Wedge uplifts occur widely in nature and provide critical information as to the processes responsible for mountain building, because they yield data regarding the manner of application of tangential forces and regarding the competence and response characteristics of the materials undergoing compression.
The larger wedge uplifts occur at several orders of magnitude and apparently are essentially coincident in size and outline with granitoid batholithic masses which have “headed” as they approached the surface, thus giving, upon cooling, massive rock units with the shape of a downward-pointing wedge. Under compression the more yielding country rock is forced beneath the sloping flanks of these wedges, causing them to be elevated straight up, if the slope of the sides be the same, or as a tilted wedge uplift if the sides of the plutons have different dips. The kite-shaped Beartooth massif (uplift) of Montana and Wyoming is one such basement wedge uplift, and the Owl Creek Range of Wyoming includes a similar but smaller feature, having a slightly inclined top. The northern segment of the Bighorn Mountain uplift is of similar character.
Another, subsidiary type of wedge uplift is characteristic of strongly folded competent sedimentary units included within more yielding strata, as at Turner Valley, in Alberta, where an early phase of forward overthrusting eventually gives rise to back thrusts, thus defining wedges which have been elevated by underpinching.