glacial breach

views updated May 08 2018

glacial breach A glacially eroded trough that cuts through a ridge and so breaches a former watershed. It is formed when the outflow of a glacier (or ice sheet) is impeded, its thickness consequently increases, and ultimately a new escape route (the breach) is exploited. This process is called ‘glacial diffluence’ when a single glacier spills out of its valley, and ‘glacial transfluence’ when several breaches are formed due to the accumulation of a large ice sheet. The many breaches through the western Highlands of Scotland are due to the accumulation of transfluent ice east of the main watershed.

glacial breach

views updated May 17 2018

glacial breach A glacially eroded trough that cuts through a ridge and so breaches a former divide. It is formed when the outflow of a glacier (or ice sheet) is impeded, so that the thickness of the glacier consequently increases, and ultimately a higher escape route (the breach) is exploited. This process is called ‘glacial diffluence’ when a single glacier spills out of its valley, and ‘glacial transfluence’ when several breaches are formed, owing to the accumulation of a large ice sheet. The many breaches through the western Highlands of Scotland were caused by the accumulation of transfluent ice east of the main watershed.