Geology and Earth Resources Study Notes

From inside out:
- Inner Core - the innermost layer, primarily composed of solid iron and nickel, with extreme temperatures reaching up to 5,400 degrees Celsius.
- Outer Core - composed of liquid iron and nickel, generating the Earth's magnetic field.
- Mantle
- Crust
- Lithosphere: Outermost rigid rock layer composed of tectonic plates.
- Asthenosphere: Lower mantle consisting of hot, soft rock.
- The lithosphere plates float on the asthenosphere.

Core:
- Interior composed of dense, intensely hot metal, predominantly iron.
- Generates the magnetic field enveloping the Earth.
Mantle:
- Hot, pliable layer surrounding the core, less dense than the core.
Crust:
- Cool, lightweight, brittle outermost layer that floats on the mantle.
- Most abundant element in the crust: Oxygen (46.6%).

Asteroid Impact: Related to the extinction of dinosaurs.
Floods: Take the greatest number of lives.
Wind: Causes the greatest property damage.
Earthquakes:
- Sudden movements of the Earth’s crust where one rock mass slips past another.
- Caused by the release of accumulated energy as rocks in the lithosphere suddenly shift or break.
- Occur along faults.
- Energy released as seismic waves.
- Focus: Site where the earthquake begins.
- Epicenter: The Earth's surface directly above the focus.

The study of processes by which lithospheric plates move over the asthenosphere.
Types of Plate Boundaries:
- Divergent Boundary:
- Plates move apart; molten rock wells up from the mantle.
- Common earthquakes and magma rise from the mantle to the surface, forming new oceanic crust.
- Causes: Rifts, seafloor spreading, earthquakes, volcanoes.
- Example: Mid-Atlantic Ridge.
- Convergent Boundary:
- Plates collide, moving toward each other.
- Involves subduction: one plate descending beneath the other.
- Causes: Mountain ranges formation, island arcs, ocean trenches.
- Examples: Himalayas, Japan (island arcs).
- Transform Boundary:
- Plates slide past each other, moving in opposite but parallel directions.
- Causes: Rift valleys due to erosion along fault lines; earthquakes.
- Example: San Andreas Fault (California).

Divergent Boundary:
- Newly formed oceanic crust.
- Geologic Activities: Volcanoes, earthquakes, new crust formation.
- Real-world Examples: Iceland, Red Sea.
Convergent Boundary:
- Can form mountain ranges, volcanoes, and island arcs due to pressure and friction.
- Examples include oceanic trenches and volcanic arcs such as the Kuril Arc and Aleutian Arc.
Transform Boundary:
- Earthquakes due to unlocked energy.
- Example discusses various fault lines in California, including San Andreas Fault.

Good places for geothermal energy are at plate boundaries.
The Ring of Fire lines the edges of the Pacific Ocean.
Geothermal resources of the United States are associated with various plate boundaries, including converting the heat from geothermal sources into energy.

Common at plate boundaries.
Typical effects include:
- Landslides: Avalanche of rocks, soil, debris.
- Tsunamis: Giant sea waves if the epicenter is near/on the ocean floor.

Charles Richter (1935): Developed the Richter scale to measure the magnitude of energy released by an earthquake.
- Each unit on the scale represents 30 times more energy released than the one below.
Seismograph: A device that measures seismic waves, assessing both the strength and length of these waves.

Seismic and volcanic activity highlighting earthquakes and volcanoes are concentrated around the edges of the Pacific Ocean.
Numerous plate types (divergent, convergent, transform) are found here, often leading to volcanic arcs and earthquake sites such as Mt. Saint Helens.

Magma: Cools to form igneous rock which constitutes the Earth’s crust.
Fertile soils often derive from weathered volcanic material.
Volcanic dust and sulfur can reduce sunlight and temperature by creating atmospheric aerosols.

Minerals:
- Inorganic solids with crystalline structures, occurring naturally in Earth’s crust.
- Examples:
- Metallic: Iron, aluminum, copper - malleable, good conductors of heat and electricity.
- Non-metallic: Sand, stone, salt, phosphates.
Important Minerals and Their Uses:
- Aluminum: Alloy in motor vehicles and packaging.
- Iron: Used in steel alloys and manufacturing.
- Gold: Used in jewelry and dentistry.
- Mercury: Applications in electronics and batteries.

Environmental Impacts:
- Habitat destruction, aquifer depletion, water pollution, air pollution, acid rain.
- Acid Mine Drainage: Contamination from mining runoff, posing significant environmental risks.

Surface Mining Control and Reclamation Act (1977): Mandates restoration of mining lands, particularly when not profitable to continue.
Restoration involves: planting vegetation, replacing topsoil, and structural improvements to prevent erosion.

Surface Mining:
- More common and less costly but more damaging to the environment.
- Includes open-pit and strip mining techniques.
Subsurface Mining:
- Involves digging below 100 meters, considered more perilous but environmental impacts are often less severe, involving shaft and slope mining methods.

The long-term extraction processes and mining techniques significantly impact ecosystems and the environment; thus, responsible mining practices and regulatory guidelines are critical to sustaining environmental integrity.

Grants companies the right to mine on federal public lands.
The law lacks environmental protections and oversight, which raises concerns regarding mining practices.