Welcoming 2024 on Songer Butte, Ashland

Happy 2024—may we greet its challenges with peace and optimism. And what better way to bring in the new year, and focus on the positives, than to get out into nature. This post will highlight some of the geologic features that are visible from Songer Butte, where our Ashland Hiking Group went on New Years Day. Songer Butte is located south of Ashland, Oregon, adjacent to Emigrant Lake, the water visible in the background.

Our Ashland hiking group on top of Songer Butte. The view is toward to northwest along Bear Creek Valley that joins the Rogue River Valley farther north, near Medford.
This view is westward across Bear Creek Valley to the Klamath Mountains. The Bear Creek Valley is a valley because it is underlain by mudstone that is very weak and easily eroded. The mudstone is Cretaceous Hornbrook Formation (Kh) that was formed when this region was under ocean water about 100 million years ago. All of the layers are tilting to the northeast, so rocks are older to the west.

The Ashland pluton is granitic rock that intruded into what is now the Klamath terrane about 160 million years ago. Granite is a much tougher rock than mudstone, so it forms a prominent ridge to the west. Rocks are younger toward the northeast—the contact between the Hornbrook Fm (Kh) and the overlying Payne Cliff Fm (Tpc) is at the base of Songer Butte where I am standing to take the photo. A little piece of the butte’s sandstone is labeled Tpc in the lower right corner.
This view is toward the north, showing the eastern side of the Bear Creek Valley. I am still standing on Songer Butte, which is underlain by the Payne Cliff Formation (Tpc). These rocks formed about 40 million years ago, when stream channels meandered westward across a mostly planar surface. Songer Butte is elevated like the other buttes labeled Tpc because these parts of the formation consist of sandstone and conglomerate deposited in stream channels. These sediments are much more resistant to erosion than the adjacent mudstone that formed in floodplains between the channels. If you look carefully, you can see sandstone at the top of the buttes. The mudstone underlies the grassy parts beneath the sandstone and between the buttes.

About 35 million years ago, volcanoes of the Western Cascades (Tv) emitted lava and ash that covered the underlying sedimentary rocks. Grizzly Peak, the treed top of the ridge with Tv label, was then a volcano. Around 15–10 million years ago, volcanism ceased and compression tilted all of the layers to the northeast. Volcanism later resumed farther east, where the active Cascade Range is now located. The closest Cascade Volcano is Mt McLoughlin, that is not visible behind Grizzly Peak. Here is a link to my 2016 post about this volcano: https://landscapes-revealed.net/climbing-mount-mcloughlin-one-of-the-lesser-known-cascade-volcanoes/.
This view is toward the south from Songer Butte. The Siskiyou Mountains, including the prominent peak of Pilot Rock, are along the skyline. Jay is tilting his hand to mimic the northeast tilt of the sandstone and conglomerate layers of the Payne Cliff Formation.

I intend to remind readers that the landscapes around us are a function of the underlying rock types. Ashland lies in a valley with ridges to the northeast and southwest. The high elevation areas are underlain by rocks that are resistant to erosion and the low elevation areas are underlain by rocks that are easily eroded—they are not resistant. If you’d like to learn more about this region, please see the four blogs I posted for my local geology course in 2020, when we all had to start teaching our courses via zoom, including those of us teaching adult education courses. Here is the link to the first blog post: https://landscapes-revealed.net/the-rogue-valley-region-in-sw-oregon-displaying-300-million-years-of-geologic-time/. The subsequent three posts were on April 25, May 2, and May 10 of 2020.

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2 Comments

  1. Mary on January 21, 2024 at 6:16 pm

    Drove out there but no idea where the trail starts. Is it on old green springs rd or past it on 66?

    • Landscapes Revealed on February 2, 2024 at 5:20 pm

      Sorry for delayed response! You take 66 around the lake, past where old 99 joins from the south, then look for Songer Wayside on your left, where there is a parking lot next to the trailhead. Be aware that you need to follow the path by an arm of the lake because there is private property uphill. Near the end of the point there are trails that go uphill to Songer Butte. Good luck Mary!

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