Permian and Triassic Paleogeography of the Eastern Klamath Arc and Eastern Hayfork Subduction Complex, Klamath Mountains, California: Evidence from Lithotectonic Associations and Detrital Zircon

Middle Permian and Middle Triassic volcanic-hypabyssal intrusive complexes form ensimatic arc deposits in the eastern Klamath terrane. Sedimentary matrix melange with blocks of sandstone, chert, and Tethyan fauna-bearing limestone compose the westward-lying eastern Hayfork terrane. Limestone olistoliths were derived from seamounts and incorporated into a subduction complex that was active during the Late Triassic and perhaps as early as the Permian. Geologic and biogeographic relations have previously been interpreted to imply a genetic relation between an ensimatic arc and subduction complex, constraining Permian(?)-Triassic subduction as eastward dipping.