GEO 322 Test 2
GEO 322 Test 2 GEOG 322
Popular in Louisiana Geography
Popular in Geography
This 10 page Study Guide was uploaded by meatwad718 on Friday September 23, 2016. The Study Guide belongs to GEOG 322 at Southeastern Louisiana University taught by Molly McGraw in Summer 2015. Since its upload, it has received 7 views. For similar materials see Louisiana Geography in Geography at Southeastern Louisiana University.
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Date Created: 09/23/16
1. Geomorphology: study of landforms Louisiana is very young vast majority consists of Cenozoic Era (6065 mya) Teritary: “age of man” (2.860 mya) Quaternary: Ice Age present scattering of older rock in Bienville and Ouachita Parish North Louisiana is older than South Louisiana Mississippi River created most of southern Louisiana sedimentary rock from fragments of existing rock existing rock is weathered, transported, and deposited transported and deposited by water, wind, ice generally deposited in horizontal beds North Louisiana: 20,000 ft. to bedrock South Louisiana: 40,000 ft. to bedrock Sediment layers dip towards Gulf of Mexico due to Mississippi River sediment deposit 2. Uplands: home to the highest elevations in the state and composed of oldest rock Characterized by layers of sedimentary rocks deposited during Mesozoic and Cenozoic Eras Uplifts— Sabine Uplift: associated with lignite (coal) mineable deposits Monroe Uplift: large oil and gas field anticlines: pushed up layer of rock; antonym of synicline erode and form ridges and hills Wolds— asymmetrical ridge with a long gentle slope on one side and steep cliff on other Kisatchie Wold: extends from Mississippi River floodplain to Rio Grande valley runs east to west of Alexandria formed from very resistant layers of the very resistant sandstone west: hills less than 400 ft.; very rugged east: hills 300 ft.; fragmented by stream erosion Chalk Hills Sicily Island Nacogdoches Wold: runs from Mississippi River to Rio Grande valley older than Kisatchie and higher elevations shaped by Sabine Uplift bisected by Red River Caddo Hills Ouachita Hills: just north of eastern end of Kisatchie Wold hills less than 300 ft. above Monroe Uplift Terrace— flat, gently sloping plains that rise above each other like steps created by Mississippi River sediment and sea level Upland complex: 150300 ft. glacial outwash; oldest belt across state from Texas to Sicily Island some in Florida Parishes characteristic soil highly oxidized (orange) sand and gravel Intermediate complex: around 100 ft. Alluvium deposit located in Florida Parishes in a narrow bend that widens westward composed of sand, silt, clay Prairie complex: 40 ft.; youngest Alluvium deposit closest to Gulf Coast composed of sand, silt, clay Plocecine Terrace Loess— structureless, uncemented, lightcolored, windborne silt deposits very fine derive from vertical cliffs victim of rapid erosion formed after last Ice Age Salt domes (diaper)— masses of salt that push up through rock layers above salt is less dense than rock and sediment; tries to push up through rock layers northwestern Louisiana, northeastern Louisiana, Gulf Coast shallow seas home to limestone, sulfur, oil, natural gas Gulf Coast Salt Dome Basin, Mississippi Salt Dome Basin, Northern Louisiana Salt Dome Basin Pimple mound— low, round, circular shaped hills about 23 ft. high, 50 ft. high often scattered or clustered on shallow slopes or flat areas, but not creek bottoms or poorlydrained areas Pleistocene Terraces geomorphic mystery west of Mississippi River 3. Lowlands: Mississippi River is most important feature of Louisiana drains 41% of continental United States 3 largest drainage basin in world (Amazon and Congo): 1,245,000 sq. mi. 2,300 miles long average gradient: 2.5/mi. source: Lake Itasca, MN major tributaries: Ohio (most water), Missouri (largest), Arkansas, Red (historic) distributary: Atchafalaya River (30% flow of river) average discharge: 470,000 cubic ft./s springs brings high water; fall contains low water Mississippi River Alluvial Plain historical floodplain formed by Mississippi River drainage basin: contains tributaries alluvial valley: “chute” delta: contains distributaries 4. Mississippi River morphology: channel: length of water joining 2 larger areas of water bank: land alongside body of water bed: bottom of river thalwag: line connecting deepest parts of channel natural levee: levee formed by natural elements backslope: slope of land behind natural levee batture: land between river and levee meander: loop, bend in river point and cut bank: created by thalwag; point usually inside meander; cut bank on outside of meander causes river movement point bar: deposit formed on inner side of meander 5. Mississippi River profiles: Gradients: increase or decrease in height of river Meander migration: may move downstream or laterally may form oxbow lakes (False River) ridge or swale topography crevasse splay crevasse: break in artificial levee overbank Deltaic Plain (Atchafalaya): 810,000 years old shifting river causing loss in wetlands Balize (“bird’s foot”) and Atchafalaya are new deltas old deltas: Plaquemines, Lafourche, St. Bernard, Teche, Cocodrie, Sale