Drainage and Landscape Evolution in the Bighorn Basin Accompanying Advection of the Yellowstone Hot Spot Swell Through North America

Eduardo Francisco Guerrero
College of Earth, Ocean, and Atmospheric Sciences, Oregon State University Corvallis, Oregon, USA
[email protected]

Mantle plumes have been recognized to express themselves on the surface as long wavelength and low amplitude topographic swells. These swells are measured as positive geoid anomalies and include shorter wavelength topographic features such as volcanic edifices and preexisting topography. Advection of the topographic swell is expected as the lithosphere passes over the plume uplift source. Waxing topography occurs at the leading edge of the swell and is expressed as an increase in rock uplift that is preserved by rivers and landscapes. Advection of topography predicts a shift in a basin from deposition to incision, an increase in convexity of a transverse river’s long profile and a lateral river migration in the direction of advection.

The Yellowstone region has a strong positive geoid anomaly and the volcanic signal, which have been interpreted as the longer and shorter wavelength topographic expressions of the hot spot. The Yellowstone swell has accompanied the eruptive hot spot track to the northeast at a rate of 3 cm yr-1 and began acting on the Bighorn Basin’s landscape after 3 Ma, yet the age control on the erosional evolution of the region is relative. Our project revisits the classic study area in the Bighorn Basin of Wyoming and Montana, which is in leading edge of the swell. My project seeks to de-convolve the mechanisms that acted upon the Bighorn Basin and forced the change from depositional to erosional regime.

AAPG Search and Discovery Article #90157©2012 AAPG Foundation 2012 Grants-in-Aid Projects