Anthropogenic impact on sediment transfer in the upper Missouri River catchment detected by detrital zircon analysis

Abstract Downstream sediment transport in river systems is impacted by anthropogenic modifications, such as dams or levees. This study used detrital zircon U-Pb geochronology and mixture modeling to investigate the effects of on provenance signatures along upper Missouri Yellowstone Rivers. The River longest dam-free North America, while has several major reservoir-forming dams. We present 4777 new individual ages from 32 sand samples collected bars Yellow-stone Rivers their tributaries. These data track downstream modification age due sequestration reservoirs, bank erosion, mixing at stream confluences. In contrast, evolve more progressively River, which displays less influence muted tributary dilution. component proportions extensively dammed vary up 27% downstream, with amplified changes occurring confluences dramatic are attributed storage preferential capture heavy minerals (including zircon) resulting a reduced load Consequently, models show disproportionate contribution tributaries compared trunk Dams not only reduce flux but also change locations where generated initiating erosion dam.