What term describes soil that is mainly unweathered bedrock?

The term that describes soil that is mainly unweathered bedrock is bedrock. Bedrock refers to the solid rock that lies beneath the soil and is not significantly altered by weathering processes. It serves as the foundation for soil formation and is the layer from which various soil types develop over time through processes like erosion, weathering, and biological activity.

Other types of soil, such as topsoil and subsoil, consist of weathered materials and organic matter, which are critical for plant growth and support various ecosystems. The term horizon refers to different layers within the soil profile, each with distinct characteristics. However, bedrock stands out as it remains in its natural, unweathered state, directly underlying these other layers.