The initiation of thick-skinned deformation in orogen forelands causes major changes to topography and subsidence with implications for sediment dispersal. We investigated such effects using new detrital zircon U-Pb age data for provenance analyses of the Eocene Claron Formation, deposited in the Laramide foreland of southern Utah. Detrital zircon U-Pb ages from the Claron Formation indicate spatially and temporally heterogeneous provenance. Most samples are dominated by 1100 Ma, 1400 Ma, and 1700 Ma age peaks associated with the Sevier thrust wedge, while the other samples show similar age distributions to Cretaceous foreland strata, suggesting recycling from Laramide uplifts on the basin margin. We assess the implications of Claron Formation provenance for sediment dispersal across the Utah Laramide foreland using a new structure contour compilation that reveals the geometry of Laramide uplifts and basins. The compilation shows that the Claron Formation was deposited in a structural basin bounded by the Sevier orogen and the Kaibab, Circle Cliffs, and Monument Uplifts, consistent with the detrital zircon age data. Published stable isotope data from the Claron Formation reflect internal drainage, suggesting that the Claron basin was the terminal sink for sediment in this area. These relationships suggest that the California River, a hypothesized Eocene axial paleoriver through the Laramide foreland with distinct provenance from the Claron Formation, did not flow through this area as previously hypothesized. Comparison with Cretaceous drainage networks underscores that Laramide foreland partitioning disrupted older axial drainage networks and established more localized drainage networks that resulted in heterogeneous sediment provenance.
Tye et al. (Wed,) studied this question.