| The Upper Triassic Chinle Formation exposed in the Wolverine Petrified Wood area of the Grand Staircase-Escalante National Monument, southern Utah, preserves interbedded siltstone, sandstone, conglomerate, and paleosols representing a floodplain dominated environment. Deposition was seasonal, and sediment was deposited episodically, allowing sufficient subaerial exposure for the deposits to undergo pedogenesis. Deposition was interrupted by four major and two minor periods of erosion resulting in the development of sequence boundaries. Fossils are rare and occur predominantly in the sandstone beds that overlie the sequence boundaries, indicating that sedimentation rates were high following erosional events. Petrographic and paleocurrent data suggest that the sediment source for most of the formation remained constant, and that the sediment was derived from the south and east. Paleosols changed from Vertisols, in the lower to middle part of the formation, to Aridisols near the top of the formation. This change is inferred to indicate an increasingly arid climate. |
