PALEONTOLOGY OF THE CHINLE FORMATION IN THE WOLVERINE PETRIFIED WOOD AREA: AN OVERVIEW

Fossils are present in at least four of the six members of the Chinle Formation exposed in the Wolverine Petrified Wood area of the Grand Staircase-Escalante National Monument. The Chinle Formation at this locality consists of a sequence of interbedded siltstones, sandstones, conglomerates, and paleosols. The members present, from earliest to latest are, the Shinarump Member, Monitor Butte Member, Bluewater Creek Member, Petrified Forest Member, Owl Rock Member, and Rock Point Member. The Shinarump Member includes fragments of carbonized wood preserved in silty lenses in the sandstone-rich member. Carbonized wood also occurs in the Monitor Butte and Bluewater Creek Members which are also rich in carbonized leaves. The Petrified Forest Member contains two fossil bearing beds. The first bed crops out an average of 52.8 meters above the base of the Chinle Formation and preserves large amounts of permineralized wood in sandstone and vertebrate bone fragments in sandstone and conglomerate. The second bed occurs as low as 61.6 and as high as 82.45 meters above the base of the Chinle Formation and preserves limited amounts of permineralized wood. These deposits and fossils are consistent with what has been described in previous studies of the Chinle Formation across the Colorado Plateau and which are generally interpreted to represent a terrestrial fluvial and floodplain environment.