The Palisades
20. Aerial view of northeast caldera wall (Panorama H). The Palisades, the tall cliff above talus in center, is the ice-bounded lava flow, andesite of Roundtop (unit ar; 15913 ka), that rests on thick glacial till and fluvial deposits largely obscured by talus. Below the lake surface, these permeable deposits rest on glaciated andesite of Cloudcap Bay (unit ac); seepage through these deposits apparently prevented Crater Lake from filling significantly higher than present elevation (Bacon and others, 2002). To the right of the Palisades is the scree chute known as the Wineglass. The bowl of the glass is scree from the three Holocene pumice-fall deposits (units rhp and cp) and the overlying Wineglass Welded Tuff and proximal ignimbrite (units cw and cb, respectively); the stem of the glass crosses subglacial and subaerial andesite of Applegate Peak (unit aa; ca. 210-270 ka) lying on glacial till obscured by talus. The cliff at the caldera rim to the right of the Wineglass is ice-bounded andesite of Grotto Cove (unit agc; 7410 ka here). On the left end of the panorama, the Palisade flow (Williams, 1942) forms a cliff that reaches the lakeshore (unit dpe; 1119 ka), fills a glacial paleovalley to the left of Roundtop, and is overlain by glacial till, the Holocene pumice-fall deposits, Wineglass Welded Tuff that thickens to the right toward the topographic low point on the rim, and proximal ignimbrite. Walker Rim, approximately the northeastern distal limit of climactic ignimbrite, is visible in the distance 46 km beyond the Wineglass.
Photograph by Charles R. Bacon.