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Quaternary Geomorphology A Workshop for P.G. Candidates December 18, 2010 Dr. Don Thieme
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Geochronology, Glacial Intervals, Isotopic Dating, etc... Glacial Landforms and Sedimentary Deposits Soil Classification and Paleosols Sea Level and Coastal Geomorphology
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Glacial Landforms and Sedimentary Deposits
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Glaciers glaciers form where snowfall is high and temperatures low high altitudes (alpine glaciers) high latitudes ( ice sheets) accumulation – addition of snow to a glacier snowfall rain ablation – the loss of snow and ice from a glacier melting sublimation calving
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Alpine Glacier Profile
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end moraine Inputs (zone of accumulation) vs. Outputs (zone of ablation) Three Possible Situations: Inputs > outputs - advancing glacier Inputs = outputs – stationary glacier Inputs < outputs – retreating glacier end moraine till plain
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Ogives icefield near Juno, AK Ogives “ waves ” or “ bands ” of ice annual features useful for calculating velocity of glacial advance and retreat also indicate glacier base and margins
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Esker in former glacial lake, Waterford, Maine
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Esker near Dahlen, North Dakota
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Esker fill near Plattsburgh, New York showing “openwork” (clast-supported) gravel overlying coarse sand beds Eskers - subglacial origin
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"morphosequence" of glacial and proglacial landforms all deposits laid down as the ice stood at a mappable location on the Earth's surface. proglacial deposits are supplied by the "dirt machine" that occurs where live ice rides up over stagnant ice.
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Proglacial rivers or lakes may begin directly in front of the stagnant ice: (A = fluvial ice-contact; C = lacustrine ice- contact). Proglacial lakes may be fed by meltwater rivers (D = Fluvial lacustrine ice-contact)
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Rivers may be fed by water from a proglacial lake through a spillway (F = Lacustrine fluvial ice-contact)
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glaciers dam pre-existing rivers glaciers depress the land surface, forming new lake basins glaciers produce moderate to large volumes of water during spring thaw continental glaciers produced particularly large volumes of water when they melted back during the late Pleistocene
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Nellie Juan Glacier and terminal moraine, Prince William Sound, Alaska. (http://pubs.usgs.gov/of/2004/1216/m/m.html)http://pubs.usgs.gov/of/2004/1216/m/m.html
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Ohio and Missouri Rivers follow ice margins Glacial Lakes occur north of both rivers No Glacial Lakes south of these rivers
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Climbing ripples from an ice- contact delta in Rhode Island Varves in a Swedish glacial lake
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The "channeled scablands" in Washington state were formed by outburst floods from proglacial Lake Missoula
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Carbondale Shelbyville
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Devensian glaciation (OIS- 2, 4) followed by the Flandrian transgression (OIS-1) in England, Wales, and Scotland
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