Floodplain ManagementSESSION 3

Stream Systems on

Dynamic Earth

Glaciation & Erosion Processes

Prepared By

Donald R. Reichmuth, PhD.

Glacial & Erosion Framework

Objectives:• Glacial conditions in North America for the

last 30,000 years affect river basins and floodplains

• Rates and processes of erosion, transport, and deposition

• The production and movement of sediment by the agents/processes of erosion -- water, ice, gravity, and wind

• Case study team assignments

Glaciation & Surface Processes

• Glaciation• Alpine Glaciers• Continental Glaciers

• Geomorphology• Surface Forming Processes

– Water– Ice– Gravity– Wind

Northern Hemispheric Glacial Areas

16,000 B.P.

NOTE:

Portions Of Alaska

Are Ice Free

Pleistocene Glaciation

Note:• Alpine Glaciers

• Continental Glaciers

• Ice Marginal Rivers

• Alaska Ice Free Area

Glacial Impact Areas

Preglacial Teays Basin

Teays BasinOverrun By Ice

Channel Buried

Ohio RiverForms

Drains Basin

Western Glacial Lakes

15,000 B.P.

– Climate Much Wetter Than Present

– Large Basins Had Internal Drainage

Loess

• Wind Blown Silt

• From Glaciers• Rock Flour

• Stream Banks Stand

Vertical

When Stable

Glacial ReboundContours In Meters Uplift

Great Lakes Glacial ReboundContours – Uplift per 100 Yrs.

Sea Level Changes

16,000 Years BP -- 120 Meters Lower

6,000 Years BP – Reached Present Level

Near Future – Expected To Rise

Holocene Sea Level Changes

Primary Cause --- Glacial Melting

In The

Northern Hemisphere

Erosion In River Basins

Controlling Factors:• Chemical vs. Mechanical Weathering

– Temperature– Precipitation

• Basin Gradient• Basin Soil/Bedrock Type• Tectonic Activity

Chemical & Mechanical Weathering

Erosion Processes

Erosion Processes

Mass Movements

Class Handout

Slide Presentation Prepared By

Geomax, P.C.Dr. Donald R. Reichmuth, President

1023 W. 30th Ave.Spokane, WA 99203-1324

Phone & FAX – 509-838-6390E-mail – geomax@comcast.net