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I tasca NW. Nathan Asplund. Basic Information . Itasca County, with a population of approximately 43,000, is located in north central Minnesota. The county is the third largest in the state, approximately 3,000 square miles. There are 16 cities and 42 organized townships. - PowerPoint PPT Presentation
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Itasca NW
Nathan Asplund
Basic Information • Itasca County, with a population of approximately
43,000, is located in north central Minnesota. • The county is the third largest in the state,
approximately 3,000 square miles. • There are 16 cities and 42 organized townships. • We have 1,000 lakes and over 1,000 miles of
snowmobile and skiing trails. • Itasca County offers great outdoor recreational
opportunities, including skiing, camping, hiking, boating, hunting and fishing.
http://www.co.itasca.mn.us/
Climate and Temp • A climate is made up from the major air masses
from western United States, Canada and the Mississippi River valley results in seasonal weather with major extremes in Itasca County.
• Air masses moving north from the Mississippi River valley bring a large portion of the precipitation and humidity.
Rivers
Meandering river
Oxbow lake
Rivers cont.
A meander is formed when the moving water in a river erodes the outer banks and widens its valley
A U-shaped body of water formed when a wide meander from the main stream of a river is cut off to create a lake
How the landscapes were formedThe Wadena Lobe advanced from the north several times. Its last advance deposited the Alexandria moraine (which was later reglaciated), the Itasca moraine, and the drumlin fields spanning Otter Tail, Wadena, and Todd counties. The Rainy and Superior Lobes came out of the northeast and advanced, sometimes with and sometimes independently of the Wadena. Its last advance left a coarse-textured till of basalts, gabbro, granite, iron formation, red sandstone, slate, and greenstone strewn across the northeastern half of Minnesota and as far south as the Twin Cities. The Des Moines Lobe originated in the northwest and advanced in a southeasterly direction across Minnesota and into Iowa. Its fine-textured till consisted of limestone, shale, and granite fragments, from which developed the fine prairie (now agricultural) soils found in these areas.
Information from http://www.dnr.state.mn.us/snas/naturalhistory.html
Basic Geography of Itasca• Beach ridges• Melt water channel• Esker or esker-like ridge• Drumlin• Tunnel valley• Ice-walled lake plain• Fan
Beach ridgesA beach ridge by Little Winnibigoshish lakeIn Itasca county
Example of a beach ridge
Melt Water Channel
Drainage channel cut by melt water possibly by glaciers
Eskers
Sinuous ridge of interbedded sand, gravel,and silt; interpreted to have been deposited in an ice-walledchannel or tunnel of a glacial melt water stream. Deposited bymelt water of both the Koochiching and Rainy lobes, but drainagewas generally to the south and east within the lobes.
DrumlinOval or elongated hill believed to have been formed by the streamlined movement of glacial ice sheets across rock debris, or till
Tunnel Valley
Ice-walled lake plain
Ice-walled-lake plains form in the stagnant marginal zone of glacial Ice Sheets
Alluvial Fan
POSTGLACIAL DEPOSITS• Eolian sand• Beach sediment• Alluvium• Peat• Terrace sediment
Eolian SandEolian sand—Fine-grained sand more than 5 feet (1.5 meters)thick that forms low-lying barchans dunes and sheet-sand depositsthat display shallow depressions or blowouts. Interpreted to bewindblown sand.
Beach SedimentBeach sediment—Sand and gravelly sand in low-rising terracesalong the shores of Lake Winnibigoshish and other modern lakes.Interpreted as modern beach sediment; unit may include some ice pushsediment from windblown lake ice.
AlluviumAlluvium—Interbedded fine-grained sand, fine-grained sandy loam,and silt loam; shells, wood, and other organic debris are typicallypresent. Interpreted as the deposits of modern rivers during high-waterstages.
Peat
Peat—Organic material in various stages of decomposition; somedeposits include small bodies of open water. Interpreted asswamp deposits and deposits of freshwater lakes that have filledwith vegetation.
Terrance SedimentTerrace sediment—Sand and gravelly sand above the modernfloodplain of the Big Fork River but located lower than theglacial-lake plain. Interpreted as representing the former level ofthe floodplain of the Big Fork River. The river has incised moredeeply as the local base level has dropped over time.
Giants Range Batholiths
Anticline and Syncline
Faulting
Mylonite Zone
Found exact locations by drilling
Anticline and Syncline Cont.
Dikes and Sills
Inclined Fault
Overturned Fault
Example
Folds
Examples of folds
Works Cited• http://www.dnr.state.mn.us/snas/naturalhistory.html• http://www.co.itasca.mn.us/• Google images• http://reflections.mndigital.org/cdm4/item_viewer.php?
CISOROOT=%2Fmgs&CISOPTR=1164&DMSCALE=50.00000&DMWIDTH=800&DMHEIGHT=800&DMMODE=viewer&DMFULL=0&DMOLDSCALE=1.50000&DMX=0&DMY=0&DMTEXT=&DMTHUMB=1&REC=3&DMROTATE=0&x=112&y=50