PLATOCHRON · A new understanding of the uplift and incision of the Colorado Plateau from classical and electron spin resonance thermochronology

A new understanding of the uplift and incision of the Colorado Plateau from classical and electron spin resonance thermochronology

Orogenic plateaus are key features of the Earth’s surface with average elevations of several kilometres, low relief surfaces and arid climate. They have a strong impact on atmospheric circulation and precipitation patterns, and thus on the erosive capacity of rivers. Continental plateaus show similarities in crustal thickness, heat flow, high elevation, and complex interactions between tectonics and climate at their margins. Although orogenic plateaus have been the subject of many geophysical and geological studies, the role of mantellic processes and magmatism on uplift and the contribution of surface processes on the relief evolution of plateau margins is actively debated. The Colorado Plateau is a typical continental orogenic plateau characterized by a low-relief surface at high elevation, the plateau is marginally incised by outstanding canyons including the Grand Canyon and Zion Canyon. Although canyons are key features of ecosystems and water resources across the Colorado Plateau and form some of the most dramatic features on earth, the chronology of plateau uplift, subsequent canyon incision and the controlling processes remain debated. This project will focus on landscape evolution across the Colorado Plateau in relation to forcing mechanisms including regional uplift, mantle dynamics, magmatism, local tectonics and climate change during the Cenozoic. I will provide new quantitative constraints on the canyon incision history and potential spatial variability across the Colorado Plateau using an innovative thermochronometer. Ultimately this project will provide a new understanding of processes driving orogenic plateau uplift and canyon incision. PLATOCHRON addresses 3 objectives: 1) WP1: Determine the respective influence of surface erosion and Cenozoic magmatism on the thermal evolution of the upper crust along the western margin of the Colorado Plateau 2) WP2: Demonstrate the potential of ESR thermochronometry to document rock cooling related to canyon incision and decipher the incision timing and rate of Zion Canyon. 3) WP3: Provide a new insight on the timing of canyon incision (80-60 vs. 6-5 Ma incision) and pin-point processes controlling recent canyon incision using new incision constraints from ESR thermochronology and landscape evolution modelling.

Data: CORDIS, © European Union