Preston E. Hotz 1973 <p>Blueschist is plentiful in the Yreka-Fort Jones area,&nbsp;eastern Klamath Mountains, adjacent to a belt of serpentinite that&nbsp;marks the boundary between two fundamental lithologic units, an&nbsp;eastern belt of early Paleozoic sedimentary and metamorphic rocks, and&nbsp;a western greenstone-chert assemblage of late Paleozoic and Triassic(?)&nbsp;age. The blueschists, which contain lawsonite and glaucophane or&nbsp;crossite, occur with phyllitic quartzite and siliceous phyllite of the&nbsp;Stuart Fork Formation, which is overthrust northwestward on the&nbsp;greenstone-chert terrane. The blueschist facies metamorphism probably&nbsp;was synchronous with Middle and Late Jurassic metamorphism of the&nbsp;Stuart Fork Formation. The blueschist-serpentinite terrane possibly&nbsp;marks the site of collision between the eastern Klamath plate and an&nbsp;oceanic western Paleozoic and Triassic plate.</p> application/pdf en U.S. Geological Survey Blueschist metamorphism in the Yreka-Fort Jones area, Klamath Mountains, California article