Andean-scale highlands in the Late Cretaceous Cordillera of the North American western margin

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• 作者：Jacob O. Sewall^a ; ^{sewall@kutztown.edu} ; Henry C. Fricke^b
• 关键词：North American Cordillera ; paleoelevation ; Campanian ; Sevier ; Cretaceous ; climate modeling
• 刊名：Earth and Planetary Science Letters
• 出版年：2013
• 出版时间：15 January, 2013
• 年：2013
• 卷：362
• 期：Complete
• 页码：88-98
• 全文大小：2126 K

文摘

From the Late Jurassic through the Cretaceous, collision between the North American and Farallon plates drove extensive thin-skinned thrusting and crustal shortening that resulted in substantial relief in the North American Cordillera. The elevation history of this region is tightly linked to the tectonic, climatic and landscape evolution of western North America but is not well constrained. Here we use an atmospheric general circulation model with integrated oxygen isotope tracers (isoCAM3) to predict how isotope ratios of precipitation would change along the North American Cordillera as the mean elevation of orogenic highlands increased from 1200 m to 3975 m. With increases in mean elevation, highland temperatures fall, monsoonal circulation along the eastern front of the Cordillera is enhanced, and wet season (generally spring and summer) precipitation increases. Simulated oxygen isotopic ratios in that precipitation are compared to those obtained from geologic materials (e.g. fossil bivalves, authigenic minerals). Quantification of match between model and data-derived ¦Ä¹⁸O values suggests that during the Late Cretaceous, the best approximation of regional paleoelevation in western North America is a large orogen on the scale of the modern Andes Mountains with a mean elevation approaching 4000 m and a north-south extent of at least 15¡ã of latitude.