Surface 13: Periglacial Landscapes

Periglacial landscapes (define + significance)

• areas adjacent to glaciers or ice sheets

• in cold climates and freeze-thaw cycles

• exhibit unique landforms and processes influenced by frost action and permafrost

Permafrost (define + influence)

• ground that remains frozen for at least 2 consecutive years

• affects soil stability, drainage patterns, and the formation of unique landforms like ice wedges and pingos

Frost heave

• the upward movement of soil due to freezing of water within it

• can lead to the formation of features like frost mounds and patterned ground

Solifluction

• slow, downhill movement of waterlogged soil in periglacial environments

• shapes landscapes by creating features like solifluction lobes and terraces

Pingos

• ice cored mounds that form when water freezes and expands in the ground

• common in periglacial areas and can grow to significant sizes

Patterned ground

• geometric patterns like polygons, stripes, and circles

• form due to freeze-thaw cycles and the sorting of soil and rocks

Types of periglacial slopes + characteristics

• gelifluction slopes → shaped by the flow of waterlogged soil

• blockfields → areas covered with angular rock fragments

• talus slopes → accumulations of rock debris at the base of cliffs

Thermokarst (formation + effects)

• forms when permafrost thaws l

• effects: collapse of the ground surface + formation of depressions, lakes, uneven terrain

Human impact on periglacial landscapes

• construction, mining, climate change

• disrupts permafrost, increases erosion, alters drainage patterns

Role of vegetation in periglacial landscapes

• helps stabilize soil

• reduces erosion

• insulate the ground from temp. fluctuations

  • influencing the distribution of permafrost and landforms