Formation of Gley soil

humus layer

limited vegetation produces a thin acidic MOR humus

temperature

low temperatures cause a slow rate of decomposition

precipitation/snowmelt

heavy precipitation and snow melt causes waterlogging, resulting in poorly defined layers

relief

found on flat surfaces as relief can cause drainage problems

micro organisms

cold temperatures and waterlogged conditions mean few organisms can survive.

roots

shallow roots limits the recycling of minerals

parent material

parent material is impermeable rock or clays which can impede drainage

iron compounds

waterlogged soil creates anaerobic conditions meaning iron compounds are changed from reddish brown to blue. this is due to oxygen being extracted by microorganisms.

red mottling effect

soil drying out in summer leaves oxygen pockets allowing re-oxygenation of the iron in the soil causing a red mottling effect.

freeze thaw weathering

freeze thaw weathering takes place causing large chunks of angular rock to be brought up to the A and B horizons.