Formed Soils are developed from mineral and organic matter and generally contain an active population of organisms. Unlike solid rock, soils are full of pores and channels that serve to conduct air and water. Each type of soil expresses characteristics of the parent material from which it developed and reflects changes imposed by its surrounding environment. Five major influences on soil formation include the nature of the original parent material, weathering, climate, land surface features, and the action of plants and animals. These factors determine the physical and chemical properties of various kinds of soil.
Parent material is the basic mineral and organic material from which the soil is formed.
Alluvial materials are deposited by rivers and provide rich productive deltas, floodplains, and terraces. Lacustrine deposits, formed in lakes, were later exposed by receding glaciers. Marine deposits occur along the margins of most oceans and gulfs. During the last Ice Age, huge continental ice sheets moved across much of Northern Europe, Asia, and North America. Their enormous weight crushed and transported material that later served as parent material for soil.