A Reverse Fault Interpretation of Rattlesnake Mountain Anticline, Big Horn Basin, Wyoming

Abstract

Rattlesnake Mountain anticline near Cody, Wyoming, is considered to be a classic "drape fold" by many geologists. Such an interpretation is at odds with the many compressional features known to exist throughout the fore/and. Certain problems in published drape fold cross sections suggest that other models should be considered. The interpretation presented here includes all the basic observations shown in published drape fold interpretations from adjacent areas plus observations of basement configuration on the down-faulted block. These observations are then interpreted within constraints of the concept of local structural balance. The resulting interpretation is one of a structure controlled by a reverse fault inferred to flatten toward the east. This structurally balanced cross section demonstrates that Rattlesnake Mountain anticline is part of the same family of compressional, reverse-faulted structures displaying major mountain overhangs such as the Casper arch and Wind River Mountains.