McKenzie Pass Geology Field Trip
September 18, 2004
William Orr, retired professor of geology was our guest instructor. At McKenzie Ranger Station we viewed the large relief map in the foyer. Bill pointed out lava flows, cinder cones and glaciated valleys.
On our journey upriver we viewed roadside glacial moraines. At the mouth of Lost Creek, Ice Age, lakebed deposits or “varves” are exposed along the trail. The alternate dark and light bands represent different seasons.
At Limberlost Campground giant Chinook salmon rested in shallow, spring-fed pools. Aquifers formed by relatively recent lava flows maintain an even, year-round flow of pure water resulting in the finest quality, salmon-spawning beds in the Willamette basin.
Near McKenzie Pass we stopped to study a lava flow and adjacent glacial striations on bed rock. Abruptly light rain turned to snow and wind. We retreated down the mountain for a final stop at Lost Creek Spring.
I’d like to thank Dr. Orr for taking the time to join us to teach Cascade Range geology. Participants were Max Brown, Rob Castleberry, Joyce Thomas, Marriner Orum, Nola Shurtleff and trip organizer Dave Predeek.