I'm not sure. If you look at a map of Idaho you an see a long volcanic scar across the southern part of the state called the Snake River Plain. It's a huge jumble of basaltic lava flows and the location of the other-worldly Craters of the Moon National Monument. Current theory suggests it's the result of the American plate moving westward over the Yellowstone Hot Spot (which remains stationary.) It's a process that seems to be continuing.
Oregon and the West Coast in general have seen plenty of volcanic action and it's going to continue. I have a hunch the sunstone region is more likely the result of volcanism related to subduction of the Pacific Plate under the American plate. Subducted rock forms magma chambers resulting in active volcanoes like the Three Sisters at Bend, Mt. St. Helen's, etc., extending south to Lassen and Shasta in California and all the way to the tip of Chile.
We're lucky to live in a time when those Ring of Fire volcanoes are relatively inactive. Think of what it would have been like if we'd been around when the Columbia Plateau Flood Basalts were forming! Columbia Plateau
Nope; wouldn’t be the Hot Spot. McDermitt Caldera is the one I was thinking of, but that is over 100 miles east of Lakeview; about 175 miles ESE of the sunstone fields in that link. That entire region is volcanic, one way or another.
And, no; I would not have wanted to be anywhere even half way near any flood flows. We had andesite flows in the Medford area, most notably visible as Upper & Lower Table Rock.
We used to drive across central & south eastern Oregon a lot. The state/counties have pits where they dig, screen, & stockpile red lava gravel, mainly for ‘sanding’ the roads in winter. Those deserted pits also make decent ‘pit stops’, during some of which we picked up a life time supply of bath-grade grey pumice stones.
Loved our visit to Craters of the Moon.