What does the term "till" refer to in soil classification?

In soil classification, the term "till" refers to a type of glacial sediment that is typically unsorted and unstratified. It is formed by the direct deposition of material from glacial ice as it melts, which results in a mix of particle sizes ranging from fine silt to large boulders. Unlike sorted sediments, which have been reworked by water or wind and exhibit a specific order in particle size and distribution, till contains a jumble of materials that have not been arranged in a systematic manner. This unique characteristic is essential in differentiating till from other types of sediments, contributing to its definition and role in various soil classifications.

Thus, understanding that till is a result of glacial activity and is characterized by its unsorted nature is crucial in soil classification and the study of soil horizons. The other terms mentioned do not accurately capture the essence of till as it is recognized in soil science.