Meltwater Erosion Research Articles

P-forms from the Isle of Mull

Synopsis Large numbers of well preserved p-forms occur along the southern shore of Loch na Keal on the Isle of Mull. The main forms are curved and sinuous channels up to 20 m long, 3 m wide and 1.5 m deep, but bowls, sichelwannen and other forms are also present. Field measurement of the orientation of 142 channels shows that they are consistently orientated parallel to the direction of ice movement as indicated by striae, and striae are present on the floors and sides of many of the channels. The mode of origin of the p-forms is discussed and it is concluded that meltwater erosion by corrasion and/or cavitation is the most likely process with active ice later moving through them. It may be significant that the p-forms occur along the former boundary zone between mainland and Mull ice.

The Pattern of Deglaciation in Part of North Northumberland

Landforms of meltwater erosion and deposition in north Northumberland indicate that the deglaciation of the area can be resolved into four consecutive phases: (i) a period of ice-directed meltwater drainage; (ii) a period when confluent ice masses parted, resulting in the development of proglacial lakes fed by ice-directed meltwater streams; (iii) a period when meltwater and streams from ice-free ground were able to flow freely down-slope beneath stagnant ice; (iv) a period when a large lake was impounded on the margin of the dwindling Tweed ice mass and when streams in Northumberland had become more or less established in the valleys they presently occupy. THE eastern flanks of the Cheviot massif rise steeply from fringing lowlands to the plateau summit of The Cheviot at an altitude of 816 m. Composed predominantly of andesitic lavas of Old Red Sandstone age, with an emplacement granite in the centre, the massif is deeply dissected by a near-radial system of narrow, steep-sided valleys. Basins and cuestas underlain by rocks of Carboniferous age curve gently round the eastern perimeter of the massif. Rising to altitudes of 150 m, 250 m and 300 m, the cuestas are arranged crescentically and en echelon, presenting steep, west-facing escarpments of saidstone to the massif. The basins are of cementstone, and, lying mostly below ioo m, they are contained between cuestas and between cuestas and the massif. The basin and cuesta relief considerably influenced the pattern of deglaciation in north Northumberland.

Observations on a Collapsing Kame Terrace In Glacier Bay National Monument, South-Eastern Alaska

Abstract Detailed observations on a collapsing kame terrace indicate that the terrace is being reshaped by: slumping and sliding of debris into depressions, melt-water erosion on the side of the terrace, debris flows in the gullies, and stagnant-ice bursts, a phenomenon analogous to a glacier burst except in the mode of formation of the water. Temperatures in the gravel over the ice, where the gravel is about 4 m thick, indicate that the rate of melting of the upper surface of the ice due to conduction may be as high as 24 cm year−1. Highest temperatures in the gravel were recorded during periods of heavy rainfall.

Observations on a Collapsing Kame Terrace In Glacier Bay National Monument, South-Eastern Alaska

AbstractDetailed observations on a collapsing kame terrace indicate that the terrace is being reshaped by: slumping and sliding of debris into depressions, melt-water erosion on the side of the terrace, debris flows in the gullies, and stagnant-ice bursts, a phenomenon analogous to a glacier burst except in the mode of formation of the water. Temperatures in the gravel over the ice, where the gravel is about 4 m thick, indicate that the rate of melting of the upper surface of the ice due to conduction may be as high as 24 cm year−1. Highest temperatures in the gravel were recorded during periods of heavy rainfall.

The deglaciation of Arfon and Southern Anglesey, and the Origin of the Menai Straits

Features of meltwater erosion and deposition associated with deglaciation in part of north-west Wales are described and analysed. The last Irish Sea Ice in this region attained a maximum of 600 feet above present sea-level, and, with a north-south slope of about twenty-five feet per mile, terminated off south-western Lleyn. This stage is correlated with the Main Würm of probably 20–30,000 years B.P. There was no subsequent advance of Welsh Ice into the region as proposed by Greenly, and a revised hypothesis is put forward for the opening of the Menai Straits, which developed during down-wasting of stagnating Irish Sea Ice.