剖面层ABC土壤剖面层中深度排第三的剖面层，不受风化的影响，由上两层及其他矿物组成的母岩所构成 The third-deepest soil zone in ABC soil, unaltered by weathering and made up of the parent rock from which the two uppermost layers derive as well as other mineral materials.
侵蚀，风化，风蚀受日晒雨淋的岩石发生特征的变化甚至崩溃的过程中的任何一化学或物理变化 Any of the chemical or mechanical processes by which rocks exposed to the weather undergo changes in character and break down.
岩石经风吹雨打而剥蚀，直至完全风化。 Rocks weather until they are worn away.
