The Giant Steps of Bug Creek, Richardson Mountains, N.W.T., Canada

ABSTRACTThis paper describes large steps developed in sandstones of the Jurassic Bug Creek Formation on a5km long plateau in the Richardson Mountains, Northwest Territories, Canada. Except for the stepsatop the plateau, the planar portion or tread of each step abuts a riser or a scarp at its upper end and ablock barricade at its lower end. The weathering of bedrock and blocks supplies fine sediments thatcover the surface of the treads. The thickness of the surficial cover appears to be less than 120cm.According to nine 14 C dates, thesediments areHolocene in age.Thisstudystresses two features of thegiant steps: subterranean drainage and the presence of block barricades. It is proposed: (1) thatsubterranean drainage plays an important role in the preservation of block barricades; and (2) that thegiant steps can evolve into cryoplanation terraces if the block barricades are destroyed by erosion.Copyright # 2006 John Wiley & Sons, Ltd. KEY WORDS : giant step; cryoplanation terrace; sedimentology; Richardson Mountains; Ogilvie Mountains