Unit 4_ Earth Systems

Unit 4: Earth Systems 1

4.1 Plate Tectonics 2

Objectives, Essential Knowledge & Skills

  • Learning Objective: Understand geological changes and events at plate boundaries.

    • ERT-4.A.1: Convergent boundaries result in mountains, island arcs, earthquakes, and volcanoes.

    • ERT-4.A.2: Divergent boundaries lead to seafloor spreading, rift valleys, and volcanoes.

    • ERT-4.A.3: Transform boundaries cause earthquakes.

    • ERT-4.A.4: Visual maps depict the global distribution of plate boundaries and correlate to earthquakes and volcanism locations.

    • ERT-4.A.5: Earthquakes occur when stress overcomes a locked fault, releasing stored energy.

Earth’s Structure

  • Core: Solid core composed of nickel and iron, producing intense heat.

  • Mantle: Liquid magma layer surrounding the core.

  • Asthenosphere: Solid, flexible layer beneath the lithosphere.

  • Lithosphere: Rigid layer broken into tectonic plates.

  • Crust: The outermost layer of the lithosphere.

Plate Boundaries

Divergent Plate Boundary

  • Plates move away from each other.

  • Caused by rising magma from the mantle, resulting in:

    • Mid-ocean ridges

    • Volcanoes

    • Rift valleys (on land)

Convergent Plate Boundary

  • Plates move towards each other.

  • Features include:

    • Subduction zones (one plate forced beneath another)

    • Formation of mountains, island arcs, earthquakes, and volcanoes.

Transform Fault Plate Boundary

  • Plates slide past each other, resulting in:

    • Earthquakes due to build-up pressure and sudden released energy.

Convection Cycles (Divergent)

  • Rising magma cools and expands, forcing oceanic plates apart.

  • Results in:

    • Mid-ocean ridges

    • New lithosphere formation through solidification.

Convergent Boundaries Breakdown

Continental-Continental

  • Creates mountains (e.g., Himalayas).

Oceanic-Continental

  • Dense oceanic plate subducts beneath continental plate.

  • Leads to trenches, coastal mountains (e.g., Andes).

Oceanic-Oceanic

  • One oceanic plate subducts, forming mid-ocean volcanoes and island arcs.

Transform Fault Boundary

  • Mainly associated with earthquakes due to plate friction.

  • Stress accumulates until a seismic event occurs.

Predictive Model: Tectonic Map

  • Ring of Fire: High volcanic activity surrounding the Pacific Plate.

  • Hotspots: Areas of intense volcanic activity (e.g., Iceland, Hawaii).

  • Transform faults indicate likely earthquake zones.

4.2 Soil Formation & Erosion

Objectives, Essential Knowledge & Skills

  • Learning Objective: Describe soil characteristics and formation.

    • ERT-4.B.1: Soils form from weathering, transport, and deposition.

    • ERT-4.B.2: Categorization of soil by horizons based on composition.

Definitions and Composition of Soil

  • Soil Composition: Mix of geologic (rock) and organic components like:

    • Sand, silt, clay.

    • Humus: decomposed organic matter.

    • Nutrients: ammonium, phosphates.

  • Nutrient Recycling: Soil hosts decomposers that return nutrients to plants.

Weathering and Erosion

Weathering

  • Breakdown of rocks into smaller pieces through:

    • Physical processes: wind, rain, freezing.

    • Biological processes: tree roots.

    • Chemical processes: acid rain.

Erosion

  • Transport of weathered materials by wind/water and their subsequent deposition in new areas.

Soil Formation Influences

  • Parent Material: Influences soil pH and nutrient content.

  • Topography: Affects erosion (steep slopes foster it; flatlands favor deposition).

  • Climate: Temperature and precipitation affect breakdown rates.

  • Organisms: Soil organisms contribute to the breakdown of organic matter.

Soil Horizons

  • O-Horizon: Organic materials layer.

  • A-Horizon: Topsoil with rich microbial activity.

  • B-Horizon: Subsoil with minerals, less organic matter.

  • C-Horizon: Least weathered material, close to bedrock.

Soil Degradation

  • Loss of soil's ability to support plant growth due to:

    • Loss of topsoil from tilling or vegetation loss.

    • Compaction from machines, livestock.

    • Nutrient depletion from repetitive cropping.

4.3 Soil Composition & Properties

Objectives, Essential Knowledge & Skills

  • Learning Objective: Analyze differences in soil types and properties.

    • ERT-4.C.1: Water retention depends on soil type and texture.

    • ERT-4.C.2: Particle size impacts porosity and permeability.

Soil Properties

  • Particle Size Order: Sand > Silt > Clay.

  • Soil Texture: % of sand, silt, clay influences how soil holds nutrients and water.

  • Porosity: Amount of open space in soil affecting air/water retention.

Fertility and Nutrient Factors

  • Key nutrients for fertility include nitrogen (N), phosphorus (P), potassium (K).

  • Organic matter enhances nutrient holding capacity.

4.4 Watersheds

Objectives & Essential Knowledge

  • Learning Objective: Understand watershed characteristics and impacts.

  • Characteristics: define area, slopes, soil types, etc.

Definition of Watersheds

  • Regions draining into a common body of water.

  • Influenced by terrain, soil, and vegetation, affecting runoff and infiltration rates.

Impact of Human Activities

  • Agriculture, urbanization, and deforestation affect water quality.

  • Examples of benefits provided by estuaries include habitat and economic value.

Effects of Nutrient Pollution

  • Caused by excessive nitrogen and phosphorus, leading to eutrophication in water bodies.

  • Turbidity is a measure of the level of particles such as sediment, plankton, or organic by-products, in a body of water. As the turbidity of water increases, it becomes denser and less clear due to a higher concentration of these light-blocking particles.

4.5 Atmosphere

Learning Objectives & Gas Composition

  • Structure: Composed of major gases such as nitrogen (N2), oxygen (O2), and carbon dioxide (CO2).

  • Layer Characteristics: Exosphere, Thermosphere, Mesosphere, Stratosphere, Troposphere defined by temperature changes.

Temperature Gradient in Layers

  • Inverse relationship noted in temperature and altitude.

  • Troposphere holds most gaseous mass due to pressure layers above, impacting weather.

4.6 Global Wind Patterns

Objectives & Key Processes

  • Air Properties: Warm air rises, cool air sinks, leading to precipitation patterns.

  • Coriolis Effect: Deflects moving air currents based on Earth's rotation.

Wind Patterns Impacts

  • Winds at various latitudes influence ocean currents and precipitation.

  • Trade winds and westerlies define climate zones and ecosystems.

4.7 Solar Radiation & Earth’s Seasons

Overview of Solar Effects

  • Insolation: Varies based on latitude, seasons, and angle.

  • Higher insolation observed at the equator.

Effects of Earth's Tilt and Orbit

  • Changes in sun angle with season facilitate temperature variations and precipitation changes.

4.8 Earth's Geography & Climate

Climate Influencing Factors

  • Geography, weather patterns, and soil type define local climates.

  • Rain shadow effects due to elevation and geographic barriers.

4.9 El Niño & La Niña

Understanding ENSO

  • El Niño: Warmer oceanic surface influences global weather patterns.

  • La Niña: Cooling phase leading to varied weather effects.

Environmental Problems

  • Effects of El Niño and La Niña on rainfall, temperatures, and weather events.