Glaciation key terms

Features of periglacial land (4)

Cold environments, permafrost, low summer precipitation, slow nutrient cycle.

Nivation

Seasonal snow in hollows encourages frost weathering, forming nivation hollows.

What is frost heave

Ice expansion in soil causes surface distortion and soil/rock movement.

What is solifluction

Slow downslope flow of saturated soil in periglacial regions after surface thawing.

How are ice wedges formed

Water infiltrates permafrost cracks, expands (frost action), forming ice wedges.

How is patterned ground formed

Repetitive freeze-thaw cycles create patterns like circles, stripes, or polygons.

How are pingos formed

Groundwater pushed up by freezing forms a dome-shaped mound.

How are loesses formed

Silt-sized particles carried by wind accumulate in layers.

What is fluvioglacial

Processes involving rivers and glaciers; sediment transport and deposition.

What is moulin

A shaft in a glacier that drains meltwater.

What is a crevasse

A deep crack in a glacier due to movement and stress.

What is hydrostatic pressure

Fluid pressure at equilibrium due to gravity, affecting ice dynamics.

What is cavitation

Vapor cavities form in liquid due to pressure drop, causing damage upon collapse.

What is a kame terrace

Ridge of glacial deposits between a glacier and valley walls.

What is a kame

Mound of glacial debris in a depression or at glacier's edge.

What is an esker

Long, winding ridge of sediments deposited by a glacier.

What is proglacial

Area in front of a glacier where sediment and ice melt interact.

What are sandurs

Glacial outwash plains formed by meltwater streams.

What are proglacial lakes

Lakes formed in front of a glacier from meltwater and sediment.

What are meltwater channels

Streams carrying meltwater from glaciers.

what are kettleholes

Depressions from melted ice blocks left by retreating glaciers.

What is stratification

Layering of sediments, water, or ice in glacial environments.

What is imbrication

Alignment of sedimentary particles due to water flow.

How do kames form

Sediment deposition in melting glaciers forms mounds or hills.

How are eskers formed

Meltwater streams deposit sediment under glaciers, forming ridges.

How are kame tunnels formed

Meltwater runs under a glacier, deposits sediment; channel fills as ice retreats.

What is a varve

Sedimentary layer representing a year of deposition in glacial lakes.

How are varves formed

Seasonal sediment deposition creates distinct layers in glacial lakes.

Outwash plains

Flat areas of stratified sediments from glacial meltwater.

What are overflow channels

Channels formed when rivers overflow, transporting sediment and water.

What is fracture and traction

Breaking of rocks (fracture); sediment rolling along a water body (traction).

What is dilation

Fractures parallel to erosion surfaces as bedrock adjusts after overlying material is removed.

`what is meltwater erosion

Meltwater erodes landscape, transporting sediments.

Macro-scale

Landform over 1km in size.

Meso scale

Landform between 10m and 1km.

micro scale

Landform roughly less than 5km.

icehouse conditions

Very cold glacial conditions.

Greenhouse conditions

Warmer interglacial conditions.

Pleistocene

2mil-11700 years ago. Glacial ice covered higher and middle latitudes.

Stadials

Conditions lead to ice readvance.

Interstadials

Conditions lead to ice withdrawal.

What is orbital/astronomical forcing

Changes in solar energy reaching Earth force climate change.

What is calving

Ice sheet breaks at glacier snout, forming icebergs.

What is thermohaline circulation

Ocean circulation driven by temperature and salinity differences, distributing heat.