(See related pages)
Below you will find key words and concepts that you should remember from this chapter.
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| ablation (wastage) | The loss of the glacial ice or snow by melting, evaporation, or breaking off into icebergs. (Also called wastage). (See page(s) 479) |
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| advancing glacier | Glacier with a positive budget, so that accumulation results in the lower edges being pushed outward and downward. (See page(s) 480) |
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| alpine glaciation | Glaciation of a mountainous area. (See page(s) 476) |
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| arête | A sharp ridge that separates adjacent glacially carved valleys. (See page(s) 489) |
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| basal sliding | Movement in which the entire glacier slides along as a single body on its base over the underlying rock. (See page(s) 480) |
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| cirque | A steep-sided, amphitheater-like hollow carved into a mountain at the head of a glacial valley. (See page(s) 488) |
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| continental glaciation | The covering of a large region of a continent by a sheet of glacial ice. (See page(s) 476) |
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| crevasse | Open fissure in a glacier. (See page(s) 483) |
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| drumlin | A long, streamlined hill made of till. (See page(s) 493) |
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| end moraine | A ridge of till piled up along the front edge of a glacier. (See page(s) 491) |
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| equilibrium line | An irregular line marking the highest level to which the winter snow cover on a glacier is lost during a melt season. (Also called snow line.) (See page(s) 480) |
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| erratic | An ice-transported boulder that does not derive from bedrock near its present site. (See page(s) 490) |
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| esker | A long, sinuous ridge of sediment deposited by glacial meltwater. (See page(s) 494) |
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| fiord | A coastal inlet that is a glacially carved valley, the base of which is submerged. (See page(s) 499) |
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| glacier | A large, long-lasting mass of ice, formed on land by the compaction and recrystallization of snow, which moves because of its own weight. (See page(s) 476) |
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| ground moraine | A blanket of till deposited by a glacier or released as glacier ice melted. (See page(s) 493) |
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| hanging valley | A smaller valley that terminates abruptly high above a main valley. (See page(s) 487) |
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| horn | A sharp peak formed where cirques cut back into a mountain on several sides. (See page(s) 489) |
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| iceberg | Block of glacier-derived ice floating in water. (See page(s) 479) |
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| ice cap | A glacier covering a relatively small area of land but not restricted to a valley. (See page(s) 478) |
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| ice sheet | A glacier covering a large area (more than 50,000 square kilometers) of land. (See page(s) 478) |
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| kettle | A depression caused by the melting of a stagnant block of ice that was surrounded by sediment. (See page(s) 494) |
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| lateral moraine | A low ridgelike pile of till along the side of a glacier. (See page(s) 491) |
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| medial moraine | A single long ridge of till on a glacier, formed by adjacent lateral moraines joining and being carried downglacier. (See page(s) 491) |
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| moraine | A body of till either being carried on a glacier or left behind after a glacier has receded. (See page(s) 491) |
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| outwash | Material deposited by debris-laden meltwater from a glacier. (See page(s) 493) |
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| plastic flow | Movement within a glacier in which the ice is not fractured. (See page(s) 483) |
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| pluvial lake | A lake formed during an earlier time of abundant rainfall. (See page(s) 498) |
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| receding glacier | A glacier with a negative budget, which causes the glacier to grow smaller as its edges melt back. (See page(s) 480) |
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| rigid zone | Upper part of a glacier in which there is no plastic flow. (See page(s) 483) |
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| rock-basin lake | A lake occupying a depression caused by glacial erosion of bedrock. (See page(s) 487) |
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| rock flour | A powder of fine fragments of rock produced by glacial abrasion. (See page(s) 486) |
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| tarns | See rock-basin lake. (See page(s) 487) |
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| terminus | The lower edge of a glacier. (See page(s) 480) |
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| theory of glacial ages | At times in the past, colder climates prevailed during which significantly more of the land surface of Earth was glaciated than at present. (See page(s) 476) |
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| till | Unsorted and unlayered rock debris carried by a glacier. (See page(s) 490) |
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| tillite | Lithified till. (See page(s) 499) |
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| truncated spur | Triangular facet where the lower end of a ridge has been eroded by glacial ice. (See page(s) 487) |
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| U-shaped valley | Characteristic cross-profile of a valley carved by glacial erosion. (See page(s) 486) |
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| valley glacier | A glacier confined to a valley. The ice flows from a higher to a lower elevation. (See page(s) 477) |
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| varve | Two thin layers of sediment, one dark and the other light in color, representing one year’s deposition in a lake. (See page(s) 494) |
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| zone of ablation | That portion of a glacier in which ice is lost. (See page(s) 480) |
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| zone of accumulation | That portion of a glacier with a perennial snow cover. (See page(s) 480) |