QS Study

Parent Material: Soil forming factor

Parent material is a passive control factor in soil formation. Parent materials can be any in-situ or on-site weathered rock debris (residual soils) or transported deposits (transported soils). Soil formation depends upon the texture (sizes of debris) and structure (disposition of individual grains/particles of debris) as well as the mineral and chemical composition of the rock debris/deposits. Soils form in parent material that is not just bedrock weathered in place. Parent material is classified based on its mode of transportation: ice, water, gravity, wind, lakes, and oceans, or in place. Parent material transported by ice is known as glacial till.

Nature and rate of weathering and depth of weathering mantle are the important consideration of parent materials. There may be differences in soil over similar bedrock and dissimilar bedrocks may have similar soils above them. But when soils are very young and have not matured these show strong links with the type of parent rock. Also, in case of some limestone areas, where the weathering processes are specific and peculiar, soils will show a dear relation with the parent rock.