Detrital zircon U-Pb provenance of the Colorado River: A 5 m.y. record of incision into cover strata overlying the Colorado Plateau and adjacent regions

摘要: New detrital zircon U-Pb age distributions from 49 late Cenozoic sandstones and Holocene sands (49 samples, n = 3922) record the arrival of extra-regional early Pliocene Colorado River sediment at Grand Wash (western USA) downstream locations ca. 5.3 Ma subsequent evolution river’s provenance signature. We define reference for (n 559) 601). The river is distinguished by (1) a higher proportion Yavapai-Mazatzal derived Rocky Mountain basement uplifts relative to Grenville Mesozoic supra crustal rocks, (2) distinctive (∼6%) Eocene–Oligocene (40–23 Ma) reworked basins volcanic fields in southern Mountains and/or eastern Green catchment. Geologic relationships interpretation 135 published throughout catchment provide interpretative basis modeling Mixture based upon modified formulation Kolmogorov-Smirnov statistic indicate subtle yet robust change signature over past 5 m.y. During this interval contribution strata decreased ∼75% 50% while pre-Cretaceous increased ∼25% 50%. interpret reflect progressive erosional incision into plateau cover strata. Our finding consistent with geologic thermochronologic studies that maximum post–10 erosion was concentrated across Utah–western region.