hide
Free keywords:
-
Abstract:
We explore the relative importance of tectonic, geodynamic, and surface processes in driving landscape evolution in Argentine Patagonia using 64 new 10Be exposure ages of fluvial terraces preserved over >250 km along the Shehuén and Santa Cruz rivers (50°S). Terrace ages range from 33 ka to 1.5 Ma and coincide with Patagonian glaciations. We demonstrate that landscapes can respond directly to changes in climate forcing driven by the Mid-Pleistocene Transition: our results reveal a transition to 100-k.y. terrace periodicity, and a transient phase of accelerated incision starting at ca. 1 Ma. A regionally uniform incision rate of 130–180 m Ma−1 since 1 Ma suggests uplift linked to asthenospheric heating in the Patagonian slab window, while transient accelerated incision suggests convective instabilities in a low-viscosity mantle. We establish a temporal link between climate oscillations, fluvial incision, and mantle-driven epeirogenic uplift.
