Notes, summaries, assignments, exams, and problems for Geology

1. What are the innermost layers of Earth?

The inner core is the innermost physical layer of the Earth. The core is the innermost chemical layer.

2. What evidence indicates that the outer core is liquid?

Evidence from earthquake waves indicates that the outer core is liquid.

3. How does Earth generate a magnetic field?

It surrounds Earth.

4. Compare the lithosphere and the asthenosphere

The lithosphere is a rigid layer. The asthenosphere is a plastic layer.

5. How is the crust different from the mantle?

The mantle has more iron. The crust is less dense than the mantle.

6. What are the four layers of the mantle?

• Lithosphere
• Asthenosphere
• Uppermost mantle
• Lower mantle

7. Which layer of the mantle has the greatest pressure? Explain

The lower mantle because pressure... Continue reading "Earth's Layers and Systems: Composition and Properties" »

1. Global Concepts & Protocols

Problems and Global Issues

• Resource Depletion: Finite resources, renewable resources, and resource degradation.
• Environmental Pollution: Air, water, and soil pollution, including causes and mitigation methods.
• Global Climate Change (全球气候变化)
  • Key Substances (GHGs): Primarily $\text{CO}_2$ (Carbon Dioxide), $\text{CH}_4$ (Methane), $\text{N}_2\text{O}$, and CFCs.
  • Mechanism (Greenhouse Effect): Solar shortwave radiation enters Earth $\rightarrow$ Ground heats up and emits longwave infrared radiation $\rightarrow$ GHGs absorb this heat in the atmosphere $\rightarrow$ Global warming.
  • Consequences: Sea level rise, extreme weather, loss of biodiversity.
  • Corresponding Conventions: Kyoto Protocol & Paris Agreement.

Earth's Fundamental Motions

Two Primary Earth Movements

• Rotation: The spinning of Earth on its axis. Consequences: Day and night cycle, Coriolis effect.
• Revolution: The orbiting of Earth around the Sun. Consequences: Seasons, varying daylight hours.

Earth's Interconnected Spheres

The Four Spheres of Earth

• Atmosphere: The layer of gases surrounding Earth. It provides air for breathing and protects from harmful solar radiation.
• Hydrosphere: All water on Earth, including oceans, rivers, lakes, and glaciers. It plays a key role in the water cycle and supports aquatic life.
• Lithosphere: The rigid outer layer of Earth, consisting of the crust and upper mantle. It forms landmasses and ocean floors.
• Biosphere: All living organisms and their interactions with

What Are Rocks?

Rocks are solid aggregates of minerals. They are more common than individual minerals.

The Three Types of Rocks

There are three different types of rocks:

• Igneous
• Sedimentary
• Metamorphic

Igneous Rocks

Igneous rocks are formed from magma that has cooled and solidified.

Plutonic Rocks

These rocks are formed deep underground, and the cooling process is very slow. The slower the cooling process, the larger the crystals formed (e.g., granite).

Volcanic Rocks

These rocks are formed on the surface, often related to volcanoes. The cooling process is very quick, preventing the formation of visible crystals (e.g., obsidian, pumice).

Sedimentary Rocks

Sedimentary rocks are made of fragments of other rocks (sediments). They often contain fossils.

Formation

Unique Properties of Water

Water is a molecule that consists of two hydrogen atoms and one oxygen atom. Water is special because its highest density is in liquid form rather than solid form, which is the case for most substances. It is also called the “universal solvent” because of its ability to dissolve more substances than any other liquid found on Earth, due to its unique chemical composition and physical attributes.

Cohesion and adhesion are two very important water properties.

• Cohesion is the property that allows water molecules to stick to one another (e.g., a drop of water holding its shape).
• Adhesion is the property that allows water molecules to stick to another substance instead of slipping off.
• Capillary action is the movement of

1. Earth's Position in Space

   • Earth orbits the Sun at 67,000 mph, maintaining a delicate balance between gravity and velocity.
   • Life exists due to Earth's stable distance from the Sun, allowing liquid water and habitable temperatures.

2. Earth as an Energy and Matter System

   • All changes on Earth result from energy: inputs, storage, transformation, or outputs.

   • Two Primary Energy Sources:

     • Solar Energy: Drives photosynthesis, weather, and food webs.
     • Internal Earth Energy: Causes tectonic activity, earthquakes, and volcanic eruptions.

3. Solar Energy Pathways

   • Photosynthesis: Converts sunlight into chemically bonded energy (food, fossil fuels).
   • Heat Energy: Drives weather systems (e.g., hurricanes, tornadoes).

4. Energy Flow

   • Energy flows into, through, and out of Earth's

A widely used mathematical framework for Gaussian plume model assumes that the concentration distribution of pollutants in cross-sections perpendicular to the wind direction follows a normal distribution in both vertical and horizontal directions. The model is applied under specific assumptions:

1. Point source emissions with low vertical velocities.
2. Emissions at temperature ($T$) equal to or slightly above ambient air.
3. Stable atmospheric conditions, at least over one-hour intervals.
4. Flat and uniform soil with little surface roughness.

Hypotheses for the Model

• Wind speed and direction: constants.
• Conditions of the parameters that characterize the dispersive properties of the atmosphere: constants.
• Soil: uniform and flat.

General Diffusion Equation

The general... Continue reading "Gaussian Plume Model: Pollutant Dispersion Fundamentals" »

Understanding Earth's Dynamic Processes

Earthquakes and volcanic eruptions are fundamental geological events caused by movements within the Earth's lithosphere, specifically the interaction of tectonic plates.

The Earth's Moving Plates

The Earth's outer layer is composed of large sections called plates. These plates consist of two primary types of crust:

• Continental Crust: This type of crust is generally older, lighter, and does not readily sink back into the mantle. It is considered permanent.
• Oceanic Crust: In contrast, oceanic crust is younger, heavier, and can sink (subduct) into the mantle. It is constantly being destroyed and replaced through geological processes.

Plate Margins: Where Plates Interact

The boundaries where two plates meet are... Continue reading "Earth's Dynamic Plates: Earthquakes, Volcanoes, and Landforms" »

Understanding Earth's Atmosphere

Atmospheric Composition Evolution

Primitive Atmosphere: Composed of water vapor, carbon dioxide, nitrogen, hydrogen, ammonia, methane, and other oxides, but notably *no oxygen*.

Present Atmosphere: Consists of approximately 78% nitrogen, 21% oxygen, 1% carbon dioxide, water vapor, and trace gases like argon. The ozone layer later formed from oxygen.

Atmospheric Layers (In Order)

• Ionosphere: Temperature around 1,000 ºC.
• Mesosphere: Approximately 40 km thick.
• Stratosphere: Approximately 30 km thick. Temperature increases from 0 ºC at its upper limit to 70 ºC at its lower limit (Note: The original text stated an increase *to* 0ºC, which is inconsistent with standard models; this reflects the general structure).
• Troposphere: