イスクット‐ウヌク川丘群

Eight small basaltic centers at the southern end of the Stikine volcanic belt near the Alaska border comprise the Iskut-Unuk River Cones group. Lava flows date back 70,000 years, but the subaerial vents produced cinder cones and lava flows that were probably all active between about 9,000 and a few hundred years ago. Five of the centers produced lava flows that traveled up to ~20 km down the Iskut and Unuk River valleys and their tributaries. The three remaining centers are products of ice-contact volcanism that formed pillow lava, hyaloclastite breccias, and scoria. The flows are similar in mineralogy and contain abundant crustal xenoliths. Vents in the Iskut River Canyon area produced at least 10 lava flows, and the Lava Fork vents at least three lava flows, the latest of which erupted within the past few hundred years.