New Perspectives on Landscape Evolution on the Hawaiian Islands

The Hawaiian islands are an excellent natural laboratory for studying the controls on long-term landscape evolution because (1) both landscape age and initial condition are known, (2) rock properties are generally uniform (but locally heterogeneous), (3) most of the global variation in annual rainfall is represented, and (4) there is no tectonics beyond the known subsidence history. Our work reinforces the perspective that much of landscape evolution - primarily canyon cutting - is a threshold-limited process. We show that commonly neglected thresholds largely define the relationship between climate and landscape evolution. Our work is unusual in that most studies of the role of thresholds in modulating climate control of erosion have been conducted in tectonically active settings where a balance between rock uplift and erosion rate creates opportunities researchers can exploit. Interestingly, however, it is the lack of tectonic activity in the Hawaiian islands that ultimately makes them better suited to definitively establish and quantify the role of thresholds in landscape evolution.

Speaker: Kelin Whipple, Arizona State University