Earth Surface Processes and Landforms EarthEpigenetic Surf. Process.gorges Landformsin fluvial landscapes33, 1993–2009 (2008) 1993 Published online 12 March 2008 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/esp.1650 Epigenetic gorges in fluvial landscapes W. B. Ouimet,1*† K. X. Whipple,2 B. T. Crosby,3 J. P. Johnson1 and T. F. Schildgen1 1 Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA 2 School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA 3 Department of Geosciences, Idaho State University, Pocatello, ID, USA *Correspondence to: W. B. Abstract Ouimet, Department of Earth, Atmospheric, and Planetary Epigenetic gorges form when channels that have been laterally displaced during episodes of Sciences, Massachusetts Institute river blockage or aggradation incise down into bedrock spurs or side-walls of the former of Technology, Cambridge, valley rather than excavating unconsolidated fills and reinhabiting the buried paleovalley. MA 02139, USA. Valley-filling events that promote epigenetic gorges can be localized, such as a landslide dam E-mail:
[email protected] or an alluvial/debris flow fan deposit at a tributary junction, or widespread, such as fluvial †Now at Department of aggradation in response to climate change or fluctuating base-level. The formation of epigenetic Geosciences, Penn State gorges depends upon the competition between the resistance to transport, strength and rough- University, University Park, ness of valley-filling sediments and a river’s ability to sculpt and incise bedrock. The former PA 16802, USA. affects the location and lateral mobility of a channel incising into valley-filling deposits; the latter determines rates of bedrock incision should the path of the incising channel intersect with bedrock that is not the paleovalley bottom.