Rocks and Soil

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"APES: Rocks and Soil" Evernote Notebook

Plate Tectonics

Convergent boundaries can result in the creation of mountains, island arcs, earthquakes, and volcanoes.
Divergent boundaries can result in seafloor spreading, rift valleys, volcanoes, and earthquakes.
Transform boundaries can result in earthquakes.
Maps that show the global distribution of plate boundaries can be used to determine the location of volcanoes, island arcs, earthquakes, hot spots, and faults.
An earthquake occurs when stress overcomes a locked fault, releasing stored energy.

Mining and Mineral Resources

As the more accessible ores are mined to depletion, mining operations are forced to access lower grade ores. Accessing these ores requires increased use of resources that can cause increased waste and pollution.
- Why are low grade ores more common now?
- How do mineral deposits form on Earth?

Surface mining is the removal of large portions of soil and rock, called overburden, in order to access the ore underneath. An example is strip mining, which removes the vegetation from an area, making the area more susceptible to erosion.
- What are some other types of mining?
- What are some environmental problems with the different types of mining, specifically subsurface vs. surface mining?
Mining wastes include the soil and rocks that are moved to gain access to the ore and the waste, called slag and tailings that remain when the minerals have been removed from the ore. Mining helps to provide low cost energy and material necessary to make products. The mining of coal can destroy habitats, contaminate ground water, and release dust particles and methane.

As coal reserves get smaller, due to a lack of easily accessible reserves, it becomes necessary to access coal through subsurface mining, which is very expensive.

The Rock Cycle

Types of Weathering

Soil

Soils are formed when parent material is weathered, transported, and deposited.
Soils are generally categorized by horizons based on their composition and organic material.

- Why is soil such an important resource?
- What is needed in soil for it to be fertile and productive?
- What are the soil horizons? What are the characteristics of each? Which horizon is the most nutrient-rich?
- How does the soil type affect the fertility of the soil and what can be grown there? For example, rainforest soil vs. grassland soil?

Water holding capacity—the total amount of water soil can hold—varies with different soil types. Water retention contributes to land productivity and fertility of soils.
- How does the size of the soil particle influence the water-holding capacity of the soil?

The particle size and composition of each soil horizon can affect the porosity, permeability, and fertility of the soil.
- Rank the soil particles from smallest to largest.
- How does the size of the soil particle influence the porosity, permeability, and fertility of the soil?

There are a variety of methods to test the chemical, physical, and biological properties of soil that can aid in a variety of decisions, such as irrigation and fertilizer requirements.
- What are some of these tests?
- Why are they important?
- What can a soil test result tell you about the health of the soil and what can be grown there?

A soil texture triangle is a diagram that allows for the identification and comparison of soil types based on their percentage of clay, silt, and sand.
- Know how to use a soil texture triangle.
- If a soil has 25% clay, 50% sand, and 25% silt, what type of soil is it? Know some basic properties of this soil (will it drain well? etc...)

Threats to Soil

Salinization occurs when the salts in groundwater remain in the soil after the water evaporates. Over time, salinization can make soil toxic to plants.

- What are naturally occurring pollutants found in soil that can hinder plant growth?
- If soil erosion is happening at a greater rate than new soil can form, what will eventually happen to the soil in that region?
- What are some kinds of pollutants that could not easily be removed from soil?

Erosion

Soils can be eroded by winds or water. Protecting soils can protect water quality as soils effectively filter and clean water that moves through them.
- What are the different types of erosion?
- What are some ways we can reduce the erosion of soil?

Overgrazing occurs when too many animals feed on a particular area of land. Overgrazing causes loss of vegetation, which leads to soil erosion.
- Which industry is primarily responsible for overgrazing?
- In what area of the country is the land MOST susceptible to overgrazing?
Less consumption of meat could reduce CO₂, methane, and N₂O emissions; conserve water; reduce the use of antibiotics and growth hormones; and improve topsoil.
- HOW could reduced meat consumption reduce all of the above?

Climate change can affect soil through changes in temperature and rainfall, which can impact soil’s viability and potentially increase erosion.
- HOW can climate change increase erosion?

Desertification

Overgrazing can cause desertification. Desertification is the degradation of low precipitation regions toward being increasingly arid until they become deserts.
Desertification is permanent.
- What are some things we can do to reduce the threat of desertification?

Soil Conservation

The goal of soil conservation is to prevent soil erosion. Different methods of soil conservation include contour plowing, windbreaks, perennial crops, terracing, no-till agriculture, and strip cropping.
- Know each of these methods above and be able to describe them.

Strategies to improve soil fertility include crop rotation and the addition of green manure and limestone.
- Know each of the strategies above and be able to describe them.