Raising the Colorado Plateau

Shallow-marine rocks exposed on the 2-km-high, 45-km-thick Colorado Plateau in the western United States indicate that it was near sea level during much of the Phanerozoic. Isostatic calculations, however, illuminate the difficulty in maintaining a 45-km-thick crust at or near sea level. We propose...

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Bibliographic Details
Published in:Geology (Boulder) 2000-01, Vol.28 (1), p.91-94
Main Authors: McQuarrie, Nadine, Chase, Clement G
Format: Article
Language:English
Online Access:Get full text
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Summary:Shallow-marine rocks exposed on the 2-km-high, 45-km-thick Colorado Plateau in the western United States indicate that it was near sea level during much of the Phanerozoic. Isostatic calculations, however, illuminate the difficulty in maintaining a 45-km-thick crust at or near sea level. We propose that an isostatically balanced, 30-km-thick, proto-Colorado Plateau crust was thickened during the Late Cretaceous to early Tertiary by intracrustal flow out of an overthickened Sevier orogenic hinterland. This plateau would have been supported by a thick ( > 70 km) crustal root, which is proposed to have been the source region for hot and weak mid-crustal material that flowed eastward from the plateau toward the low-elevation proto-Colorado Plateau.
ISSN:0091-7613
DOI:10.1130/0091-7613(2000)0282.0.CO;2