Dynamic coevolution of valley networks and wrinkle ridges in the Martian highlands: Implications for geologic evolution and paleoclimate

Valley networks and wrinkle ridges are commonly observed in the Martian highlands. Geologic cross-cutting relationships between fluvial and tectonic features provide constraints on their formation sequences and the spatiotemporal evolution of these processes. For example, in central Terra Sabaea, a valley network appears to be affected by a wrinkle ridge. Tributaries are diverted along the ridge front and converge into a single, elevated channel across the ridge, suggesting coevolution between fluvial erosion and wrinkle ridge development. In this work, we systematically examine all intersections between valley networks and wrinkle ridges across the Martian highlands, assessing the relative timing and activity of tectonics and fluvial erosion. We identify 70 intersection sites from previously mapped valley networks and wrinkle ridges. Among them, ~60% exhibit syn- to post-fluvial tectonic modification, as indicated by drainage reorganization and valley profile changes; ~30% record pre-fluvial tectonic activity, and only ~7% show purely post-fluvial tectonic activity. Longitudinal profiles from six syn- to post-fluvial tectonic sites indicate that tectonic uplift produced comparable amounts of deformation during syn-fluvial and post-fluvial periods, with one exception. Erosion efficiency coefficients estimated from the incised valley profiles are similar to those observed in arid climates or in regions underlain by resistant bedrocks on Earth. Our results suggest that the widespread tectonic modification of existing valley networks in the intersection sites may reflect a dynamic coevolution of tectonic and fluvial systems during Mars’ hydrologically active past.