Dynamic Planet Notes

Crystal Structure

Ice has a hexagonal lattice structure impacting its thermal, optical, and mechanical properties.

Anomaly of Water

Ice is less dense than liquid water, allowing it to float and affecting ecosystems.

Density of Ice

Ice has a density of about 0.917 g/cm³ at 0°C, affecting glacial dynamics.

Névé

Granular, compacted snow that retains air pockets, crucial for glacial movement.

Firn

Denser intermediate stage between névé and glacial ice, with a density of 0.30 to 0.83 g/cm³.

Glacial Ice

Final product of snow transformation with density greater than 90%, essential for glacier stability.

Ablation

Processes that reduce glacier mass through melting, sublimation, and calving.

Accumulation

Ice formation from snow accumulation, especially during winter months.

Equilibrium Line

Altitude where accumulation equals ablation; critical for understanding glacier health.

Basal Sliding

Movement of glaciers sliding over bedrock due to meltwater lubrication.

Internal Flow

Movement of glacier ice due to deformation from pressure and temperature.

Cirque

Bowl-shaped depressions at mountain heads where glaciers begin to form.

Hanging Glacier

Glaciers that terminate at cliff faces, appearing to hang above valley floors.

Piedmont Glacier

Glaciers that spread out upon encountering flat plains, forming large lobes.

Ice Stream

Rapidly flowing sections of an ice sheet that behave differently from surrounding ice.

Ice Shelf

Floating extensions of ice sheets resting on ocean surface, influencing sea-level rise.

Ice Rise

Grounded portions of ice shelves that stabilize flow behind them.

Moraines

Accumulations of glacial debris; types include end, recessional, lateral, medial, and ground moraines.

Drumlins

Streamlined hills of till formed beneath glaciers, indicating past flow directions.

Eskers

Winding ridges formed by meltwater streams beneath glaciers.

Erratics

Large boulders transported by glaciers, critical for reconstructing glacial movements.

Tarns

Small lakes formed in cirques, often indicative of glacial history.

Proglacial Lakes

Lakes formed from meltwater accumulation in front of glaciers.

Permafrost

Ground that remains permanently frozen, influencing ecosystems and hydrology.

Pingos

Hill-like formations caused by the freezing and expansion of groundwater in permafrost.

Ice Floe

Large pieces of floating sea ice essential for navigation and ecosystems.

Calving

Process where chunks of ice break off from glaciers, contributing to sea-level rise.

Surface Melt

Melting of glacier surfaces due to atmospheric temperatures, impacting global water systems.

Moulins

Vertical channels in glaciers that facilitate drainage of meltwater.

Milankovitch Cycles

Astronomical cycles affecting Earth's climate and glaciation patterns over thousands of years.

Greenhouse Gases

Atmospheric components altering albedo and influencing glacier melting rates.

Isostatic Effects

Rebound of Earth's crust post ice sheet removal, reshaping landscapes.

Varves

Annual layers of sediment indicating fluctuating climatic conditions.

Altimetry

Method of measuring glacier elevation changes critical for climate studies.

Radar

Technique for assessing ice thickness and internal dynamics of glaciers.

Optical Imagery

Satellite data for monitoring surface changes in glaciers.

Gravimetry

Measurement of gravitational pull changes related to ice mass variations.

Ice Cores

Cylindrical samples from glaciers providing historical climate data through gas and isotope analyses.

Ice Avalanches

Sudden collapses of ice with destructive potential in glacial areas.

Lake Outburst Floods

Rapid water release from glacial lakes, posing risks to nearby communities.

U-shaped Valley

Glacier-formed valley with a flat bottom and steep sides, contrasting with river valleys.

Horns

Peaks formed by the convergence of multiple cirque glaciers, showcasing dramatic erosional processes.

Striations

Scratch marks on bedrock indicating direction of past glacier movement.

Rôche Moutonnée

Asymmetrical hill indicating glacier movement direction, yielding geological information.

Ogives

Alternating bands of ice indicating seasonal variations in glacier motion and history.

Icefalls

Dramatic features created by steep drops in glacier flow, often visually striking.