APES Unit 4 Study Guide

What are the layers of the earth?

15; Crust, mantle, outer core and inner core

What are the 3 major processes in Earths geologic cycle?

Tectonic plates, rock cycle & soil formation

Define the theory of plate tectonics

The theory that the lithosphere of the earth is divided into plates, most of which are in constant motion

Explain the movement of divergent plate boundaries and give an example

An area beneath the ocean where tectonic plates move away from each other. Ex: Seafloor spreading

Explain the movement of convergent plate boundaries and give an example

An area where plates move toward one another and collide. Ex: Subduction or continental collision

Explain the movement of transform fault boundaries and give an example

Are where two tectonic plates meet and slip and grind alongside one another. Ex: Earthquake

Define volcano

A vent in the surface of earth that emits ash, gases, or molten lava. (Occurs as a plate moves over a hot spot and heat from the mantle melts the crust)

Define earthquake

The sudden movement of earths crust caused by a release of potential energy along a geologic fault and usually causing a vibration or trembling at earths surface.

Define richter scale

A scale that measures the largest ground movement that occurs during an earthquake

How many times greater is an earthquake with a magnitude of 8 than an earthquake with a magnitude of 5?

8-5=3. Add 3 zeros. Put a 1 in front.

>1,000<

Explain the rock cycle

The continuous formation and destruction of rock on and below the surface of earth

What are the 3 types of rocks and how are they formed?

1) Igneous rock-formed from cooling magma

2) Sedimentary rock-Formed when dissolved minerals seep through sediment layers and act as a kind of glue, crystallizing and binding sediment particles together. (MAJOR SINK FOR PHOSPHORUS)

3) Metamorphic rock- Formed by great heat and/or pressure that reshapes crystals within the rock and changes its appearance and physical properties

What is a mineral

A solid chemical substance with a uniform, often crystalline, structure that forms under specific temperatures and pressures.

What is the difference between physical and chemical weathering? Give examples of each

1)Physical weathering is the mechanical breakdown of rocks and minerals. Ex: Wind or rain

2)Chemical weathering is the breakdown of rocks and minerals by chemical reactions, the dissolving of chemical elements from rock, or both. Ex: Acid rain

Explain the formation of acid rain

Sulfur is emitted into the atmosphere and reacts with oxygen to create sulfur dioxide. It then turns into sulfuric acid which lowers the pH of the rain.

Explain erosion

The removal of material from one place and its transport to another by the action of wind or water

In what ways do humans accelerate the rate of erosion?

1) Overcultivating fields through poor planning or excessive tilling

2) Overgrazing rangeland with more livestock than the land can support

3) Clearing forests on steep slopes or with large clear cuts

Define soil

A complex plant supporting system consisting of disintegrated rock, organic matter, air, water, nutrients, and microorganisms.

What are the 5 factors that determine the properties of soil?

1)Organisms: plants and decomposers add organic matter to soil over time

2)Climate: soil forms faster in warm, wet climates (heat and moisture speed most physical, chemical and biological processes)

3)Topography: hills and valleys affect exposure to sun, wind, and water, and they influence how soil moves.

4)Parent Material: its attributes influence properties of the resulting soil

5)Time: soil formation can take decades, centuries or millennia

What are the soil horizons?

O horizon-organic (litter layer)

A horizon-topsoil

E horizon-eluviated (leaching layer)

B horizon-subsoil

C horizon-weathered parent material

R horizon-rock (parent material)

What is "Zone of Leaching"

E horizon where minerals are generally transported downward as a result of leaching

What are the physical properties of soil?

1)Soil Color-darker soils are usually rich in organic matter

2)Soil Texture-soils with large particles are porous and allow water to pass through quickly beyond the root of plants so the plants require more frequent irrigation. Soils with smaller particles provide slower infiltration but less oxygen; makes it difficult for water and air to pass. Medium size pores are best for plants.

3)Soil Structure-a measure of the "clumpieness" of soil. Intermediate clumpiness is best bc repeated tilling can compact soil, reducing its ability to absorb water and inhibiting the penetration of plants roots.

What are the chemical properties of soil?

1)Soil pH-plants can die in soils to acidic or alkaline

2)Cation Exchange-plant roots donate hydrogen ions to the soil in exchange for nutrient ions, which the soil particles then replenish by exchange with soil water

How can soil be degraded?

Intensive and unsustainable agriculture, deforestation and urban development.

What are ores?

A mineral, or group of minerals, from which we extract metal

Define reserve

A supply of a commodity not needed for immediate use but available if required. Ex: reservoir behind a dam used to generate electricity

What are the 4 types of surface mining? (Pg 649 to find explanation in paragraph)

1)Strip Mining- removes surface layers of soil and rock

2)Subsurface Mining-miners work underground

3)Open Pit Mining- creates immense holes in the ground

4)Placer Mining- uses running water to isolate minerals

5)Mountaintop Mining-reshapes ridges and can refill valleys

What are tailings or mineral spoilings?

