The Lewis thrust fault is one of the major tectonic elements developed during late Cretaceous to early Tertiary time in the southern Canadian Rocky Mountains, and is often cited as a classic example to illustrate thrust geometry and kinematics. Mapping initiated by USGS to update the geology of Glacier National Park prematurely ended due to budget constraints, however, the discovery of considerable structural complexity provided the basis for this research. Possible development of a duplex fault zone developed by out-of-sequence thrusting will be investigated by structural mapping, and subsequent study of kinematic indicators. Results will allow accurate documentation of geometric relationships between the faults of the Lewis system leading to a full re-evaluation of the history of this important example of a major thrust.