Cypremort Chenier Plain: built by Mississippi River sediment and westflowing current long, linear ridge that runs parallel to coastline French: “oak ridge” 26 m high, ¼ 1 mile wide sand/shell ridges that sit atop mud flat waves help shape plain only exist on 7% of coastline 6. Atchafalaya River: De Soto began diversion process when exploring Harold Fisk (1950s): Atchafalaya River would overtake Mississippi River by 2000 Army Corps of Engineers began regulation potable water industry transportation Morgan City being destroyed (1973 flood) 7. Flooding: Flood of 1927: 2 largest flood in Louisiana history (2011) 16.5 million acres flooded 700,000 left homeless 246 dead; 500,000 farm animals dead occurred AprilAugust Arkansas, Illinois, Kentucky, Louisiana, Missouri, Mississippi, Tennessee 120 crevasses 8. Levees: direct result of Flood of 1927 7,000 miles along Mississippi River and tributaries 30 ft. high prevents annual overbank flooding damaging wetlands 9. Flood controls: Old River Control Structure: 30% of Mississippi River flow Bonnet Carre Spillway: opened Mississippi River in New Orleans at 20 ft. Morganza Floodway: for Atchafalaya River Shreve’s cutoff 10. Wetlands: governed and regulated by Army Corps of Engineers all must have: hydrology, soil, and vegetation hydrology: water movement (permanently or periodically) wetlands are found on every continent except Antarctica make up 57% of Earth’s surface can be permanent or seasonal 11. Coastal Louisiana Wetlands: make up 41% of United States wetlands among most productive ecosystems in the world nursery for 95% of finfish and shellfish harvested 20% of estuarine dependent fisheries in United States $3.2 billion/year industry in Louisiana operate as storm buffers: 1 mile can retain up to 18 inches of flood water absorb storm surge $6 million damage per 1 mile lost Mississippi Flyaway for waterfowl flood control: temporary storage for excess runoff and as groundwater recharge areas contaminate sinks for heavy metals fillers for waste water marsh: mainly herbaceous (grasses) and some woody (shrubs) vegetation freshwater/brackish marsh and saltwater marsh swamp: herbaceous and woody vegetation freshwater 12. Wetland Loss: occurring 24 sq. mi./yr; 1 football field/38 min. combination of natural and anthropologic activities subsidence: .5 cm./yr. What is causing wetland loss? canals built for extraction of oil and gas saltwater intrusion overburden disrupts surface and subsurface hydrology (berms) natural subsidence of Mississippi River deltas (compact of sediment) rising sea levels (3.22 mm/yr.; 12 mm/yr. ) leveeing of Mississippi River prevents outbank flooding nutria faults 13. Restoring Wetlands: CWPPRA (1990): Breaux Bill Coastal Wetlands, Planning, Protection and Restoration Act 4:1 funding (federal:state): $40 million:$10 million 100 projects completed Barrier Island restoration, Marsh creation/management, Freshwater/Sediment diversion, Hydrologic restoration, Shoreline protection, Vegetation planting saltwater inversion projects Caernarvon Davis Pond ($100 million) NED: Nutria Exclusion Device Wetland Trust Fund (1986): statefunded small projects $44 million USACOE, EPA, USGS, USGSNWR Lab (Lafayette), LADNRCRD, LSU/UNO, BTENP 14. Groundwater: water that lies beneath the surface comes from precipitation that’s infiltrates soil surface (recharge) and percolates to aquifers 56% agriculture (48% irrigation, 8% aquaculture) 22% public use 17% industry 15. Aquifer: accessed through wells 13 major aquifers in Louisiana Sparta, Chicot, and Southeastern = 93% of groundwater Sparta: north Louisiana and south Arkansas supplies all or part of 16 parishes 50700 ft. thick pumping since late 1800s depleting at 2 ft./yr. 55% public use; 40% industry Chicot: southwestern Louisiana most heavily pumped in Louisiana mostly for agriculture (rice) 501,050 ft. thick, increasing southward saltwater intrusion occurring Lake Charles industry decreasing water 68% irrigation; 11% public supply; 9% industry; 8% aquaculture Southeastern: between Mississippi River and Pearl River around Lake Pontchartrain same thickness as Chicot saltwater intrusion Baton Rouge industry decreasing water 49% public use; 39% industry 16. Soils: plant growth regulate water quality and supply medium for nutrient cycle habitat for organisms (worms) engineering medium formed in place (north Louisiana) or transported (south Louisiana) soil texture: dependent on grain size (largest to smallest) sand: easy to work with; dry; fertile silt clay: difficult to grow in loam: mixture of sand, silt, clay ideal loam: 10% clay, 50% silt, 40% sand located in floodplain perfect for agriculture Tertiary Upland: oldest material in state; yellowish; grows pine trees Pleistocene Terrace: deep; not fertile; frangipane Flatwoods: intermediate/prairie terraces; poorly drained; strawberries Coastal Prairie: rice; contains clay pan Loess: Alluvial: around Mississippi River; welldrained; loamy; best for agriculture; youngest Gulf Coast Marsh: highly organic (95%); poorly drained muck: black, smelly, saturated soil peat: thick, spongey; forms coal over years
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