Comprehensive Notes on Geology, Soil Science, Atmosphere, and Climate

Unit 4 Terms and Concepts

Geology (4.1)

  • Sedimentary Rock:

    • Formation through processes of erosion, which can be caused by:
    • Water: A major force in transporting and shaping sediment.
    • Wind: Contributes to erosion and deposition, especially in arid regions.

  • Lithosphere:

    • Comprises the Earth's crust and the uppermost portion of the mantle, forming a rigid outer layer.

  • Earth's Interior Structure:

    • Crust: The outermost layer of the Earth.
    • Mantle: Situated beneath the crust, consists of semi-solid rock that flows slowly.
    • Core: The innermost layer, primarily composed of iron and nickel, divided into a solid inner core and a liquid outer core.

  • Plate Tectonics:

    • A scientific theory explaining the movement of tectonic plates on the Earth's surface.
    • Convergent Boundary: Plates collide, leading to mountain building or subduction zones.
    • Divergent Boundary: Plates move apart, commonly creating new crust via volcanic activity.
    • Transform Boundary: Plates slide past one another horizontally, often causing earthquakes.

  • Creation of Landforms:

    • Various geological processes contribute to the formation of landforms, including:
    • Mountain Building: Occurs mainly at convergent plate boundaries.
    • Erosion: The process of weathering and transportation of materials.
    • Volcanoes: Eruptive activity can create mountains and affect surrounding areas.
    • Earthquakes: Caused by the movement of tectonic plates, can reshape landscapes.
    • Tsunami: A series of ocean waves caused by seismic disturbances, leading to significant coastal changes.

Soil - Don't Call it Dirt! (4.2 & 4.3)

  • Components of Soil:

    • Soil is a complex natural resource with several components:
    • Inorganic Materials: Minerals and non-living matter.
    • Organic Materials: Decomposed plants and animals.
    • Nutrients: Essential for plant growth, derived from organic decomposition.
    • Pore Space: Crucial for water retention and air circulation.

  • Organisms in Soil:

    • While organisms technically are not counted as part of the soil, they play critical roles in soil health and ecosystems.
    • Examples include:
    • Nitrogen-Fixing Bacteria: Convert atmospheric nitrogen into a form usable by plants.
    • Mycorrhizal Fungi: Assist plants in nutrient uptake and improve soil structure.

  • Soil Formation:

    • Often occurs during ecological succession, with various factors influencing it:
    • Organic Material (from organisms).
    • Inorganic Material (known as parent material).
    • Topography: The arrangement of natural and artificial physical features.
    • Climate: Conditions affecting soil development, including temperature and precipitation.
    • Time: Soil takes time to develop and mature.

  • Soil Horizons:

    • Layers within the soil profile that differ in properties. Commonly categorized into zones:
    • Topsoil: Rich in organic material and nutrients.
    • Subsoil: Contains minerals leached from the upper layers.
    • Parent Material: The underlying geological material from which soil forms.

  • Soil Particles:

    • Different types of soil particles include:
    • Sand: Coarse particles, high drainage.
    • Silt: Medium size, retains moisture.
    • Clay: Fine particles, high cation exchange capacity (CEC), retains water and nutrients.

  • Soil Triangle:

    • A tool used to classify soil types based on their texture and relative proportions of sand, silt, and clay.

  • Soil Erosion:

    • The removal of the top layer of soil due to water, wind, and human activities.

Earth's Atmosphere (4.4-4.6)

  • Primary Gases:

    • The atmosphere is made up of several key gases, including nitrogen and oxygen.

  • Oxygen Formation:

    • When: Oxygen started accumulating in the atmosphere approximately 2.5 billion years ago due to photosynthetic organisms (cyanobacteria).
    • Why: The process of photosynthesis converts carbon dioxide and water into glucose and oxygen, contributing to atmospheric oxygen levels.

  • Ozone and Ozone Layer:

    • Ozone (O₃) forms a layer in the stratosphere that protects Earth from harmful ultraviolet radiation.

  • Atmospheric Window:

    • The range of wavelengths in the electromagnetic spectrum that can pass through the atmosphere, crucial for life on Earth.

  • Hydrologic Cycle Portions:

    • Components of the water cycle as it pertains to the atmosphere, including evaporation, condensation, and precipitation.

  • Atmospheric Structure:

    • Troposphere: The lowest layer where weather occurs and where most life exists.
    • Stratosphere: Above the troposphere, contains the ozone layer.

  • Air Pressure:

    • Influenced by altitude, can be high or low depending on the temperature and humidity of the air.

  • Wind Patterns:

    • Hadley Cells: Circulate warm air from the equator towards the poles.
    • Ferrel Cells and Polar Cells: Moderate the wind patterns in different latitudes.

  • High and Low-Pressure Systems:

    • Generally influence weather patterns and characteristics of regions, with wet tropics near the equator and dry deserts typically found at 30° latitude north and south.

  • Coriolis Effect:

    • The effect of Earth's rotation on the direction of winds and currents, causing them to curve rather than travel in a straight line.

  • Watersheds:

    • Regions of land that drain into a particular body of water, playing a significant role in hydrology and ecology.

Climate (4.7-4.9)

  • Electromagnetic Spectrum:

    • Solar energy consists of various wavelengths, including ultraviolet and visible light, which are most relevant for life on Earth.

  • Effects of the Atmosphere:

    • The atmosphere acts as a filter, affecting the intensity and quality of solar radiation reaching the Earth's surface via the atmospheric window.

  • Effect of Latitude:

    • Latitude affects climate significantly due to the curvature of the Earth, influencing solar radiation received at different regions.

  • Seasonality:

    • Caused by the Earth's axial tilt and its revolution around the Sun, leading to variations in light and temperature across seasons.

  • Milankovitch Cycles:

    • Long-term changes in Earth's climate caused by variations in its orbit:
    • Wobble: Changes in Earth's axial tilt.
    • Tilt: Variations in the angle of Earth's tilt.
    • Orbit: Eccentricity changes in Earth's orbit around the Sun.

  • Perihelion & Aphelion:

    • Perihelion: The point where Earth is closest to the Sun.
    • Aphelion: The point where Earth is farthest from the Sun.

  • Long-Term Temperature and CO₂ Data:

    • Historical data showing trends and fluctuations in Earth's temperature and carbon dioxide levels, important for understanding climate change.

  • Geography’s Effect on Climate:

    • Various geographical features can significantly influence local and regional climates:
    • Ocean Currents: Can moderate temperatures and precipitation patterns.
    • Elevation/Altitude: Higher altitudes generally result in cooler temperatures, known as the lapse rate.
    • Rain Shadow Effect: Regions blocked by mountains receive less precipitation on the leeward side.
    • Coastal Areas: Experience daily temperature cycles and different climates compared to continental regions due to large water bodies.

  • Effect of Proximity to Oceans:

    • Being near oceans or large water bodies typically moderates temperature extremes and increases humidity in the local climate.

  • The Great Lakes:

    • The large freshwater lakes in North America influence regional climates, often leading to milder winters and cooler summers compared to inland areas.

  • El Niño:

    • A climatic phenomenon characterized by the warming of ocean surface temperatures in the central and eastern tropical Pacific, affecting weather patterns globally.