Fast uplift is considered to produce straight mountain-piedmont junctions, narrow valleys with steep long profiles and faceted spur ridges, whereas slow uplift results in embayed mountain-piedmont junctions, broad valleys with gentle long profiles and strongly degraded spurs (Bull, 1987).
Active fault-generated mountain fronts frequently display triangular or trapezoidal facets (faceted spurs, flatirons) that form due to uplift and dissection of a normal scarp by gullies and whose bases are parallel to the fault trace (Cotton, 1958; Bloom, 1978; Stewart and Hancock, 1990).
The shaping of faceted spurs is thought to result mostly from fluvial erosion concurrent with uplift of the mountain front (Hamblin, 1976; Wallace, 1978) or from gradual backwearing, aided by gravitational mass movements (cf.
The geometry of faceted spurs developed on differentiated bedrock, although controlled primarily by the rate of seismotectonic uplift, is frequently modified by resistance to erosion and structure of the bedrock (cf.
This staircase arrangements of faceted spurs points to at least five episodes of uplift of the SMF footwall, probably starting shortly after 31 Ma, i.e.
Anderson, T.: 1977, Compound faceted spurs and recurrent movement in the Wasatch fault zone, north-central Utah, Brigham Young University Geology Studies, Vol.