Figure 1.
(A) View northeast (looking upstream into Zion Canyon) over the surface of the Sentinel rock avalanche deposit; incised gorge of the Virgin River at far right. Qsd—Sentinel rock avalanche deposits; Qts—sandy talus (see Fig. 2). (B) Rock avalanche deposits exposed by river incision, showing constituent rock types assessed from remote mapping; height of exposure is ~150 m. The upper part of the deposit consists primarily of Navajo Sandstone debris, which is characteristically shattered and compact, while the basal portion of the deposit consists of Kayenta material that has been deformed and tilted but often retains small-scale structure. See Figures 2 and 3 for composition of the source.