On Monday, September 15, I had the privilege of taking Paul Hammond, a geologist, down the White Salmon River. Hammond had a mission of sampling different rocks from the canyon of the White Salmon from the BZ Corners section to the town of Husum. His goal is mapping out the different lava flows that make up the canyon that we, at Wet Planet, get to raft through. The section of water that is roughly five miles long took us close to six hours to raft, as we stopped very frequently to gather samples when it appeared that the lava-rock was from a different ancient lava flow. Paul brought along his trusty assistant Steve, who has a love for geology as well and is good with rock hammer for getting those samples.
This was quite a unique opportunity for me to learn something new about this canyon that I have been down hundreds of times. Either by asking questions, listening to Paul and Steve talk or by having one of them explain what they where finding, although their true results will be confirmed by lab results, what I gathered is that the lava rock that makes up the canyon is old, very old. And, actually, some of it is new, well in geologic terms that is, new being about 25,000 to 30,000 years and old being around 12 to 15 million years old.
Some of the oldest rock they found was from the Columbia River Basalt which came from a flow originating on the border of Oregon and Idaho.
That particular flow showcased some deposits of well rounded rock worn down by countless years in a river bed. And then there were other flows that made up most of the flows we encountered, coming from areas of the Indian Heaven Wilderness, around Mt. Adams, such as Lemei Rock which was the origin of a lava flow and also there was a flow that originated from the Ice Caves area up around Troutlake.
Not hard to believe, but not knowing prior to the trip, often lava flows are named from the area of their source. I also learned that the flow of the river has changed course many times, due to different lava flows that came in and either caused the river to change direction or by filling up the river bed entirely to make the river erode away a completely new path through the lava.
The section of the White Salmon River we sampled has a gradient of about 100 ft per mile, much greater than I had thought.
Geologist Paul Hammond recording data about Canyon on Wet Planet Raft on White Salmon River.
All in all it was pretty cool experience to takes theses guys down the river. Not only did I learn a few things about the river, I also found a new respect for the river canyon that I spend a lot of time in. In addition, it was nice to take the time to stop off so many times, to get those rock samples, and appreciate a canyon that is easy to take for granted when you travel down it almost every day of the summer. I will defiantly have to say that I will never look at the river in exactly the same way.
Thanks, Paul and Steve and to the study of geology, and also to Wet Planet for this rare opportunity.
-Hootie, Wet Planet Raft Guide appreciationg this river canyon since 2003 …
– Jaco @ 06:12 PM
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