A enigmática elevação do Plateau Colorado

quarta-feira, junho 23, 2010

The enigmatic rise of the Colorado Plateau

Rebecca M. Flowers

-Author Affiliations

Department of Geological Sciences, University of Colorado at Boulder, Boulder, Colorado 80309, USA

How and when the Colorado Plateau attained its current mean elevation of ∼2 km has puzzled scientists for nearly 150 yr. This problem is most dramatically manifest when standing on the rim of the Grand Canyon, viewing the extraordinary 1500-m-deep gorge carved into nearly horizontal sedimentary rocks that were deposited during the 500 m.y. prior to plateau uplift when the region resided near sea level. What caused the elevation gain of this previously stable cratonic region in Cenozoic time? Did the source of buoyancy for plateau uplift arise from the crust, lithospheric mantle, or asthenosphere, or through some combination of the three? Why did this low-relief plateau escape significant upper crustal strain during uplift, in contrast to the Cenozoic surface deformation that is so strikingly apparent in the high-relief landscape of the surrounding Rocky Mountain, Rio Grande Rift, and Basin and Range provinces (Fig. 1)?

Figure 1.
Topographic map of the Colorado Plateau and adjacent provinces.




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