DETRITAL ZIRCON PROVENANCE AND PALEOGEOGRAPHIC TRENDS FOR PENNSYLVANIAN AND TRIASSIC SEDIMENTARY ROCKS IN SOUTHWESTERN WYOMING AND NORTHERN UTAH-COLORADO
Age populations present in samples include 2420–3500 Ma (primary source: Wyoming province), 1810–2015 Ma (cratonic suture belts), 1535–1810 Ma (Yavapai-Mazatzal provinces), 1300–1535 Ma (mid-continent anorogenic granites), 900–1300 Ma (Grenville orogen), 510–725 Ma (accreted peri-Gondwonan terranes) and 285–510 Ma (Appalachian orogen). Overall age distributions in all samples are consistent with transcontinental drainage networks recycling Paleozoic meta-sedimentary rocks in the central Appalachian region. Spectra from the Pennsylvanian Weber Ss. from CO and UT are nearly identical, however, the inferred age-correlative Tensleep Ss. in WY has a more peaked Appalachian source at 434 Ma, as well as a significantly higher proportion of 900–1300 Ma detrital zircons. This suggests a slightly different source region for the fluvial system that supplied detritus to form the Tensleep Ss. aeolianites in WY, potentially including sourcing of Grenville-age plutons.
The Early Triassic Dinwoody Fm. in the Uinta Mountains is similar in provenance to the Tensleep and Weber sandstones, yet has a greater proportion of <700 Ma detrital zircon grains. The Dinwoody Fm. from Red Canyon, WY, contains a markedly higher proportion (~28%) of >2420 Ma detrital zircon grains derived from the Wyoming Province, suggesting that a local source for grains of this age may have been exposed during Dinwoody Fm. depositional time.