GSOC Interpretive Hike at Silver Falls State Park
by Janet Rasmussen
On Saturday, July 11, 2009, Clay Kelleher led an interpretive hike through Silver Creek Falls State Park near Silverton, Oregon. Sixteen members of the Geological Society of the Oregon Country (GSOC) showed up in the morning, but Carol and Sue brought a dog along, not realizing that dogs are not allowed on the main trail. So Carol, Sue, and dog hiked other parts of the park, and we were reunited with them at the end. They also joined us for drinks later in Silverton. Doug volunteered to shuttle a car to the far end of the park, planning to run back to the starting point to join us. That didn't work out. He ran back ok, but we hadn't even started yet. So after running hither and yon for over 2 hours looking for us, he gave up and returned to the car in the north parking lot. Too bad I had his lunch! Jean Hunt dropped off Taylor and drove her car to the north end too, since she wasn't up to hiking the whole distance. Therefore, we had twelve people hiking the trail.
Bart and Clay at the picnic table, where we had a brief introduction to the geology of the park. A few of us saw a pileated woodpecker on a tree nearby.
After a side trip up a service road to examine the surface geology, the Miocene-aged Fern Ridge tuff, we hiked along the south fork of Silver Creek before it goes over South Falls. The streambed is the very flat top of Grande Ronde basalt flow, about 15.3 million years old.
At the top of South Falls
The group admiring South Falls. Most of the big falls come down over a basalt ledge that is undercut like this one. When I first came here as a kid, that was the most exciting part, to walk behind the waterfalls! The reason for the ledges being undercut is that there are several layers of basalt laid down at intervals of several hundred thousands of years. During those long periods, soils developed and plants grew. The thin layers of buried soils are more easily eroded than the basalt, and also conduct groundwater, which leads to more rapid erosion.
Clay is explaining the geology of the falls region to the group as we walk along.
People on the trail are dwarfed under the falls.
Underneath the falls are intriguing holes in the rock. These are called "erosional chimneys", formed by water trickling down through cracks in the rock. As it freezes and thaws, it breaks off bits of rock over time. Bart and Betty Lou are eying these holes, and I thought if I were a kid again, I'd be climbing up there.
No problem, Bart goes for it.
In one of the other undercuts, we saw a wall of maidenhair ferns growing.
Lower South Falls.
I enjoyed taking photos from unusual angles. You can't take a bad picture in this place, everything is so beautiful.
I liked this reflection as we crossed one of the bridge gratings. It was a perfect day for a hike.
The stream is clear and beautiful.
Lower North Falls is more like a water slide. There were 10 falls that are named on this trail, the smallest being Frenchie Falls. It's only a trickle, really. Since there are larger falls without names, Clay categorizes these in frenchie units, as a "two frenchie" sized falls, etc. He also pondered over what constitutes a waterfall, officially? The distance it falls or the amount of water? Must the stream of water fall freely, and if so, is Lower North Falls really a waterfall?
Middle North Falls had pounded out a deep plunge pool below.
At last we made it to North Falls. It was nearly 2 in the afternoon, and I was worried about Doug, who hadn't had any lunch. The trail we had walked was about 4.6 miles long, and of course there are no restrooms along it. So some of us were well motivated to keep moving along.
Still, the old soil layer here was interesting, and we stopped to have a look at it as well as the round holes up in the ceiling of the overhang, where trees were standing before the red hot lava poured over them. In the foreground are Larry, Dave, Betty Lou, Clay, and Julia.
We rendevouzed with Doug and Jean at the North Falls parking area. I gave Doug his lunch and went to stand in line for the facilities. Clay said there was one more falls to see, and so we all walked the short distance down to Upper North Falls. By now, the parking lots were full and many people were enjoying the area. We bumped into Carol and Sue, and let them know we planned to stop in Silverton for refreshments. Clay and Dave elected to walk back to their cars via the Rim Trail, another 2 miles or so. Everyone else crammed into our car and Jean's, and rode back to the South parking lot to retrieve cars.
In Silverton, we found a nice tavern with a sunny deck overlooking Silver Creek, and enjoyed liquid refreshments before heading for home. A good time had by all!
My thanks to trip leader Clay for helping me to identify the waterfall photos and with editorial assistance.
