What is the primary composition of Residuum parent material?

The primary composition of Residuum parent material is weathered bedrock. Residuum is formed in place through the weathering process of the underlying bedrock, where the rock gradually breaks down into smaller particles due to natural processes such as temperature changes, water, and biological activity. This results in a soil layer that directly reflects the characteristics of the bedrock, including its mineral composition and structure.

In contrast, other types of parent materials like alluvium or colluvium are transported materials, which is not the case for residuum. Understanding this distinction is vital in soil science, as it influences the soil's properties, such as its texture, fertility, and drainage capabilities.