In the Rocky Mountain foreland, Precambrian basement rocks were deformed during Late Cretaceous and early Tertiary time in ways which allowed the Phanerozoic sedimentary cover rocks to be folded over them. The nature of the mechanical behavior of the basement rocks which allowed them to accommodate the shape of the cover has been a persistent and controversial problem. The objective of this research is to examine several well-exposed basement-cored folds in order to identify the mechanisms active during folding. Methods to be used include field structural mapping, analysis of deformation features on several scales, and measurement of strain. The results may help establish the relative importance of the various geological factors which control the response of the basement rocks to later deformation.
