88THTH GRADE SCIENCE GRADE SCIENCECOMPARE AND CONTRAST THE COMPARE AND CONTRAST THE

DIFFERENT LANDFORMS DIFFERENT LANDFORMS CAUSED BY EARTH’S CAUSED BY EARTH’S EXTERNAL FORCES.EXTERNAL FORCES.

ESS 8.8.4ESS 8.8.4

PLAINSPLAINS

Plains are large, relatively flat areas of Plains are large, relatively flat areas of land.land.

Plains found near the ocean are called Plains found near the ocean are called coastal plains.coastal plains.

Flat, grassy areas used to grow crops or Flat, grassy areas used to grow crops or for grazing are also plains.for grazing are also plains.

Together, these 2 types of plains make up Together, these 2 types of plains make up one-half of all of the land in the united one-half of all of the land in the united

states.states.

COASTAL PLAINSCOASTAL PLAINS

Coastal plains are broad areas along the Coastal plains are broad areas along the ocean’s shore.ocean’s shore.

They are often called lowlands because of They are often called lowlands because of their low elevations.their low elevations.

The Atlantic Coastal Plain stretches along The Atlantic Coastal Plain stretches along the east coast of the United States.the east coast of the United States.

This area is characterized by low rolling This area is characterized by low rolling hills, swamps, and marshes.hills, swamps, and marshes.

Coastal PlainsCoastal Plains The Atlantic Coastal Plain isn’t The Atlantic Coastal Plain isn’t

perfectly flat.perfectly flat. It has many low hills and valleys that It has many low hills and valleys that

have been carved by rivers.have been carved by rivers. The Atlantic Coastal Plain formed The Atlantic Coastal Plain formed under water about 70 million years under water about 70 million years ago from sediments composed of ago from sediments composed of marine organisms that fell to the marine organisms that fell to the

ancient ocean floor.ancient ocean floor. When the sea level dropped, the plain When the sea level dropped, the plain

was exposed.was exposed.

Coastal PlainsCoastal Plains

GULF COASTAL PLAINGULF COASTAL PLAIN

Another example is the Gulf Another example is the Gulf Coastal plain.Coastal plain.

It includes the lowlands of the It includes the lowlands of the southern United States that southern United States that surround the Gulf of Mexico.surround the Gulf of Mexico.

Much of this plain was formed Much of this plain was formed from sediments deposited by the from sediments deposited by the

Mississippi River as it entered Mississippi River as it entered the Gulf of Mexico.the Gulf of Mexico.

Texas Gulf Texas Gulf CoastCoast

Mississippi / Mississippi / Louisiana Gulf Louisiana Gulf

PlainsPlains

Interior PlainsInterior Plains

A large portion of the interior A large portion of the interior Plains is referred to as the Great Plains is referred to as the Great

Plains.Plains. They lie between the Mississippi They lie between the Mississippi

lowlands and the Rocky lowlands and the Rocky Mountains.Mountains.

The Great Plains are flat, grassy, The Great Plains are flat, grassy, dry plains with few trees.dry plains with few trees.

Interior PlainsInterior Plains

A large portion of the center of the A large portion of the center of the United States is called the Interior United States is called the Interior

Plains.Plains. They extend from the Appalachian They extend from the Appalachian

Mountains in the east to the Rocky Mountains in the east to the Rocky Mountains in the west, to the Gulf Mountains in the west, to the Gulf

Coastal Plain in the south.Coastal Plain in the south. They include the rolling hills of the They include the rolling hills of the

Great Lakes area and the central Great Lakes area and the central lowlands around the Missouri and lowlands around the Missouri and

Mississippi rivers.Mississippi rivers.

Great PlainsGreat Plains They are also called High Plains They are also called High Plains

because of their elevation.because of their elevation. They range from 350 meters above sea They range from 350 meters above sea

level at their eastern border to 1500 level at their eastern border to 1500 meters at their western boundary.meters at their western boundary.

The Great Plains are covered with The Great Plains are covered with nearly horizontal layers of loose nearly horizontal layers of loose materials eroded from the Rocky materials eroded from the Rocky

Mountains.Mountains. Streams deposited these sediments Streams deposited these sediments

over the course of the last 28 million over the course of the last 28 million years.years.

