Glaciation Flashcards
(6 cards)
What are the Milankovitch Cycles?
Eccentricity: Changes in the Earth’s orbit from circular to elliptical over ~100,000 years.
Obliquity: Variations in the Earth’s axial tilt between 21.5° and 24.5° over ~41,000 years.
Precession: The wobble of the Earth’s axis, altering the timing of seasons over ~21,000 years.
These cycles influence the Earth’s climate and are linked to glacial and interglacial periods.
How do warm-based and cold-based glaciers differ?
Warm-based glaciers: Found in temperate regions; basal temperatures at or above the pressure melting point, allowing basal sliding and significant erosion.
Cold-based glaciers: Found in polar regions; basal temperatures below the pressure melting point, resulting in limited movement and erosion.
What are key periglacial processes?
Frost heave: Expansion of soil due to ice formation.
Solifluction: Slow, downslope flow of water-saturated soil.
Nivation: Erosion under snow patches leading to hollow formation.
Pingos: Ice-cored hills formed by groundwater freezing.
What landforms result from glacial deposition?
Moraines: Accumulations of debris deposited by glaciers.
Drumlins: Streamlined hills composed of glacial till.
Eskers: Long, winding ridges formed by subglacial meltwater streams.
Kettle holes: Depressions left by melting ice blocks in outwash plains
What are common glacial landforms created by erosion?
Cirques (Corries): Bowl-shaped depressions on mountainsides.
Arêtes: Sharp ridges between adjacent cirques.
U-shaped valleys: Formed by glacier movement, characterized by steep sides and flat bottoms.
Hanging valleys: Smaller valleys that join the main glacial valley at a higher elevation.
