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Studying glacial motion and the landforms that result requires tools from many different disciplines: physical geography, climatology, and geology are among the areas sometime grouped together and called earth science. During the Pleistocene (the last ice age), huge sheets of ice called continental glaciers advanced over much of the earth.
Franz Josef Glacier in New Zealand Features of a glacial landscape. Glacier morphology, or the form a glacier takes, is influenced by temperature, precipitation, topography, and other factors. [1] The goal of glacial morphology is to gain a better understanding of glaciated landscapes and the way they are shaped. [2]
In glacial geology, a chatter mark is a wedge-shaped mark (usually of a series of such marks) left by chipping of a bedrock surface by rock fragments carried in the base of a glacier (glacial plucking). Marks tend to be crescent-shaped and oriented at right angles to the direction of ice movement. [1] [2]
If the glacial action erodes through, a spillway (or col) forms; Horn: a sharp peak connecting multiple glacier intersections, made up of multiple arêtes. Valley step: an abrupt change in the longitudinal slope of a glacial valley; Hanging Valleys: Formed by glacial meltwater eroding the land partially, often accompanied by a waterfall. [2]
Glacial striations are usually multiple, straight, and parallel, representing the movement of the glacier using rock fragments and sand grains, embedded in the base of the glacier, as cutting tools. Large amounts of coarse gravel and boulders carried along underneath the glacier provide the abrasive power to cut trough-like glacial grooves.
Bed softness may vary in space or time, and changes dramatically from glacier to glacier. An important factor is the underlying geology; glacial speeds tend to differ more when they change bedrock than when the gradient changes. [34] Further, bed roughness can also act to slow glacial motion.
Glaciology is an interdisciplinary Earth science that integrates geophysics, geology, physical geography, geomorphology, climatology, meteorology, hydrology, biology, and ecology. The impact of glaciers on people includes the fields of human geography and anthropology.
Water from moulins may help lubricate the base of the glacier, affecting glacial motion. Given an appropriate relationship between an ice sheet and the terrain, the head of water in a moulin can provide the power and medium with which a tunnel valley may be formed.