CONSTRUCTIVE AND CONSTRUCTIVE AND DESTRUCTIVE FORCES ON DESTRUCTIVE FORCES ON

LAND FORMSLAND FORMSESS 8.8.4ESS 8.8.4

CROWLEY’S RIDGECROWLEY’S RIDGE CROWLEY’S RIDGE IS A UNIQUE CROWLEY’S RIDGE IS A UNIQUE

LANDFORM IN NORTHEAST LANDFORM IN NORTHEAST ARKANSAS, RUNNING FROM ARKANSAS, RUNNING FROM

SOUTHERN MISSOURI DOWN TO SOUTHERN MISSOURI DOWN TO AROUND HELENA, ARKANSAS.AROUND HELENA, ARKANSAS.

The land in that area is relatively flat.The land in that area is relatively flat. This ridge was formed during the This ridge was formed during the

great earthquakes of 1811-1812.great earthquakes of 1811-1812. This is the same quake, along the This is the same quake, along the

New Madrid fault, that made the New Madrid fault, that made the Mississippi River change course and Mississippi River change course and

even flow backward for a while!even flow backward for a while!

swampsswamps

Swamps are low-Swamps are low-lying areas, that lying areas, that have standing have standing water in them. water in them.

They are very They are very important areas important areas for certain types for certain types

of animals.of animals.

canyonscanyons

DeltasDeltas

A delta is a triangular deposit of A delta is a triangular deposit of sediment that forms when a stream sediment that forms when a stream or a river slows as it empties into an or a river slows as it empties into an

ocean, gulf, or lake.ocean, gulf, or lake. Eventually, the Mississippi River Eventually, the Mississippi River

reaches the Gulf of Mexico with a reaches the Gulf of Mexico with a tremendous amount of sediment.tremendous amount of sediment.

The water slows down as it hits the The water slows down as it hits the gulf and the sediment spreads out in gulf and the sediment spreads out in

a triangular shape, forming the a triangular shape, forming the Mississippi Delta.Mississippi Delta.

TOPOGRAPHIC MAPSTOPOGRAPHIC MAPS

IF YOU WANTED TOI GO HIKING, A IF YOU WANTED TOI GO HIKING, A CONIC MAP PROJECTION WOULD CONIC MAP PROJECTION WOULD GET YOU TO THE MOUNTAIN, BUT GET YOU TO THE MOUNTAIN, BUT

YOU WOULD NEED A MORE YOU WOULD NEED A MORE DETAILED MAP SHOWING THE DETAILED MAP SHOWING THE HILLS AND VALLEYS OF THAT HILLS AND VALLEYS OF THAT

SPECIFIC AREA.SPECIFIC AREA. A TOPOGRAPHIC MAP SHOWS THE A TOPOGRAPHIC MAP SHOWS THE

CHANGES IN ELEVATION OF THE CHANGES IN ELEVATION OF THE EARTH’S SURFACE.EARTH’S SURFACE.

TOPOGRAPHIC MAPSTOPOGRAPHIC MAPS

Before starting your hike up the Before starting your hike up the mountain, you would look at the mountain, you would look at the

contour lines on your contour lines on your topographic map to see the trails topographic map to see the trails

change in elevation.change in elevation. A contour line is a line on a map A contour line is a line on a map

that connects points of equal that connects points of equal elevation.elevation.

Topographic mapsTopographic maps

The difference in elevation The difference in elevation between 2 side by side contour between 2 side by side contour

lines is called the contour lines is called the contour interval.interval.

If the contour interval was 10 If the contour interval was 10 meters, then when you walked meters, then when you walked between those 2 lines on the between those 2 lines on the

trail, you would have climbed or trail, you would have climbed or descended 10 meters.descended 10 meters.

Topographic mapsTopographic maps

the closer the contour lines are the closer the contour lines are together, the steeper the slope will together, the steeper the slope will

be.be. Contour intervals can be different, Contour intervals can be different, but they will be the same distance on but they will be the same distance on

that map.that map. For example, one map may have For example, one map may have contour intervals of 5 meters, while contour intervals of 5 meters, while

another map might have contour another map might have contour intervals of 100 meters.intervals of 100 meters.

