glacial abrasion

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The grinding away of bedrock by fragments of rock incorporated in ice. It can be achieved by bodies of subglacial sediment sliding over bedrock, or by individual clasts within ice (Glasser and Bennett (2004) PPG28, 3). Abrasion is favoured where effective basal pressures are greater than 1 MPa and where there are low sliding velocities. Landforms of glacial abrasion include striae, grooves, micro-crag and tails, bedrock gouges and cracks. Ice ceases to be an effective agent for abrasion when the weight of the ice is thick enough to bring about plastic flow.

The Boulton model (1996, J. Glaciol. 42) sees abrasion as controlled by effective normal pressure, and the Hallet model (1979, J. Glaciol. 23) argues that abrasion is highest where basal melting is greatest.

Subjects: Earth Sciences and Geography.

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