... for the inverse model ( Fig. 5C ). Resultant good paths show a singular cooling event at ca. 95–65 Ma. Onset of cooling from the PyCool script gives a mean estimate of 86.1 ± 7.8 Ma and a median estimate of 86.4 Ma. The Meriwhitica arch (#2, Fig. 2A ) is a subdued monoclinal structure in the westernmost...

... geologic structures in the region. Periods of compression, primarily during the Laramide, resulted in the reversal of Proterozoic extensional basement structures. Previously downdropped structures were uplifted during compressional events, resulting in the formation of large-scale monoclines, anticlines...

... Springs Canyon. Spencer Canyon appears to have had a structurally determined hydrologic advantage due to its close parallelism to the east-verging Meriwhitica monocline ( Huntoon, 1981 ). If the western Grand Canyon has only existed since early Pliocene time, any tributaries that have no structural...