Sunday, June 21, 2009
Upper Granite Gorge
The Vishnu Schist begins to appear around Mile 78 and we rapidly enter the Gorge. The Colorado cuts into these ancient rocks in three sections of the river - appropriately named the Upper, Middle, and Lower Granite Gorges. The black schist is thoroughly marbled with the pink Zoroaster Granite (more aptly a geniss, given its history). The resistant rocks form a steep, narrow canyon and it's often difficult to see above the Tapeats, which marks the upper edge of the inner gorge, to the much larger and grander canyon above.