Last week I had the opportunity to travel to Glide, OR. and see my partner’s family. Glide is located in the Umpqua Valley of Southern Oregon and, in my opinion, has some of the best geology the state has to offer. I realize I’m making a tall statement when the Columbia River Gorge, Mt. Hood, and the John Day Fossil Beds (just to name a few) reside within the state boundaries. However, I love this part of the state because a lot of it resides on what used to be the ocean floor. Thanks to uplift and erosion (either man made or river cut), that ocean floor can be seen at the surface. And with some help from fellow geo tweep, Ron Schott, I was able to learn more about the geology of the area.
Glide basically lies at the foot of the Western Cascades on what was probably Oregon’s old coast line. Most of the rocks are from the Eocene era (~30-50 mya) and are composed primarily of basalt and sedimentary rocks.
Interestingly enough these same basalt flows are roughly the same age as the Clarno Formation of central Oregon.
Both of these images are of the same out crop exposed at the road cut in Glide. I can’t get into the details of the geology too much because, quite frankly, I don’t understand it well enough to offer up a sound explanation, but I’m working on it.