19. Aerial view of Cleetwood Cove, looking northwest from above Palisade Point (Panorama G). Boat landing and lake gauge (gaging station) at left; Palisade Point at right. Holocene rhyodacite of the Cleetwood flow (Williams, 1942; unit rh) forms cliff at caldera rim above the arcuate cove; tongue of lava descending to lake edge is rhyodacite of the Cleetwood flow, remobilized from the pasty interior of the lava flow after the caldera collapsed. This and other evidence indicates that the Cleetwood flow was emplaced shortly before the climactic eruption, probably at most a few years earlier. Scalloped form of Cleetwood Cove is typical of topographic walls of collapse calderas that enlarge beyond the bounds of a subsiding central block by landsliding during and immediately following a caldera-forming eruption. In the caldera wall beneath the Cleetwood flow are near-vent, pumice-fall deposits from the onset of the Cleetwood eruption lying on pumice from the Llao Rock vent (collectively unit rhp here), underlain by andesite of Grotto Cove (unit agc; 71±5 ka) and andesite of the boat landing (unit abl; 102±10 ka). Trail to the boat landing traverses partly welded Wineglass Welded Tuff (unit cw), then descends forested scree slope on thick climactic pumice fall with interbedded nonwelded pyroclastic flows (unit cp), approximately 1-m thickness each of Cleetwood and Llao Rock pumice falls, and glacial till before dropping through and along base of the unit abl lava flow. Units visible in middle distance beyond caldera rim are forested northeast portion of the Grouse Hill rhyodacite flow (unit re; ~27 ka), Pumice Desert (unit cf), and Timber Crater shield volcano (unit atc; 137±10 ka). Mounts Bailey and Thielsen are to left and right, respectively, of Diamond Lake in the distance.
Photograph by Charles R. Bacon.