MH

APES Unit 4 PPT

Unit 4: Earth Systems and Resources

Topic 4.1: Plate Tectonics

  • Convergent Boundaries

    • Result in mountains, island arcs, earthquakes, and volcanoes.

  • Divergent Boundaries

    • Cause seafloor spreading, rift valleys, volcanoes, and earthquakes.

  • Transform Boundaries

    • Primarily associated with earthquakes.

  • Mapping Plate Boundaries

    • Global distribution maps indicate the locations of volcanoes, island arcs, earthquakes, hot spots, and faults.

  • Earthquake Mechanism

    • Occur when stress accumulates and exceeds the capacity of a locked fault, releasing stored energy.

Plate Boundaries Around the World

  • Major tectonic plates include:

    • Eurasian Plate

    • North American Plate

    • Pacific Plate

  • 'Ring of Fire': A zone of high seismic and volcanic activity encircling the Pacific Ocean, notable for numerous active volcanoes.

Different Types of Plate Boundaries

  • Type of Margin

    • Divergent: Spreading - constructive (new oceanic lithosphere created).

    • Convergent: Subduction - destructive (oceanic lithosphere destroyed).

    • Transform: Lateral sliding - conservative (no new or old plate consumption).

  • Topography Effects:

    • Divergent: Ridge/Rift

    • Convergent: Trench

    • Transform: No major topographical effects.

  • Volcanic Activity

    • Divergent and convergent boundaries can lead to significant volcanic activity; transform boundaries generally do not.

Mechanisms of Plate Boundaries

  • Divergent Boundary: Plates move apart, creating new lithosphere at mid-ocean ridges.

  • Convergent Boundary: One plate sinks below another (subduction). Landforms features such as volcanic arcs and trenches.

  • Transform Boundary: Plates slide past each other, leading to earthquakes along vertical faults.

Topic 4.2: Soil Formation and Erosion

  • Soil Formation Process

    • Occurs through weathering, transportation, and deposition of parent material.

  • Soil Horizons

    • Classified based on composition and organic material presence.

  • Erosion

    • Soil can be eroded by wind or water, emphasizing the importance of soil conservation for water quality.

Soil Particles and Size

  • Particle Sizes:

    • Sand: 0.05mm - 2mm

    • Silt: 0.002mm - 0.05mm

    • Clay: <0.002mm

Soil and Rock Particle Sizes

  • Rock fragments and sizes ranging from clay to boulders.

  • Unified Sieve standard sizes range used to classify soil types.

Soil Horizons Profile

  • A (Surface Horizon): Organic material (humus)

  • A Horizon: Topsoil; B Horizon: Subsoil; C Horizon: Partially weathered parent material; R Horizon: Bedrock.

Topic 4.3: Soil Composition and Properties

  • Water Holding Capacity: Varies with soil type, influencing productivity and fertility.

  • Properties Affecting Soil:

    • Particle size impacts porosity, permeability, and fertility.

  • Various tests available for chemical and physical properties of soil aiding agricultural decisions.

  • Soil Texture Triangle: Diagram for classifying soil types based on clay, silt, and sand ratios.

Soil Characteristics

  • Porosity: Amount of pore space in soil.

  • Permeability: Rate water infiltrates into soil.

  • Fertility: Measurement of soil nutrient content.

Topic 4.4: Earth’s Atmosphere

  • Composition: Major gases present in the atmosphere, each with specific abundance.

  • Layers of the Atmosphere: Differentiated by temperature gradients:

    • Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere.

Topic 4.5: Global Wind Patterns

  • Formation: Wind patterns driven by solar radiation intensity differences at the equator and influenced by the Coriolis effect.

Topic 4.6: Watersheds

  • Watershed Characteristics: Defined by area, length, slope, soil, vegetation types, and divides.

Topic 4.7: Solar Radiation and Earth’s Seasons

  • Solar Radiation: Main energy source, varies with season and latitude.

  • Intensity: Highest at the equator; decreases towards poles.

  • Seasonal Variation: Influenced by Earth's axial tilt affecting daylight duration and seasonal changes.

Topic 4.8: Earth’s Geography and Climate

  • Influencing Factors: Weather and climate affected by solar energy, geological, and geographic features.

  • Rain Shadow Effect: A drier region created when a higher elevation area blocks precipitation.

Topic 4.9: El Niño and La Niña

  • Phenomena Overview: Linked to ocean surface temperature changes impacting global weather patterns.

  • Influences vary by geographical location.