gley formation

• • limited vegetation produces a thin mor humus and low temperatures cause low decomposition
• • heavy precipitation causes waterlogging, flat relief causes drainage problems, impermeable clay can impede drainage
• • waterlogged soil creates anaerobic conditions, iron compounds change from red to blue as oxygen is extracted by micro organisms
• • cold temperatures and water logging mean few biota survive
• • limited biota reduces mixing resulting in distinct layers
• • burrowing animals leave oxygen pockets allowing re-oxygenation of the iron in the soil creating red mottling
• • shallow roots limit materials being recycled
• • freeze thaw causes vertical mixing causing large rock chunks to be brought up to A and B horizon