Latest Issue

2016 Vol.125 No.2

Eastern Grand Canyon from Desert View （Arizona, USA）

The Paleozoic strata deposited in the shallow sea and dunes along the western margin of Pangea occur as almost horizontal beds, ornamenting the 2,000m high Colorado plateau surface. Rapid uplift induced a pre-existing meandering river system to incise rocks quickly, carving a V-profiled canyon. The uplift has likely been driven by an uprising movement in the upper mantle; nonetheless, the well-known steep cliffs will soon change into boring gentle slopes immediately after this uplift stops. In contrast to the magnificent view of various strata at a glance, the strata themselves are not unique, as they can be traced extensively in the surrounding areas.
　Turing off Interstate Highway 40 （the old Route 66） to the north, visitors can easily reach the southern rim of the canyon by car, traveling to the Mather Point and/or Bright Angel Trailhead, and enjoy the familiar authentic views. By driving east for one hour or less, visitors can reach Desert View to observe the eastern part of the Grand Canyon and can see the meandering stream of the Colorado River itself in a widened valley. The evening view from this vista point will give a slightly different impression of the Grand Canyon. Some visitors may recognize the Great Unconformity between the horizontal Cambrian beds and the underlying Precambrian units.

（Photograph and explanation: Yukio ISOZAKI）