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Figure 4a. Interpretative dip geologic cross-sections across the Alberta thrust belt and potentially the Colorado Front Range, indicating that as the main ranges rose, secondary front ranges also rose. These massive uplifts may have interacted with the basement, releasing magma and energy to the evolving front ranges (Enkin et al., 2000 and discussion with William B. Hansen, independent petroleum geologist, Great Falls, Montana, 14 September 2007).  CL = coastline. 

Figure 4b. Advancing Sigsbee salt wedge and overlying salt-floored basin of coastal plain, continental shelf, and slope sediments interact with the basement uplift, Sigsbee ridge, releasing energy and causing/influencing the salt to “ricochet” off the basement.  Scale in km.