Quaternary Geomorphology

A Workshop for P.G. Candidates

December 18, 2010

Dr. Don Thieme

• Geochronology, Glacial Intervals, Isotopic Dating, etc...

• Glacial Landforms and Sedimentary Deposits

• Soil Classification and Paleosols

• Sea Level and Coastal Geomorphology

Glacial Landforms and Sedimentary Deposits

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

Alpine Glacier Profile

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 morainetill plain

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

Esker in former glacial lake, Waterford, Maine

Esker near Dahlen, North Dakota

Esker fill near Plattsburgh, New York showing “openwork” (clast-supported) gravel overlying coarse sand beds

Eskers - subglacial origin

• "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.

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)

Rivers may be fed by water from a proglacial lake through a spillway (F = Lacustrine fluvial ice-contact)

• 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

Nellie Juan Glacier and terminal moraine, Prince William Sound, Alaska. (http://pubs.usgs.gov/of/2004/1216/m/m.html)

Ohio and Missouri Rivers follow ice margins

Glacial Lakes occur north of both rivers

No Glacial Lakes south of these rivers

Climbing ripples from an ice-contact delta in Rhode IslandVarves in a Swedish glacial lake

• The "channeled scablands" in Washington state were formed by outburst floods from proglacial Lake Missoula

Carbondale

Shelbyville

Devensian glaciation (OIS- 2, 4)

followed by the Flandrian transgression (OIS-1)

in England, Wales, and Scotland