Solifluction
Topic: Geomorphic Processes: Weathering, Mass Movement, Erosion and Soil Formation · NCERT: Class 11, Ch 5 "Geomorphic Processes"
Meaning
Solifluction is the slow downslope flow of soil that is soaked with water. It is a slow flow mass movement, meaning material moving downslope under gravity. It is common in cold regions with permafrost, which is ground that stays frozen all year. In summer only the top layer thaws. Water cannot drain down through the frozen ground below, so the thawed layer becomes soaked and slowly slides over the frozen layer. It also happens in humid temperate regions where surface soil stays soaked for long periods. It leaves lobes and terraces of soil on slopes.
Example
On the tundra slopes of northern Canada and Siberia, the thawed summer soil slowly flows downhill over permafrost. It forms tongue-shaped lobes of soil on the hillsides.
Don't confuse with
- Soil creep: also slow, but it happens in all climates and does not need soaked soil or frozen ground beneath.
- Mudflow: fast and follows stream channels after heavy rain. Solifluction is slow and spreads across the slope.
Related concepts
- Mass movement
- Activating causes of mass movement
- Soil creep
- Mudflow
- Debris avalanche
- Slump
- Rockslide
- Rock fall