GEOL 104 Lecture Notes - Plagioclase, Olivine, Pyroxene
17 Feb 2012
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Once the particles are frozen in the ice, they are carried till the ice melts regardless of the velocity of the ice anbd the size of the particle. Contrast this with streams and waves which deposit particles when velocity drops. Sediment deposited as a result of glacial activity is termed glacial drift. This name derives from previous theories that the material drifted in from somewhere else by water or floating ice. Glacial deposits formed directly by melting ice are termed till (unstratified drift) These form landforms like drumlins and moraines. Melting ice creates lots of water, which also transports and deposits material in sorted layers called stratified drift in features such as eskers, outwash plains, varves. Probably the most diverse sediment known by a single name. Till is dropped as ice melts and all sizes from hiue boulders to small clay particles are are deposited at once. Thus there is no size sorting or layering as in most other deposits.
