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Download Illinois Geology and Climate - Powerpoint for April 11.
Transcript
Geology of Illinois Garden of the Gods – Shawnee Hills Bedrock and Basement Rock • Basement rock - the igneous and metamorphic rocks that compose the Earth's crust below the oldest sedimentary rocks • Bedrock - first solid rock strata encountered at the surface or below soil deposits Apple River, Near Galena Mississippi Palisades, Savannah, IL Rockford, Illinois Starved Rock State Park Giant City State Park Major cycles of variation in temperature Causes of 100,000 year cycle in temperature variation Earth during Wisconsinian glaciation Wisconsinian Glaciation Wisconsinian vs. Today Glacial Landforms – North America Glacial Moraines Glacial Deposits • Glacial till - unsorted, unstratified mixture of clay, silt, sand and cobbles deposited directly by glaciers - glaciers pick up tremendous amounts of sediment and rock • Glacial drift - the general term for sediment and rock left by glaciers is drift - deposits of clay, silt, sand, gravel and boulders left by glaciers or their meltwater streams Exposed glacial till Glacial Drift at Fox River Stone Company – St. Charles, IL – 100 feet of drift over bedrock Illinois River Valley Glacial Moraines Moraines in Illinois – Wisconsinian Glacier Moraine View State Park Moraine on Illinois Hwy 4 Recent Geology - Illinois Endangered Wetland Regions and Endangered Species Prairie pothole ponds and marshes Prairie pothole ponds and marshes Drainage Ditches Installing drainage tiles Original style drainage tiles Tiles draining into drainage ditch Areas where drainage tiles are used Glacial erratic in Alberta Glacial Erratic – New York Exposed Loess Deposit Glacial Landscape – Cross-section Glacial Landscape – McHenry County, IL Illinois Climate Mean Monthly Temperatures – Urbana, Illinois – 1961-2000 Pollen Data – from Nova Scotia Tree Distributions – Post-Glacial Cyclical climate and ecological change at Billy’s Lake, MN • 10,000 to 8020 BP - jack pine, red pine forest with some oaks • 8020 to 3400 BP - grassy prairies (with sage 5000 to 4000 BP) and with oak after that • 3400 to 1000 BP - deciduous forest - oakgrass to oak-birch to birch-hornbeam • 1000 BP to present - pine forest - birchwhite pine
