Faults involving growth sedimentation displace different beds by different amounts. When a reversal of movement sense occurs on such faults, bedding cutoffs act as a vernier scale, and an immaterial point of no net displacement (“null point”) migrates along the fault trace. Multiple reversals generate multiple null points, but neighboring points migrate in opposite directions and annihilate one another when they meet.
As a field example, we present stratigraphic evidence for fault reversal from the Franklinian Basin, Ellesmere Island. “Backstripping” and recognition of the migrating null point permit sequential restoration of the incremental fault displacements. Failure to recognize fault reversals may lead to underestimates, of orogenic shortening or to misidentification of accommodation folds.