7a - additional reading

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Ploughing boulders are boulders that move down slope due to frost heave and thaw consolidation.

Controls:

Air temperature - inpacts the freezing of the ground and thermal regime.

Snow cover - provides insulation leading to less freezing and lowering the mobility of ploughing boulders.

Thaw consolidation is controlled by either geothermal heat or pressure melting from the boulder when refreezing of water from snow melt occurs.

Most heave occurs during autumn/early winter

slows down during later winter due to snow cover preventig freeze penetration.

differential ground thermal regime is essential to ploughing boulders because of increased susceptibility to gelifluction beneath the boulder.

Berthling et al. 2001