Continent-wide drainage reorganization in North America driven by mantle flow

Abstract

North America (NA) experienced pronounced changes in continental-scale drainage characterized by a reversal for much of the continental interior from north into the Canadian arctic to south into the Gulf of Mexico (GoM) from the Mid-Cretaceous to the Paleocene. However, the driving mechanism for these profound drainage reorganizations remain unexplained. Here, we investigate the role of mantle flow on landscape evolution, by coupling dynamic topography with surface processes. This approach enables us to simulate catchment dynamics and the rearrangement of sediment transport in response to mantle flow. We show that a west-to-east drainage reversal can be induced by the NA overriding the subducted Farallon plate. Moreover, augmented dynamic subsidence caused by a basalt-to-eclogite transformation of an oceanic plateau within the Farallon slab, depressed the GoM region and expanded the integrated drainage to the GoM since the Early Paleocene. For the first time, we show that dynamic topography can explain the north-to-south continental-scale drainage reorganization in North America.