Dating lava light
They are also strikingly similar to lava flows exposed at the Abert Rim, a spectacular fault scarp some 760 meters (2,490 feet) high, located 10–15 miles southwest of the Rabbit Basin sunstone localities.Gunn and Watkins (1970) proposed that these lavas are part of the same volcanic episode, and that their feldspar phenocrysts might even have originated in the same magma chamber.
We spent three days there before driving three hours southwest to spend the next two days at the Dust Devil and Sunstone Butte mines.
These deposits are referred to in the literature as the Lakeview, Lake County, Plush, or Rabbit Basin occurrences.
In eastern Oregon, sunstone occurs as basalt flows (see figure 4).
Sunstone occurrences (×) are linked to the local eruptive center of these basalts, Steens Mountain (SM) and Abert Rim (AR).
As the basalts ebbed, new volcanic forces kindled a hot spot in the earth’s mantle, spawning volcanic calderas (C) across Idaho’s Snake River Plain (SRP) to the Yellowstone supervolcano (Y).