Earth Systems and Resources Notes

Unit Overview

  • This unit includes modules on plate tectonics, soil formation, Earth’s atmosphere, solar radiation, global wind patterns, climate, El Niño/La Niña, the greenhouse effect, and global climate change.

A Brief History of Earth

  • Key events: Universe begins (14,000 MYA), Sun forms (5,000 MYA), Earth forms (4,600 MYA), oceans form (4,400 MYA), first life appears (3,500 MYA), plate tectonics begins (3,200 MYA), oxygen increases (2,200 MYA), first land plants (450 MYA), first land animals (400 MYA), dinosaurs (250 MYA), modern humans (1.2 MYA).

Layers of Earth

  • Compositional: Crust (silicates), Mantle (Si-Mg-Fe), Core (Fe-Ni).

  • Mechanical: Lithosphere (rigid), Asthenosphere (plastic), Mesosphere (denser), Outer Core (liquid), Inner Core (solid).

Theory of Plate Tectonics

  • Lithosphere broken into plates floating on asthenosphere; moved by convection currents.

Evidence for Plate Tectonics & Continental Drift

  • Includes continent shapes, mountain ranges, rock/fossil matches, past climates, sea floor spreading, magnetic striping, and modern measurements.

Consequences of Plate Tectonics

  • Influences earthquakes, volcanoes, nutrient recycling, continental motion, global temperatures, biodiversity, mountain formation, and magnetosphere creation.

Plate Boundaries

  • Convergent: Plates collide; crust recycled. Types: Continent-Ocean, Ocean-Ocean, Continent-Continent.

  • Divergent: Plates separate; crust created. Occurs at mid-ocean ridges.

  • Transform: Plates slide past each other; crust neither created nor destroyed.

Volcano & Earthquake Locations

  • Most occur at plate boundaries like the Ring of Fire.

Earthquakes

  • Plates stick, pressure builds, then slip, releasing energy. Epicenter (surface), Focus/Hypocenter (below surface).

Volcanoes

  • Vents where magma escapes. Explosiveness depends on magma viscosity and dissolved gases.

Magma vs. Lava

  • Magma: Below ground. Lava: Above ground.

Pyroclastic Flow

  • Superheated ash moving rapidly down a volcano.

The Three Types of Rocks

  • Igneous: Melts and cools. Extrusive (cools quickly), Intrusive (cools slowly).

  • Sedimentary: Weathered, eroded, deposited, compacted, cemented.

  • Metamorphic: Changed by heat, pressure, chemical change.

Rock Cycle

  • Processes changing rock over time involving heat, uplift, weathering, erosion, transport, compression, melting, and crystallization.

Abundance of Ores & Metals

  • Ores: Concentrated mineral deposits. Reserves: Extractable resource quantity.

Ores & Reserves

  • Ore grade decreases as reserves deplete.

Depletion of Resources

  • Future supply depends on actual supply and rate of use. Depletion time is when 80% is used up.

Economic Depletion

  • Mining becomes too expensive or complicated.

Extracting Minerals from Deposits

Surface Mining

  • Remove overburden. Types: Open-Pit, Strip, Contour Strip, Mountain-Top Removal.

Subsurface Mining

  • Underground in shafts/tunnels. More expensive, less environmental damage.

Effects of Mineral Use

  • All steps use energy and create pollution.

Removing Metals from Ores

  • Causes land disruption, spoils, solid waste, water/air pollution.

External Processes Shape Earth

  • Internal builds up; external wears down.

Physical Weathering

  • Mechanical breakdown of rocks.

Chemical Weathering

  • Dissolving rocks with water, acids, gases.

Erosion

  • Sediment movement from one place to another.

Soil

  • Link between rock cycle and life. Contains air, water, sediments, minerals, organics, and organisms.

  • Dirt: Soil can’t support life.

What Affects Soil Formation?

  • Climate, Relief, Organisms, Parent material.

Soil Formation

  • Starts as inorganic material; organisms add organic matter (humus).

Soil Horizons

  • O, A, E, B, C horizons and Bedrock(R).

Characteristics of Soil

  • Determined by physical, chemical, and biological properties.

Infiltration & Leaching

  • Water moves through soil, dissolving/carrying nutrients.

Physical Properties of Soil

  • Soil Texture: Sand, silt, clay.

  • Porosity: Size of gaps between particles.

  • Permeability: How quickly water infiltrates.

Chemical Properties of Soil

  • Cation Exchange Capacity: Clay's ability to hold positive ions.

  • Base Saturation: Amount of bases neutralizing acidity.

Biological Properties of Soil

  • Microorganisms fix nitrogen.

  • Detritivores break down organic material.

Atmosphere Composition

  • 78% Nitrogen, 21% Oxygen, 1% Argon; also Carbon dioxide, Water vapor, Ozone, Methane.

Layers of the Atmosphere

  • Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere.

The Uneven Heating of Earth

  • Affected by Earth’s tilt, albedo, and insolation.

Earth's Tilt

  • 23.5°. Higher temperatures at equator due to direct sunlight.

Albedo

  • Surface reflectivity. Darker = lower albedo.

Insolation

  • Solar energy received per area and time.

Properties of Air

  • Density, water vapor capacity, adiabatic heating/cooling, latent heat release affect air circulation.

Convection Currents

  • Due to density differences. Warm air rises, cool air sinks.

Hadley Cells

  • 0° to 30°. ITCZ has most intense sunlight.

Ferrell Cells

  • 30° to 60°. Distribute heat.

Polar Cell

  • 60° to 90°. Air cools/sinks at poles.

Effects of Earth's Rotation

  • Coriolis Effect: Wind deflection. Right (N. Hemi.), Left (S. Hemi.).

Global Wind Patterns

  • Consistent air movement; causes ocean currents.

Basic Wind Belts & Calm Areas

  • Polar Easterlies, Westerlies, Trade Winds; Polar Front, Horse Latitudes, ITCZ/Doldrums.

Effects of Topography

  • Mountains cause rain shadows.

Climatograms

  • Temperature and precipitation graph.

Ocean Currents

  • Density/Thermohaline: Temp. and salinity driven, slow.

  • Surface: Wind-driven, fast.

Gyres

  • Closed circular currents caused by continents and Coriolis.

Upwelling

  • Wind blows away from land.