Research reveals that unvegetated meandering rivers can geologically masquerade as braided rivers, suggesting they were much more common in the first 90 percent of Earth’s history than previously thought.
Research reveals that unvegetated meandering rivers can geologically masquerade as braided rivers, suggesting they were much more common in the first 90 percent of Earth’s history than previously thought.
A new Stanford study challenges the decades-old view that the rise of land plants half a billion years ago dramatically changed the shapes of rivers.
Rivers generally come in two styles: braided, where multiple channels flow around sandy bars, and meandering, where a single channel cuts S-curves across a landscape. Geologists have long thought that before vegetation, rivers predominantly ran in braided patterns, only forming meandering shapes after plant life took root and stabilized riverbanks.
The new study, published online by the journal Science on Thursday, Aug. 21, suggests the theory that braided rivers dominated the first 4 billion years of Earth’s history is based on a misinterpretation of the geological record. The research demonstrates that unvegetated meandering rivers can leave sedimentary deposits that look deceptively similar to those of braided rivers. This distinction is crucial for our understanding of Earth’s early ecology and climate, as a river’s type determines how long sediment, carbon, and nutrients are stored in floodplains.
Read More: Stanford University
Image: A view of seasonal flow in Shoshone Creek – an unvegetated meandering stream in Nevada. (Image credit: M. Hasson and M. Lapôtre via Stanford University)
