It is highly probable that in the synclinal formation of the Cañon City Embayment, the east side, at least, developed as a monocline. Its west limb was down-warped to form half of the syncline, and its east limb was up-warped as Cooper Mountain was elevated. The developing monocline was steep with high westward dips. Tensional forces must have developed in the upper bend and westward compressional forces in the lower bend. In some portions of the monocline the compression exceeded the tensile strength of the rocks; thus the Fourmile Creek Thrust Fault and associated tear faults were formed as the more mobile and active upper parts of the fold slid over the lower. The effects of thrusting are now seen as thinned and overturned beds adjacent to the faults, and characterized by the products of dislocation metamorphism that developed in the zone of intense deformation and dislocation along the sole of the overthrust fault, and in the zones of the tear faults.
Proceedings of the Iowa Academy of Science
©1959 Iowa Academy of Science, Inc.
Marshall, George L.
"The Related Faults of the East Side of the Cañon City Embayment, Colorado,"
Proceedings of the Iowa Academy of Science, 66(1), 328-333.
Available at: https://scholarworks.uni.edu/pias/vol66/iss1/45