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Pliocene uplift of the grand canyon region - time of drainage adjustment

December 31, 1972

Tertiary gravel deposits in ancient stream channels along the southern margin of the Colorado Plateaus of northern Arizona show by composition and structure that these deposits came from sources to the south and southwest at a time when central Arizona stood higher than the present Grand Canyon region. Three cobbles of basalt included in the gravel deposits have K-Ar ages of about 10.0 m.y., 12.2, and 12.4 m.y. showing that the major uplift of the plateau in northern Arizona had not taken place at that time. The present south-flowing drainage of the Verde River and neighboring streams resulted from final elevation of the northern Arizona region relative to central Arizona, and must have developed well before about 5 m.y. - the age of some basalts that flowed into the Verde Valley. Thus, the major relative uplift of the southern part of the Colorado Plateaus must have occurred within the 5 to 10 m.y. interval, or in early to middle Pliocene time. This time of uplift also was the time of major canyon erosion, including the cutting of Grand Canyon, within the Plateaus province. © 1972, The Geological Society of America, Inc.

Publication Year 1972
Title Pliocene uplift of the grand canyon region - time of drainage adjustment
DOI 10.1130/0016-7606(1972)83[1923:PUOTGC]2.0.CO;2
Authors E. D. McKee, E. H. McKee
Publication Type Article
Publication Subtype Journal Article
Series Title Geological Society of America Bulletin
Index ID 70207141
Record Source USGS Publications Warehouse