In addition to places where plates separate or come together, in other places, plates grind past one another on great faults called transform faults. There, narrow basins filled with sediments may occur, with or without volcanic rocks, and the bedrock typically is sheared and fractured by the fault movement in zones up to several kilometres wide. Although such faults leave little in the rock record in the way of great volumes of sedimentary or igneous rock, they may record the movement of great tracts of crust, and the rearrangement of the geography of continents and ocean basins.

The best known transform fault is the seismically active San Andreas Fault in California, which separates the North American Plate from a small continental fragment in southwestern California and Baja California attached to the north-moving Pacific Plate. The analogous structure at British Columbia latitudes is the submerged Queen Charlotte Fault north of Vancouver Island and west of the Queen Charlotte Islands, and extending into southern Alaska.

Ancient transform faults in the Canadian Cordillera are the Tintina and Northern Rocky Mountain trench faults in the Yukon and northeastern British Columbia, and the Fraser Fault, whose eroded trace forms the Fraser Canyon, east of Vancouver. These faults moved from 100 to 35 million years ago, when western parts of the Canadian Cordillera were partly coupled to northward moving oceanic plates, in a manner analogous to modern southwest California.