Topographic mapsTopographic maps

Some contour lines, called index Some contour lines, called index contours, are marked with their contours, are marked with their

elevation.elevation. If the contour interval is 5 If the contour interval is 5

meters, you can tell the meters, you can tell the elevation of other lines around elevation of other lines around the index contour by adding or the index contour by adding or subtracting 5 meters from the subtracting 5 meters from the

elevation indicated on the index elevation indicated on the index contour.contour.

Topographic mapsTopographic maps Here are some rules to remember Here are some rules to remember

when examining contour lines.when examining contour lines. To decide whether you are looking at To decide whether you are looking at

a hill or basin, you can read the a hill or basin, you can read the elevation numbers or look for elevation numbers or look for

“hachures”“hachures” Hachures are short lines at right Hachures are short lines at right angles to the contour line that are angles to the contour line that are

used to show depressions.used to show depressions. These lines point toward lower These lines point toward lower

elevations.elevations.

Topographic mapsTopographic maps

Contour lines never cross.Contour lines never cross. Contour lines form v’s that point Contour lines form v’s that point

upstream whenever they cross upstream whenever they cross streams.streams.

Agents of Agents of ErosionErosion

REVIEWREVIEW 1. THESE ARE THE LOWLANDS OF THE SOUTHERN UNITED STATES 1. THESE ARE THE LOWLANDS OF THE SOUTHERN UNITED STATES

THAT SURROUND THE GULF OF MEXICO.THAT SURROUND THE GULF OF MEXICO. GULF COASTAL PLAINGULF COASTAL PLAIN

2. THIS IS A TRIANGULAR DEPOSIT OF SEDIMENT THAT FORMS 2. THIS IS A TRIANGULAR DEPOSIT OF SEDIMENT THAT FORMS WHEN A STREAM OR RIVER SLOWS DOWN AND EMPTIES INTO THE WHEN A STREAM OR RIVER SLOWS DOWN AND EMPTIES INTO THE

OCEAN.OCEAN. DELTADELTA

3. THIS TYPE OF MAP SHOWS THE CHANGES IN ELEVATION OF THE 3. THIS TYPE OF MAP SHOWS THE CHANGES IN ELEVATION OF THE EARTH’S SURFACE.EARTH’S SURFACE.

TOPOGRAPHICTOPOGRAPHIC 4. SHORT LINES AT RIGHT ANGLES TO THE CONTOUR LINE THAT 4. SHORT LINES AT RIGHT ANGLES TO THE CONTOUR LINE THAT

ARE USED TO SHOW DEPRESSIONS.ARE USED TO SHOW DEPRESSIONS. HACHURESHACHURES

5. LARGE, RELATIVELY FLAT AREAS OF LAND ARE:5. LARGE, RELATIVELY FLAT AREAS OF LAND ARE: PLAINSPLAINS

6. LOW LYING AREAS THAT HAVE WATER STANDING IN THEM AND 6. LOW LYING AREAS THAT HAVE WATER STANDING IN THEM AND IS THE HOME OF VERY MANY ORGANISMS.IS THE HOME OF VERY MANY ORGANISMS.

SWAMP SWAMP

REVIEWREVIEW 7. CONTOUR LINES NEVER __________.7. CONTOUR LINES NEVER __________.

CROSSCROSS 8. THE CLOSER THE CONTOUR LINES ARE, THE ___________ THE 8. THE CLOSER THE CONTOUR LINES ARE, THE ___________ THE

SLOPE WILL BE.SLOPE WILL BE. STEEPERSTEEPER

9. THIS FLAT, GRASSY AREA LIES BETWEEN THE MISSISSIPPI 9. THIS FLAT, GRASSY AREA LIES BETWEEN THE MISSISSIPPI LOWLANDS AND THE ROCKY MOUNTAINS.LOWLANDS AND THE ROCKY MOUNTAINS.

