Detrital zircon geochronologic study of upper Paleozoic strata in the eastern Klamath terrane, northern California

U-Pb analyses have been conducted on individual detrital zircon grains from Upper Devonian(?)-Carboniferous strata of the Bragdon Formation and Upper Carboniferous-L ower Permian strata of the Baird Formation. These are the two most important clastic units in the Redding section of the eastern Klamath terrane of northern California. There are 31 grains from the Bragdon Formation that yield mainly concordant to slightly discordant ages ranging from ca. 363 Ma to ca. 3.12 Ga. Grains with ages of ca. 363-572 Ma in this sample were apparently shed primarily from the nearby Trinity complex, which contains igneous rocks of these ages. Older grains, ranging from 1.07 to 3.12 Ga, but mostly between 1.76 and 1.99 Ga, were likely recycled from lower Paleozoic strata of the Yreka terrane or the Roberts Mountains allochthon. Six detrital zircons from the Baird Formation are all apparently concordant, with interpreted ages between 320 and 326 Ma. These grains are locally derived and probably record igneous activity represented by the widespread volcanic and volcaniclastic rocks within the Baird Formation.