Portions of ore left over after metals have been extracted in mining. Mineral spoilings are

What does reclamation mean?

Restoration of surface mined sites following mining. The aim is to restore the site to a condition similar to its condition before mining.

What are the hazards of subsurface mining?

Dynamite blasts, natural gas explosions, collapsing shafts and tunnels, and inhaling toxic fumes and coal dust leading to fatal black lung disease.

Explain 2 laws that help with regulating mining

In the US, the 1977 surface mining control and reclamation act mandates restoration efforts, requiring companies to post bonds to cover reclamation costs before mining can be approved. (If the company fails to restore the land, the gov't will have money to do so)

Where is most of earths freshwater found?

Over 68 percent of the fresh water on Earth is found in icecaps and glaciers, and just over 30 percent is found in ground water. Only about 0.3 percent of our fresh water is found in the surface water of lakes, rivers, and swamps.

Define aquifers

An underground water reservoir. (permeable layers of rock and sediment)

What is the difference between a confined and unconfined aquifer?

A confined, or artesian, aquifer is a water bearing porous layer of rock, sand, or gravel that is trapped BETWEEN an upper and lower layer of less permeable substrate, such as clay. The water in a confined aquifer is UNDER PRESSURE because it is trapped between two impermeable layers. An unconfined aquifer is water bearing porous layer of rock, sand, or gravel that lies ATOP a less permeable substrate. The water in an unconfined aquifer is NOT UNDER PRESSURE because there is no impermeable upper layer to confine it.

What is a water table?

The upper limit of groundwater held in an aquifer.

What is groundwater recharge?

Groundwater recharge (or deep drainage or deep percolation) is a hydrologic process where water moves downward from surface water to groundwater; this refills aquifers which we have taken from.

How do confined and unconfined aquifers affect the rate of groundwater recharge.

A confined aquifer would have a slower groundwater recharge rate because it has a less permeable layer above it, resembling clay, that the water would have to soak through.

Define springs. What are some uses of springs?

Springs are

Define artesian wells

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Explain the cone of depression

Occurs in an aquifer when groundwater is pumped too quickly from a well.

What are floodplains? What are some benefits of floodplains? How do they get nutrient rich soil?

A floodplain is a region of land over which a river has historically wandered and periodically floods. Floodplains get nutrient rich soil due to the frequent deposition of silt from flooding. This leads to the benefits of thriving agriculture and productive and species rich riparian (riverside) forests.

What classifies a lake? What is the difference between oligotrophic and eutrophic?

Pg.404 Oligotrophic lakes have low nutrient and high oxygen levels which eutrophic lakes have high nutrient and low oxygen levels.

What are some effects of a drought on soil?

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Define leeve. What are benefits and drawbacks?

A leeve, or a dike, is a long raised mound of earth erected along a river bank to protect against floods by holding rising water in the main channel. A benefit of dikes is the prevention of flooding, while a drawback is that it can worsen flooding by forcing water to stay in channels and accumulate, building up enormous energy and leading to occasional catastrophic overflow events. Engineering rivers to stay in their channels often end up increasing the frequency of floods in downriver areas.

Define dams. What are benefits and drawbacks.

Dams are any obstruction placed in a river or stream to block the flow of water so that water can be stored in a reservoir. They benefit by preventing floods, providing drinking water, facilitating irrigation and generating electricity. Drawbacks are cost, reservoir flooding, and slowing the rivers flow so that suspended sediment settles behind the dam. This causes marshes to erode, degrading coastal land. The reservoir can also become polluted not allowing it to be used for drinking water.

Define dikes. Where are these most common and why?

A dike is a long raised mound of earth erected along a river bank to protect against floods by holding rising water in the main channel. These are most common in floodplains to protect from flooding.

Define aqueducts. Give benefits and drawbacks.

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Define desalinization. What are the two techniques?

Desalinization is the removal of salt from seawater.The two techniques are 1)Distilling-evaporating allotments of ocean water with heat and then condensing the vapor. 2)Reverse osmosis-forcing water through membranes through filter out salts. (most popular) Its is expensive, kills aquatic life at water intakes, uses a lot of fossil fuel and generates concentrated salty waste.Done in wealthy oil rich nations where water is scarce.

List the 3 top uses of freshwater.

1)70% agriculture

2)20& industry

3)10%household

What is the top use of freshwater in households?

Flushing toilets-41%

What are the different types of irrigation? EXPLAIN EACH

1. furrow - 65% efficient

2. flood - 70-80% efficient

3. spray - 75-95% efficient

4. drip - over 95% efficient (reduces weed growth)

Define hydroponic agriculture

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What are some ways water is used industrially?

a. in US, ½ water goes towards electricity

b. cools machinery (steam)

c. refines metals

d. used to make paper

List some ways in which you can conserve water.

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Demographic Transition

As a country moves from a subsistence economy to industrialization, it undergoes a predictable shift in population growth.