Today, we watch landscapes change over days, years, and decades. But, how do landscapes evolve over thousands to millions of years? In the field, we can observe and measure sedimentary deposits at different spatial scales — from individual grains to bedforms, bars and lobes, channel belts and distributary networks, and ultimately entire basins.  At each scale, deposits record different processes and, in turn, different timescales of landscape evolution. By integrating observations across these nested scales, we can build more complete pictures of how Earth's landscapes evolve in space and time.

Current/future questions: How did Earth's surface respond to the evolution of land plants? What is the relative role of external forcing (e.g., tectonics and climate) and internal forcing (e.g., channel avulsion and migration) in shaping landscapes?

The ability to quantify ancient channel geometries, flow conditions, and sediment transport conditions from sedimentary deposits is a crucial step to characterize ancient landscape dynamics and. In the field, we can make detailed measurements of channel deposits, and we can apply geomorphic and hydraulic models to these measurements to reconstruct channel geometries, flow conditions, and sediment transport conditions.

Current/future questions: How big were rivers on ancient supercontinents? What do ancient river deposits tell us about past terrestrial hydroclimate? To what extent can we apply paleohydraulic reconstructions to deposits on Mars?

Understanding how ancient depositional systems responded to climate change is crucial to predict how modern systems may respond to ongoing climate change. We can make field observations to decipher how ancient systems responded to hyperthermal events such as the Paleocene-Eocene Thermal Maximum (PETM), a global warming event that occurred ~56 million years ago. 

Current/future questions: What determined the sensitivity of ancient rivers to climate change, and what does this mean for modern rivers?

Flume experiments allow us to investigate landscape evolution under experimentally accelerated timescales. Processes observed over hours to days in the laboratory can represent geomorphic dynamics that unfold over millennial to multi-millennial timescales in natural systems. These observations help us to bridge the gap between modern surface processes and the stratigraphic record.

Current/future questions: Do observed differences between non-vegetated and vegetated experimental landscapes help us interpet the pre-vegetation rock record? What factors control shoreline evolution in experimental landscapes?

River planforms reflect the quasi-equilibrium form of channels in response to water supply, sediment supply, slope, and other factors. Knowledge of ancient river planform therefore provides insights into ancient river dynamics. However, planform can be challenging to interpret from the rock record. We can using modern river data to find simple predictors of specific geometries/processes, such as planform (see left), that can be applied to ancient systems.

Current/future questions: How does river planform change in response to environmental disturbances (e.g., vegetation decline)? How has planform changed throughout Earth history?