Blocklike uplift of Precambrian metamorphic rocks during Laramide deformation resulted in the formation of an asymmetric faulted mountain mass extending south from the central Bighorn unit.
The internal structure of the metamorphic rocks is dominated by a complex anticline plunging to the north-northwest as demonstrated by foliation, lineation, relationship of minor folds, and distribution of mapped units. The geometry of the fold is elucidated by statistical analysis of the structural elements and tectonic profile construction, which reveal a closed, slightly overturned cylindrical anticline with planar limbs. Measured lineation corresponds to the axial line, as determined from statistical analysis of foliation data, and is, therefore, b-lineation.
Structures in overlying sedimentary rocks resulted from draping over active basement blocks. The blocks are bounded by the Horn and Tensleep faults. The Horn fault parallels foliation in the Precambrian rocks; whereas, the Tensleep fault is a rejuvenated Precambrian fault showing that the structural gram of the basement influenced later deformation.