The concept of tectonic denudation followed by deposition of lower middle Eocene Wapiti Formation volcanic rocks on the exposed Heart Mountain detachment has been challenged by Hauge. His "extending allochthon' interpretation requires that the Wapiti Formation be fault emplaced and that lineations in a volcanic tuff overlying the fault north of Jim Smith Peak be fault striae in "microbreccia'. Our re-examination of the field evidence in minute detail indicates that these lineations were produced by flowage of volcanic rocks on a thin layer of air-fall tuff. The evidence indicates that this tuff was deposited on the detachment surface during the brief interval that the denuded surface was exposed. -from Authors
Additional publication details
Heart Mountain, Wyoming, detachment lineations: are they in microbreccia or in volcanic tuff?