Online Textbook 1. go to www.experiencestatehistory.com 2. Type in user name 9lastudent 3. Enter password student then click login 4. Go to program s then find Louisiana Journey click on it and choose student edition
Jan 21, 2016
Online Textbook
1. go to www.experiencestatehistory.com
2. Type in user name 9lastudent
3. Enter password student then click login
4. Go to programs then find Louisiana Journey click on it and choose student edition
Natural Land
Regions
Coastal MarshesCreated when sediment
collected at the mouths of rivers as they entered the Gulf
Low wet grassland; usually no trees
Exception: Cheniers: ridges of high ground in the marsh that run parallel to the coastline; live oak trees grow here
Saltwater, freshwater, or brackish
Floodplains
Low, flat valleys through which rivers flow
Include: Swamps, sloughs, bayous, and lakes
Vegetation: Deciduous trees (Cypress, Oak, Hickory, Pecan, Magnolia, Tupelo Gum, and Cottonwood)
sugarcane
UplandsAreas with the highest elevation
Formed when magma pressure and tectonic forces pushed the land upward
Erosion then washed away soft material, leaving the hills
Vegetation: Some deciduous trees; Dominated by coniferous trees
Coniferous: evergreen, cone-bearing trees or shrubs
Contain ancient terraces (often called hills)created by rivers
Sketch Louisiana landforms
Examples of Uplands
Largest upland area – Piney Hills
Piney Hills is the V-shaped region in the northern part of the state that includes Driskill Mountain (rises 535 feet above sea level)
Uplands: Kisatchie National Forest, Dolet Hills, Florida Parishes
Uplands
Did you know Louisiana once had Prairies?
Prairies: wide flat areas where short grasses flourish, but few trees appear
Common in southwest Louisiana
Large herds of Buffalo used to roam
Agriculture and urban development destroyed most of the natural prairies and animal life that once existed
Awesome Power of Rivers
Rivers’ sediment creates the land, and their movement shapes it
Louisiana Landforms: Floodplains, Meandering Streams, Point Bars, Natural Levees, Terraces, Deltas, Coastal Marshes, Barrier Islands, Cheniers
1. Floodplains
Floodplain: flat valley floor covered by excess water caused by heavy rains that spills over the riverbanks
Reservoir: holds excess water
2. Meandering Streams
Meandering Streams: winds its way back and forth across the floodplain in loops and curves;
Water always seeks the path of least resistance and goes around obstacles
3. Point BarsPoint Bar: formed from
sediment falling to the bottom of the river after the current slows along the inside of the meander
Oxbow lake: The meander gets larger until it creates nearly a full circle around a narrow neck of land;
the river eventually straightens itself out by cutting across the point bar.
The ends of the old meander close up to form an oxbow lake.
Oxbow lake
4. Natural levees
sediment builds along the riverbank forming strips of elevated land.
5. Terraces Terraces: elevated ridges that
formed from the old riverbeds; 50-100 feet higher than the surrounding floodplain.
Ex. Terrace: Macon Ridge: 100 miles long and 20 miles wide; Highland Road in Baton Rouge
Loess: loamy wind-blown deposits rest on terraces; behaves like clay when wet; when the thick layer of loess eroded it left the region scarred with deep gullies and high bluffs; ex. Vicksburg, Mississippi
6. Deltas
Deltas: a landform shaped like a fan or a bird’s foot where a river flows into the ocean; most famous delta is the Miss. River Delta
Bar: underwater barrier of mud that interferes with the river’s current; process continues forming bird’s-foot shape.
7. Coastal Marshes
Coastal Marshes: wet grasslands formed by river sediment deposited along the coast during floods
Brackish: fresh and saltwater mixed together
Louisiana has the largest marshland area in the U.S.
8. Barrier Islands
Barrier Islands: created after a river abandons its delta;
without fresh sediment to maintain it, the delta erodes away;
sturdy bar that formed at the river’s mouth remains.
Waves and tides deposit sand leaving a crescent shape island.
Barrier Islands Importance:
1) absorb storms;
2) protect the mainland from erosion;
3) block saltwater from entering the marsh during storms;
4) home to thousands of birds, turtles, fish, and shellfish
Before and After Katrina
9. Cheniers
Cheniers: ridges of high ground in the coastal marsh that run paralles to the coastline; composed of shell and sand; remnants of Gulf of Mexico beaches; 4 to 5 feet high and several yards wide
Example: Pecan Island and Holly Beach
Chenier is French for “place of oaks”; live oaks thrive on them
Significance of a chenier: people live on them because they do not flood; protect coastal marshes from hurricanes
Other Land Forms
Rocks:
All native rock in Louisiana is sedimentary rock; sediment compressed into rock
Louisiana rock formed between 2 and 66 million years ago
Hills
After Gulf Coastal Plain formed, geologic forces caused the land to push upward forming mountains which eroded away the forming hills
Salt Domes
Reminders of the ancient sea that once covered Louisiana
Parts of the sea dried up leaving a layer of salt and other minerals exposed
Salt was covered by sediment and now lies about 10 miles below the ground
The weight exerted so much downward pressure that in some places the salt squeezed upward like toothpaste in tall vertical columns called salt domes
Louisiana has hundreds of salt domes
They appear as wooded hills about 2 miles in diameter
Example: Five Islands: Jefferson Island, Avery Island, Weeks Island, Cote Blanche, and Belle Isle
North Louisiana, salt domes do not protrude above the earth’s surface; salt appears as a white sandy crust
Salt mining is an important industry
Mine shafts are dug into salt domes and the hard rock-like salt is mined and brought to the surface for crushing
2nd largest salt mine in world is Belle Isle
Salt Domes were once used as storage for oil
Salt Dome Locations
Salt Dome
Salt Dome
Aquifers
Aquifer: underground water reservoirAs sediment deposits slowly build up
the land, freshwater sometimes becomes trapped between two layers of sediment.
Water Table: depth in the ground at which water is located
We are now drawing out more water that is being replaced by nature.
North Louisiana is facing a problem of the falling water table of the Sparta Aquifer
Sparta Aquifer
Avery Island Salt Dome