Blended unconformity

An unconformity having no distinct surface of separation or sharp contact, as at an erosion surface that was originally covered by a thick residual soil, which graded downward into the underlying rocks and was partly incorporated in the overlying rocks; e.g., a nonconformity between granite and overlying basal arkosic sediments derived as a product of its disintegration. Syn: graded unconformity

Source: Dictionary of Mining, Mineral, and Related Terms