Stratigraphic Dating of Fault Systems

Several northeast-trending transverse faults cut the Purcell succession and parts of the Lower Paleozoic succession in the Hughes Range. Relationships along unconfonnities within and at the base of the Lower Paleozoic strata provide evidence of the natilre and timing of displacement on these faults. Field mapping of the faults and unconformities hounding three Lower Paleozoic formntions have been the main focus of tliis study. The Lussier Creek fault trends north for most of its length, but at the !south end of the Hughes Range swings northeast, parallel to the transverse faults in the Purcell anticlinorium. Tow'ards the Rocky Mountain Trench, the fault merges wirh an old transverse fault, the Boulder Creek fault (Figure 1-2-1 ).