UPb detrital zircon and ⁴⁰Ar³⁹Ar detrital sanidine dating of paleoriver deposits refines the timing of the mid-Cenozoic drainage reversal from NE- to SW-flowing rivers across the southern edge of the Colorado Plateau. NE-flowing paleorivers of the Mogollon Rim Formation were of multiple ages: ≤59.38 Ma for the Flying V outcrop and ≤37–33 Ma for other outcrops. These NE-flowing paleorivers were defeated by construction of the 38–23 Ma Mogollon–Datil volcanic field and extensional collapse of the Mogollon Highlands. The 37.6–21.8 Ma Whitetail Conglomerate of the Salt River paleocanyon records the transition from NE-flowing rivers to internal drainage that persisted from 30 to 14.67 Ma during continued extensional collapse. The SW-flowing proto-Salt River was established by about 12 Ma and flowed into Tonto Basin ~7 Ma. The Salt River extended its length to near Phoenix via basin spillover from the Tonto and Verde basins about 2.8 Ma and became established in its present path only in the past ~500 ka. Between 3.0 and 0.52 Ma, incision rates of the Salt River's headwaters have been steady at 95 m/Ma as calculated using the age and height of four far-traveled basalt runouts from the Springerville volcanic field. These incision rates contrast with 10 m/Ma rates for downstream areas near the Sentinel-Arlington volcanic field on the Gila River over the past 2.37 Ma. This 85 m/Ma of differential incision was a geomorphic response of headwater drainages to changes in base level (base level fall plus headwater uplift) that, at least in part, was a consequence of top-down integration of the Salt and Verde river systems via spillover. Neogene headwater uplift is proposed to have set the stage for and perhaps driven this downward integration by increasing river gradients, and progressive uplift in the past 3 Ma may help explain post-integration steady headwater incision. Surface uplift components include construction of the Springerville and San Francisco volcanic fields and related mantle-driven epeirogenic uplift of the southern rim of the Colorado Plateau. Long-term differential incision rates for the Salt River (85 m/Ma) are less than for the Colorado River system (140 m/Ma across Grand Canyon) suggesting west-up neotectonic tilting of the Colorado Plateau.

U Pb 碎屑锆石和⁴⁰ Ar ³⁹古河流沉积物的 Ar 碎屑 sanidine 测年细化了中新生代排水系统从 NE 流向 SW 流经科罗拉多高原南部边缘的河流逆转的时间。Mogollon Rim 组NE 向流的古河具有多个时代：飞V 露头≤59.38 Ma，其他露头≤37-33 Ma。这些 NE 流动的古河流被 38-23 Ma Mogollon-Datil 火山场的建造和 Mogollon 高地的伸展塌陷打败了。盐河古峡谷的 37.6-21.8 Ma Whitetail 砾岩记录了从 NE 流动的河流到内部排水系统的转变，在持续的伸展塌陷期间持续了 30 到 14.67 Ma。西南流的原盐河大约在 12 Ma 左右建立，并流入 Tonto 盆地~7 Ma。盐河通过大约 2.8 Ma 的 Tonto 和 Verde 盆地的盆地溢出将其长度延伸到凤凰城附近，并且仅在过去的约 500 ka 中才建立在目前的路径上。在 3.0 到 0.52 Ma 之间，根据 Springerville 火山场四次远距离移动玄武岩流的年龄和高度计算，盐河源头的切割速率一直稳定在 95 m/Ma。这些切割速率与过去 2.37 Ma 期间希拉河上 Sentinel-Arlington 火山区附近下游地区的 10 m/Ma 速率形成对比。这个 85 m/Ma 的差异切口是源头排水系统对基线变化（基线下降加上源头上升）的地貌响应，至少部分是盐河和佛得河系统自上而下整合的结果通过溢出。新近系水源抬升被认为是通过增加河流梯度为这种向下整合奠定了基础，并且可能通过增加河流梯度来推动这种向下整合，过去 3 Ma 的逐步抬升可能有助于解释整合后稳定的源头切口。地表隆起部分包括 Springerville 和 San Francisco 火山区的建造以及科罗拉多高原南缘的相关地幔驱动的表生隆起。盐河的长期差异切割速率 (85 m/Ma) 低于科罗拉多河系统（横跨大峡谷的 140 m/Ma），表明科罗拉多高原新构造向西倾斜。地表隆起部分包括 Springerville 和 San Francisco 火山区的建设以及科罗拉多高原南缘的相关地幔驱动的上表成因隆起。盐河的长期差异切割速率 (85 m/Ma) 低于科罗拉多河系统（横跨大峡谷的 140 m/Ma），表明科罗拉多高原向西新构造倾斜。地表隆起部分包括 Springerville 和 San Francisco 火山区的建设以及科罗拉多高原南缘的相关地幔驱动的上表成因隆起。盐河的长期差异切割速率 (85 m/Ma) 低于科罗拉多河系统（横跨大峡谷的 140 m/Ma），表明科罗拉多高原向西新构造倾斜。