Warner Range in the northeast corner of California
August 11, 2023
Because of its remote location far from urban centers, the Warner Mountain Range is relatively unknown. We have thought about visiting this place, and exploring its volcanic rocks, for many years. We knew about the Warners because my husband Jay traveled through them on the way to his geologic field site in the Black Rock Desert in northwestern Nevada (see map below). He worked there in the 1980s as an employee of the U.S. Geological Survey. We finally got a chance to visit during a backpacking trip with three others on August 2–5. It was a relatively easy trip to make—just over three hours—now that we live in Ashland, Oregon. When living in San Francisco it would have taken us seven hours.
Geologic setting of the Warner Mountains
These volcanic rocks are not part of the modern Cascade Range or the Yellowstone Hot Spot migration track. Rather, they are related to an earlier version of the Cascades, when the oceanic plate that was subducting beneath North America steepened and volcanism resumed in this area. Previously, a shallow-dipping oceanic plate had caused subduction-related volcanism to cease and move mountain building eastward to the present-day Rocky Mountains, an event called the Laramide Orogeny.
We traveled east from Ashland and stopped at Alturas for lunch—see map at top of page. From there, we made a quick stop at an obsidian mine (see section below) and then continued to the Pepperdine Trailhead where we camped overnight. The trailhead is located just north of the “M” in Mountains on the map above.
According to our maps, a trail called the Upper Cottonwood Trail connects to the Owl Creek Trail that extends north–south along the east side of the Warner Range at a lower elevation than the Summit Trail. The trail no longer connects because of deferred maintenance, but it did get us down into delightful meadows and an area of hoodoos below our camp on the east side.
While in Alturas, on the way to the Pepperdine Trailhead, we stopped at the Modoc National Forest Service office to inquire about trails in the Warner Range. Although staff didn’t provide much information about the trails, they did inform us about local obsidian mine sites where collection was permitted. Since we had a few extra hours that day, we proceeded a short distance north to the Middle Fork Davis Creek site after obtaining a free collecting permit from the forest service office.
Ponce, et al., 2009, Geophysical Studies in the Vicinity of the Warner Mountains and Surprise Valley, Northeast California, Northwest Nevada, and Southern Oregon: U.S. Geological Survey Open-file Report 2009-1157. (https://pubs.er.usgs.gov/publication/ofr20091157)