Structural geology of the eastern Richardson Mountains, Yukon and Northwest Territories: Some field observations and a note of caution for palinspastic reconstructions

The Richardson anticlinorium is a major tectonic feature marking the eastern limit of the Cordilleran orogen in northern Yukon and Northwest Territories. Limited structural observations on the eastern flank of the Richardson anticlinorium indicate that the strain intensity increases significantly close to major faults that are associated with deformation zones tens to hundreds of metres wide. A predominant dextral sense of motion is documented for several major faults belonging to the Richardson fault array. However, second-order features exhibit highly variable kinematics. In several cases, strike-slip faults cut shallower dipping faults and follow steep bedding planes, suggesting that dextral motion occurred in a previously deformed and tilted sedimentary succession. The amount of displacement along the Richardson fault array is poorly constrained. Further investigation is warranted as potential large displacements may bear significant consequences on palinspastic reconstructions.