Earth Science Concepts and Processes

Posted on May 9, 2024 in Geology

Glaciers and Ice Formations

Glacier Types

  • Ice Sheets: Extensive, continental-scale ice masses.
  • Ice Caps: Smaller, circular ice masses that bury the landscape.
  • Ice Fields: Elongated ice masses across mountain ranges.
  • Piedmont Glaciers: Glaciers that spread out as they leave valleys.
  • Tidal Glaciers: Glaciers that meet the sea.
  • Continental Glaciers: Massive ice sheets covering vast areas.

Glacier Formation

  1. Snow survives summer and accumulates.
  2. Snow compresses air spaces between ice crystals.
  3. Slow process over thousands of years.

Glacial Mass Balance

Comparison between ice gains and losses. Equilibrium occurs when accumulation equals ablation.

Glacier Movement

  • Basal Slip: Slow sliding of the glacier on meltwater.
  • Crevasses: Vertical cracks in glacial ice due to complex terrain.

Glacial Features

  • Supraglacial Lakes: Meltwater lakes on the glacier surface.
  • Moulins: Vertical conduits in the ice for water drainage.

Permafrost

Soil or rock remaining below 0°C for 2+ years.

  • Active Layer: Melts each year.
  • Talik: Unfrozen ground below permafrost.
  • Ice Wedge: Ice formation due to freeze-thaw expansion.

Geological Processes

Stress and Strain

  • Tension: Stretching due to extension.
  • Compression: Shortening due to compression.
  • Shear: Twisting and tearing from transform forces.
  • Strain: How rocks respond to stress.

Folding and Faulting

  • Folding: Bending of rock layers.
  • Faulting: Breaking of rock layers.

Geological Structures

  • Dome: Oldest strata at the center.
  • Anticline: Upward fold.
  • Basin: Downward fold.
  • Syncline: Downward fold.

Earthquakes

  • Epicenter: Location on Earth’s surface where earthquake occurs.
  • Focus: Location within Earth where earthquake originates.
  • Body Waves: Travel through Earth.
  • Surface Waves: Travel along Earth’s surface.

Volcanoes

Eruption Types

  • Hawaiian: Effusive, non-explosive.
  • Ultraplinian/Super Eruptions: Extremely large and explosive.

Volcanic Products

  • Pyroclasts: Ash, lapilli, bombs, and blocks.

Supervolcanoes

Eruptions with a magnitude of 8 or higher.

Consequences of Super Eruptions

  • Acid rain
  • Vegetation destruction
  • Global cooling
  • Increased cancer risk
  • Longer winters

Eruption Triggers

  • Magma-water interaction
  • Decompression
  • Earthquakes
  • Sea level fall

Phreatic and Phreatomagmatic Eruptions

  • Phreatic: Explosive expansion of water.
  • Phreatomagmatic: Explosion from water-magma interaction.

Submarine Lava Flows

  • Pillow Lavas: Small, rounded lava formations.
  • Lobate Flows: Larger, lobed lava formations.
  • Lava Sheets: Extensive, sheet-like lava flows.
  • Peperite: Lava intrusions into wet sediments.

Erosion and Deposition

Erosion Processes

  • Deflation: Wind removal of loose particles.
  • Abrasion: Sandblasting effect of wind-blown particles.

Desert Landforms

  • Playa: Temporary lake bed.
  • Arroyo: Dry streambed.
  • Alluvial Fan: Fan-shaped sediment deposit.
  • Bajada: Broad slope formed by merging alluvial fans.

Climate and Climate Change

Natural Climate Influences

  • Continental position and topography
  • Atmospheric gases and aerosols
  • Volcanic activity
  • Solar variability
  • Milankovitch Cycles: Long-term changes in Earth’s orbit and tilt.

Climate Patterns

  • El Niño: Warming of waters in the eastern Pacific.
  • La Niña: Cooling of waters in the eastern Pacific.
  • PDO (Pacific Decadal Oscillation): Affects the North Pacific region.
  • NAO (North Atlantic Oscillation): Affects North Atlantic region.
  • AO (Arctic Oscillation): Affects Arctic region.

Groundwater

Aquifer Properties

  • Storage: Ability to store water.
  • Porosity: Volume of open spaces.
  • Permeability: Ability to transmit water.

Groundwater Depletion

  • Cone of Depression: Lowering of water table near a pumping well.
  • Drawdown: Decline in water level.
  • Groundwater Mining: Overpumping beyond aquifer recharge.

Weather and Atmospheric Processes

Lifting Mechanisms

  • Convergent Lifting: Low pressure zones.
  • Convectional Lifting: Local heating.
  • Orographic Lifting: Air forced over mountains.
  • Frontal Lifting: Collision of air masses.

Cyclogenesis

Formation and development of cyclones.

  • Open Stage: Beginning of rotation.
  • Occluded Stage: Cold front overtakes warm front.
  • Dissolving Stage: Cyclone weakens.

Winter Storms

  • Blizzards: Snowstorms with strong winds and blowing snow.
  • Ice Storms: Freezing rain causing ice accumulation.

Rivers and Fluvial Processes

River Channel Features

  • Undercut Bank: Erosion on the outside of a bend.
  • Point Bar: Deposition on the inside of a bend.

Angle of Repose

Steepest stable angle before material slumps.

Mass Movements

Types of Mass Movements

  • Fall: Rockfall
  • Slide: Landslide, slump
  • Flow: Earthflow, mudflow
  • Creep: Slow downhill movement of soil.

Water Properties

  • Polarity: Electric charge causing attraction and repulsion.
  • Hydrogen Bonding: Bonding between water molecules.

Atmospheric Stability

  • MAR/SAR (Moist/Saturated Adiabatic Lapse Rate): Rate of temperature change with altitude in moist air.
  • DAR (Dry Adiabatic Lapse Rate): Rate of temperature change with altitude in dry air.

Winds

Forces Affecting Wind

  • Gravitational Force: Increasing air pressure.
  • Pressure Gradient Force: Generates wind.
  • Coriolis Force: Deflective force causing wind curvature.
  • Frictional Force: Drag on winds.

Atmospheric Circulation

  • Rossby Waves: Protrusions of the polar front.
  • Jet Stream: Concentrated band of wind.