Abstract

Many extensive, smooth, parallel surfaces suggesting water action occur in the blanket sandstone formations with eolian crossbedding of the Colorado Plateau. These planes sharply truncate crossbedding and obviously cannot be of depositional origin; much material has been removed in forming them. The name multiple parallel-truncation bedding planes is proposed. Examples are seen in the Entrada, Navajo, Wingate, De Chelly, and Coconino Sandstones. It is supposed that conditions were frequently such that previously accumulated sand was removed down to the water table, creating the smooth surfaces which now separate intervals of crossbedded sandstone. This process is to be expected in interior basins. Windswept, saturated surfaces such as the Great Salt Lake Desert show similar leveling effects, but here the water table is falling so a stratigraphic record is not preserved.

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