaciers in western Perthshire.Unpublished Ph.D. Thesis University of Edinburgh.

Uawin D. J.1970.Some aspects of the glacial geomorphology of Snowdonia North Wales. Unpublished M. Phil thesis. University of London.

Ball D. F., 1973, The distribution and orientation of conies in northern Snowdonia, Wales, Trans. Inst Br. Geogr., 58, 85

Ball D. F., 1975, The nature and origin of the corrie moraines of Snowdonia, Cambria, 2, 20

Ball D. F., 1977, Wales and the Cheshire‐Shropshire Lowland, 48

Walker R.1977.The Late‐Quaternary history of the diatom flora of high mountain tarns in N. Wales.Unpublished Ph.D. Thesis Liverpool Polytechnic.

10.1111/j.1469-8137.1978.tb01654.x

Thông tin
Thông tin xuất bản

Geological Journal

Tập 17 Số 2

111-133

Thông tin tác giả