Redcloud Cliff
21. Redcloud Cliff dominates this view of the east wall of the caldera (Panorama I). The Redcloud Cliff flow of rhyodacite lava fills the V-shaped vent crater from which it issued. This flow and its kin (unit re; ~27 ka), the Grouse Hill flow and dome and a small dome above Steel Bay (Panorama E), were emplaced when thick glacial ice was present on Mount Mazama. Also prominent are the cliff-forming lava (unit dc; 715 ka, weighted mean) and pumice-fall deposit (unit dcp) of dacite of Pumice Castle beneath the Redcloud Cliff flow. Below these are comparatively thin andesite of Applegate Peak (unit aa; ca. 210-270 ka), the lava shield of andesite of Cloudcap Bay (unit ac; est. 28710 ka, weighted mean), pyroclastic flows and lava of dacite of Sentinel Rock (unit dr; 3366 ka here), and andesite of Kerr Notch (unit ak; ~340 ka here). Dikes of units dr (at right end of Panorama I), ac, aa, and dc cut units older than their respective extrusive equivalents. Climactic pumice fall (unit cp) and proximal ignimbrite (unit cb) are found at the caldera rim, but Wineglass Welded Tuff (unit cw) is absent except for a small outcrop at a low point to the right of photo.
Photograph by Charles R. Bacon.