Environmental reconstruction - Fundamentals of the Physical Environment - page 583

Table 23.2 Morphometric data of cirques in Y Glyderau range, Snowdonia

Cirque (by name)
Marchlyn Marchlyn Ceunant Cl ^ d

Graianog Perfedd Bual Coch Cywion Idwal Cneifion Bochlwyd Tryfan Gwern Y Gors

Bach Mawr Gof

Reconstructed 654 756 * 630 610 670 670 670 690 810 630 790 * 802 * 746 * 668 538

equilibrium-line
altitude (m OD)

ri tati n 8 2 0 2 1 9 0 8 3 8 0 5 0 1 3

(° from north)
Excavated

0.26 0.66 0.19 0.47 0.56 0.47 0.38 0.60 0.55 1.37 0.47 1.09 1.01 1.05 0.75

Area (km 2 )
Maximum rock-

190 190 130 200 170 170 170 220 230 420 230 230 220 180 240

wall height (m)
Elongation

0.68 1.64 1.73 1.65 1.40 1.95 1.66 1.28 1.52 1.94 2.09 1.74 1.37 1.47 1.62

Length : breadth
ratio

Notes: Mean values: equilibrium line * 7 80 m; remainder 645 m; orientation 44 o (compass 044 o ); elongation 1.58.

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Plate 23.13 The glacial cirque Cwm Coch, in the Glyderau
range above Nant Ffrancon, crowned by the summit of Foel
Goch (831 m OD), showing strong structural and subsidiary
palaeoclimate control like its neighbours. Two prominent
moraines of Late Devensian age lie below the exit to the
glacially excavated rock basin and above a fan derived from
their erosion. Wetland vegetation in the valley floor marks the
site of a former glacial lake (see also Plate 9.1 ).
Photo: Ken Addison

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Figure 23.13 Reconstruction of glacial conditions around
Snowdon, showing the probable appearance of glaciers at (a)
Late Devensian maximum (c. 18 ka BP ), (b) Loch Lomond
Advance (c.12 ka BP ) and (c) at the present time.
Source: Addison (1999)