INTERIOR PLAINSINTERIOR PLAINS 10. THIS UNIQUE LANDFORM STRETCHES FROM SOUTHERN 10. THIS UNIQUE LANDFORM STRETCHES FROM SOUTHERN

MISSOURI DOWN TO HELENA, ARKANSAS.MISSOURI DOWN TO HELENA, ARKANSAS. CROWLEY’S RIDGECROWLEY’S RIDGE

11. SEDIMENTS THAT SLOWLY INCH THEIR WAY DOWN A HILL.11. SEDIMENTS THAT SLOWLY INCH THEIR WAY DOWN A HILL. CREEPCREEP

12. LOOSE MATERIALS OR ROCK LAYERS THAT SLIP DOWN A SLOPE 12. LOOSE MATERIALS OR ROCK LAYERS THAT SLIP DOWN A SLOPE IS CALLED ________________IS CALLED ________________

SLUMPSLUMP

REVIEWREVIEW 13. THIS IS A LINE ON A MAP THAT CONNECTS POINTS OF EQUAL ELEVETION13. THIS IS A LINE ON A MAP THAT CONNECTS POINTS OF EQUAL ELEVETION

CONTOUR LINECONTOUR LINE 14. THIS STRETCHES ALONG THE EAST COAST OF THE UNITED STATES.14. THIS STRETCHES ALONG THE EAST COAST OF THE UNITED STATES.

ATLANTIC COASTAL PLAINATLANTIC COASTAL PLAIN 15. THE DIFFERENCE IN ELEVATION BETWEEN 2 SIDE BY SIDE CONTOUR 15. THE DIFFERENCE IN ELEVATION BETWEEN 2 SIDE BY SIDE CONTOUR

LINES IS CALLED THE __________.LINES IS CALLED THE __________. CONTOUR INTERVALCONTOUR INTERVAL

16. A THICK MIXTURE OF SEDIMENTS AND WATER FLOWING DOWN A SLOPE.16. A THICK MIXTURE OF SEDIMENTS AND WATER FLOWING DOWN A SLOPE. MUDFLOWMUDFLOW

17. A LARGE MOVING MASS OF ICE AND SNOW IS A _______.17. A LARGE MOVING MASS OF ICE AND SNOW IS A _______. GLACIERGLACIER

18. THE TYPE OF EROSION CAUSED BY GRAVITY IS________.18. THE TYPE OF EROSION CAUSED BY GRAVITY IS________. MASS MOVEMENTMASS MOVEMENT

19. VALLEY GLACIERS CAN MAKE A U SHAPED VALLEY OUT OF A V SHAPED 19. VALLEY GLACIERS CAN MAKE A U SHAPED VALLEY OUT OF A V SHAPED VALLEYVALLEY

TRUE TRUE

REVIEWREVIEW 20. THESE ARE SHALLOW GROOVES LEFT IN ROCK, CAUSED BY A 20. THESE ARE SHALLOW GROOVES LEFT IN ROCK, CAUSED BY A

GLACIER DRAGGING BIG ROCKS.GLACIER DRAGGING BIG ROCKS. STRIATIONSSTRIATIONS

21. THE PROCESS OF BOULDERS BEING LIFTED OUT BY A GLACIER.21. THE PROCESS OF BOULDERS BEING LIFTED OUT BY A GLACIER. PLUCKINGPLUCKING

22. WHEN WIND BLOWN SEDIMENTS STRIKE ROCKS , _____ OCCURS.22. WHEN WIND BLOWN SEDIMENTS STRIKE ROCKS , _____ OCCURS. ABRASIONABRASION

23. THESE HAPPEN WHEN LARGE BLOCKS OF ROCK BREAK LOOSE 23. THESE HAPPEN WHEN LARGE BLOCKS OF ROCK BREAK LOOSE AND START TUMBLING.AND START TUMBLING.

ROCKSLIDESROCKSLIDES 24. WIND BLOWS ACROSS LOOSE SEDIMENTS REMOVING SMALL 24. WIND BLOWS ACROSS LOOSE SEDIMENTS REMOVING SMALL

PARTICLES SUCH AS CLAY, SILT, AND SAND.PARTICLES SUCH AS CLAY, SILT, AND SAND.