Dynamic topography of the western Great Plains: Geomorphic and 40Ar/39Ar evidence for mantle-driven uplift associated with the Jemez lineament of NE New Mexico and SE Colorado
A. Nereson et al., Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA. Published online 17 Apr. 2013; http://dx.doi.org/10.1130/GES00837.1. Themed issue: Investigations of North America as EarthScope Reaches Its Maturity.
The iconic, windswept landscapes of the western Great Plains are renowned for their vast expanses of low-relief topography. But in a unique sub-region of the High Plains located in northeastern New Mexico and southeastern Colorado, this flat surface has been extensively modified in recent geologic history by the processes of erosion and volcanism. The resultant landscapes are characterized by networks of deep bedrock canyons, towering mesas capped by volcanic rocks, and a stunning array of dormant volcanoes and cooled lava flows. Previous scientific studies suggested that these dramatic landscape modifications began at the end of the Miocene epoch, around five million years ago, but explanations for why these processes occurred when they did, remain controversial. This study by A. Nereson and colleagues examines a variety of data sets, including radiometric ages of lava flows and patterns of erosion, to try to distinguish between the two leading drivers of landscape change: climate versus tectonic processes. Their analysis suggests that tectonic uplift of the surface, as driven by convective flow in the Earth's mantle and magmatic inflation of the Earth's crust, is the primary cause for the deeply eroded topography in our study area. The influences of past climate changes on the erodibility of landscap
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