Revised Lithostratigraphy of the Sonsela Member (Chinle Formation Upper Triassic) in the Southern Part of Petrified Forest National Park Arizona

摘要

BackgroundRecent revisions to the Sonsela Member of the Chinle Formation in Petrified Forest National Park have presented a three-part lithostratigraphic model based on unconventional correlations of sandstone beds. As a vertebrate faunal transition is recorded within this stratigraphic interval, these correlations, and the purported existence of a depositional hiatus (the Tr-4 unconformity) at about the same level, must be carefully re-examined.