Looking south from the western edge of the Upper Klamath valley at the Mountain Lakes Wilderness with Mount Harriman forming the high point. With the exception of the one high point the region looks like a relatively flat plateau or given the proximity to Crater Lake National Park, one may think that due to the topographic similarity between the two regions, that they may in fact share a similar geologic origin.
Picture a volcano not all that different from present-day Mount Hood outside of Portland centered on the location of the Crater Lake. Similar to the Mount St. Helens series of eruptions in 1980, the upper portion of the Mount Mazama edifice was removed during intense volcanic activity that led to the areas subsequent collapse during rapid and violent extrusion of pyroclastic flows, one of the most dangerous of all volcanic events. Annie Creek canyon on the south side of Crater Lake is a great spot to see and examine the nature of a pyroclastic flow; the Pinnacles is also a great spot.
South from the western edge of the Upper Klamath valley at the Mountain Lakes Wilderness with Mount Harriman forming the high point.
Taken from along the Fort Klamath road that connects Oregon state route 140 with 62. Notice the broad U-shaped bowl feature; it is indicative of glacial activity. Extending northward towards the photographer is Tomahawk Ridge, a series of cinder and scoria cones. Mount Harriman is the high point on the left (east) with Greylock and Crater Peaks forming the two highest points, respectively, on the right (west).
Taken from the west looking east, from Surveyor Mountain detailing the western margin of the Mountain Lakes Wilderness.
Looking from Doaks Mountain which is east of Mountain Lakes. Highest point is Aspen Butte whose summit is 820X feet high with Little Aspen Butte being the second dominant structure, located on the south-facing slope.
Little Aspen Butte at higher elevation with Clover Butte visible at lower elevation.
Close-up of the glacial carved out summit region of Aspen Butte with the arrow focused on the exposed conduit of this 470,000 year old composite volcano. Glacial erosion, primarily headward erosion of an alpine glacier producing a cirque basin, has etched out the vertically oriented volcanic conduit.
Well-developed platy jointing in an Aspen Butte lava flow; produces a shale-like bedding fissility characteristic of clastic sedimentary rocks.