Chapter 4

Landforms

Section 1-Landforms

• I. Forces below Earth’s SurfaceA. Geology-study of the Earth’s physical structures and the processes that have created them

B. Earth’s 4 zones 1. Core-inner and outer-2,000 miles a. inner is solid b. outer is mostly dense liquid metal, mainly

iron and nickel 2. Mantle-1800 miles-magma and rock 3. Crust-5-25 miles thick

• C. Internal Forces1. Planet Tectonics-explains how forces

within the planet create landforms 2. Continental Drift-plates move along mantle

at 1 inch per year 3. Volcanoes and Earthquakes are common

along plate boundaries 4. Earthquakes stem from tectonic forces

causing rocks within the crust to break 5. Pangaea

Mid-Atlantic Ridge

• D. Plate Movement 1. Plate move apart (spread), collide or move laterally past one another

2. Spreading takes place on ocean floor, magma works its way up, ocean ridges form

3. Spreading plate boundaries on continents are called rift valleys 4. Abyssal Plains-flat surface away from the ridges 5. Continental Shelf

• E. Plates Colliding 1. Trenches form under water from one

plate sliding underneath the other 2. Folds are places where rocks have

been compressed into bends 3. Faults are places where rock masses

have broken apart and moved away from each other.

4. Plate collisions create giant mountains

• II. Forces on Earth’s Surface

A. Weathering-breaking and decaying of rocks, caused by chemical processes and physical processes (heat, water and freezing)

B. Sediment-small particles of gravel, sand and mud

C. Erosion-movement of surface material from one location to another

D. Water, Wind and Waves cause erosion

Section 2-The HydrosphereI. Water on Earth

A. 97% salty, 2% frozen fresh, 1% usable

B. Desalination-process used to remove salt from fresh water

C. Amount of water never changes D. Hydrologic Cycle-Water Cycle...Pg. 70

E. Headwaters-tributaries-watershed (drainage basin)

F. Estuaries-form when river meets an inlet, or small arm, of the sea… fresh and saltwater mix

G. Wetlands-any landscape that is covered with water for at least part of the year.

H. Many have been drained for farming and building (Everglades)

I. Groundwater

a. Water found below ground

b. Water table-area where ground underneath is completely saturated

c. table fluctuates based on amount of rain or well usage

d. Lowering of table could lead to settling, slumping or cracking

II. Floods- Too much water and no where for it to go

Levees: man-made structures of dirt, rock and concrete

Levees are designed to protect habitat

Levees cause problems for civilians downstream

Section 3-Natural Resources

I. Soil and ForestsA. Resource-any physical material that makes up part of the Earth and that people need and value.

B. Renewable/Nonrenewable

C. Soil Horizon

D. Leaching (caused by rainwater) is the downward movement of minerals and humus in soils

E. Sustaining Soil Resources

1. Contour Plowing-plowing land across field to reduce slope and thus erosion

2. Crop Rotation and fertilizer prevents soil exhaustion

3. Irrigation works but can lead to soil salinization…salt from the water built up over time

F. Forests

1. Reduce erosion, provided habitats and resources

2. Deforestation-destruction or loss of forests

3. Reforestation-replanting of trees

II. Air and Water

A. What are major causes of air pollution?

B. Chemicals in air mix with sunlight to create smog…Los Angeles and Mexico City

C. Acid Rain - ruins lakes, trees and buildings

D. Air pollution can hurt the ozone layer

E. Water

1. Controlled by dams, canals, reservoirs and aqueducts

2. Accessed by wells tapping into aquifers (layers of rock were water is plentiful)

3. Fossil water is desert water that is underground from thousands of years ago

IV. Mineral Resources A. Minerals are solid substances that

come out of the ground B. Usage 1. Used to build, make metals, glass… 2. Mines 3. Ore is removed and substance is

removed from rock at alternate location 4. Some minerals are plentiful…others

are rare

V. Energy Resources

A. Fossil fuels-nonrenewable-coal, natural gas, petroleum

B. Created from remains of ancient plants and animals over millions of years

C. Uranium-nuclear plants don’t pollute air but produce radioactive waste

D. Fossil Fuels

1. Coal is old but effective and plentiful

2. Coal pollutes 3. Petroleum (oil) is accessed by drilling

4. Oil is used to make gasoline, diesel and heating fuel, asphalt and other fuels

5. Natural gas is odorless but given artificial smell for detection

6. Other uses

a. coal makes dyes

b. oil makes petrochemicals which include raw materials for making explosives, food additives, medicines, pesticides and plastics

VI. Alternative Energy Resources A. Hydroelectric Power-electricity produced by moving

water B. Dams hold water back, then allow it to run through

small openings which generates power…10% of U.S. energy

C. Windmills…wind turbinesD. Geothermal Energy-heat of the Earth’s interior, plants

built in places near volcanoes and hot springsE. Solar Energy-energy of the sun