Abstract

Stratigraphic analysis of the Kirkman Formation indicates the presence of sedimentary and tectonic breccia deposits. These breccias were produced by three different mechanisms. Breccias, that contain intraclasts of laminated limestone in a silty micrite matrix were produced as storm surge deposits or by turbidites along the margin of the Oquirrh Basin during the transition between deposition in the Oquirrh Basin and deposition on the Central Utah Shelf during the early Permian Period. Limestone that has been fractured by faulting and subsequently recemented with sparry calcite cement are breccias that were produced as the result of deformation of the Kirkman Formation during the Laramide Orogeny in the late Cretaceous and early Tertiary Periods. These breccia deposits are associated with thrust faults and folds that have increased the thickness of the stratigraphic section in areas such as Kirkman Hollow in Hobble Creek Canyon east of Springville, Utah, and the northwest Oquirrh Mountains near Tooele, Utah. The last type of breccia, in the Kirkman Formation, was produced as the result of dissolution. Dissolution of the Kirkman Formation has produced circular- and lens-shaped deposits of breccia cemented with sparry calcite cement. Dissolution occurred during the late Cretaceous and early Tertiary Periods following the Laramide Orogeny, during the formation of the Basin and Range Province during the late Tertiary and Quaternary periods, and during the present erosional cycle. The above three breccia types have been used to differentiate the Kirkman Formation from the underlying Oquirrh Group and the overlying Diamond Creek Sandstone.