Today we launch the second major stage of our summer adventure – departing for the UK and Ireland later this evening. But a week ago today, we were in my PhD field area, the McKenzie River watershed in the central Oregon Cascades. Joined by Dana and Lockwood, we had a fabulous day exploring the interplay of water and lava in creating a spectacular landscape and revisiting some of my favorite spots from my PhD years.
My favorite picture of the day comes from Upper Proxy Falls, where snowmelt spilling off a hanging valley forms a high waterfall into a mysterious pool. For no matter how much water tumbles down the falls, the pool never overflows into any stream. Instead, the water sinks through the bottom of the pool into a 1500 year old basaltic andesite lava flow (with a 15,000 year old basalt flow under that). Several miles downvalley, and a 1000 feet lower in elevation, the water from Proxy Falls re-emerges as part of huge a spring. But I love to sit near the pool of Upper Proxy Falls and contemplate the mysteries of water and lava.
For Chris, it was fascinating to see Anne enthusiastically guiding us through the springs and lava flows of her scientific youth, and explaining how the subsurface plumbing system created by ancient lava flows was just as important as what we saw on the surface. But we also made it up the top of the McKenzie pass, where we got a nice view of where a lot of that lava ultimately came from, the volcanoes of the High Cascades.
The lava-dominated landscape reminded me a bit of Hawaii, even if the tectonic setting is totally different. And it was useful to get a good idea of what was lying underneath all the trees at lower altitudes. Check out Lockwood’s blog for some nice panoramas from the same spot.