Major reorganization of the Snake River modulated by passage of the Yellowstone Hotspot

The details and mechanisms for Neogene river reorganization in the U.S. Pacific Northwest northern Rocky Mountains have been debated over a century with key implications how tectonic volcanic systems modulate topographic development. To evaluate paleo-drainage networks, we produced an expansive data set provenance analysis of detrital zircon U-Pb ages from Miocene to Pleistocene fluvial strata along proposed proto-Snake Columbia River pathways. Statistical comparisons Miocene-Pliocene spectra do not support previously hypothesized drainage routes Snake River. We use unmixing models test prior against newly route, which circumnavigated entered Basin northeast incision Hells Canyon. Our ancestral route best matches age throughout region. Furthermore, this northerly satisfies provides context shifts sedimentology fish faunal assemblages western Plain through Miocene−Pliocene time. posit that eastward migration Yellowstone Hotspot its effect on thermally induced buoyancy uplift, coupled densification eastern lithosphere, are primary were isolated one another until early Pliocene. Following basin integration, substantial increase area likely overtopped bedrock threshold contained Lake Idaho, led Canyon establishment modern network.