The Southern Rocky Mountains of Colorado, United States, have the highest regional elevation in North America, but present-day crustal thickness (∼42–47 km) is no greater than for the adjacent, topographically lower High Plains and Colorado Plateau. The chemistry of continental-arc rocks of the mid-Cenozoic Southern Rocky Mountain volcanic field, calibrated to compositions and Moho depths at young arcs, suggests that paleocrustal thickness may have been 20%–35% greater than at present and elevations accordingly higher. Thick mid-Cenozoic Rocky Mountain crust and high paleo-elevations, comparable to those inferred for the Nevadaplano farther west in the United States from analogous volcanic chemistry, could be consistent with otherwise-perplexing evidence for widespread rapid erosion during volcanism. Variable mid-Cenozoic crustal thickening and uplift could have resulted from composite batholith growth during volcanism, superimposed on prior crustal thickening during early Cenozoic (Laramide) compression. Alternatively, the arc–crustal thickness calibration may be inappropriate for high-potassium continental arcs, in which case other published interpretations using similar methods may also be unreliable.

中文翻译：

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提高西部：中新生代科罗拉多普莱诺与南落基山脉（美国）的火山岩基组合有关？

美国科罗拉多州的南落基山脉拥有北美最高的区域海拔，但现今的地壳厚度（~42-47 公里）并不大于邻近的、地形较低的高平原和科罗拉多高原。中新生代南部落基山火山区大陆弧岩石的化学成分，根据年轻弧的成分和莫霍面深度进行校准，表明古地壳厚度可能比现在大 20%~35%，海拔也相应更高。厚厚的中新生代落基山脉地壳和高古海拔，与根据类似的火山化学推断美国更西部的内华达普拉诺的情况相当，可能与火山作用期间广泛的快速侵蚀的其他令人困惑的证据一致。可变的中新生代地壳增厚和隆起可能是火山作用期间复合基岩的生长造成的，叠加在早期新生代（Laramide）压缩期间先前的地壳增厚上。或者，弧-地壳厚度校准可能不适用于高钾大陆弧，在这种情况下，使用类似方法的其他已发表解释也可能不可靠。