Vishnu schist and Zoroaster granite

Photo taken from the bottom of the Grand Canyon, Arizona in January 2002. This is some of the oldest exposed rock in the world, with an average age of 1,700 to 2,000 million years. These rock layers were once the base of an ancient mountain range, comparable to the Rockies, which over time completely eroded away and now provides a tantalizing glimpse of the enormous time scale on which geologic events occur. The Colorado River is in the foreground.
© Mark Meyer Photography

Monument Creek Camp has a large group site on the western hillside of the drainage near the pit toilet and there are about half a dozen small group sites scattered above the creek in a small valley. Monument Creek is a perennial water source, but there is typically very little of it. More often than not, it can be found below the monument and just upstream from it.

Hikers can easily spend half a day exploring the area and a day hike down to Granite Rapids is strongly recommended. The squirrels and mice in this area are very aggressive. Protect yourself and the animals by following Grand Canyon’s Food Storage Guidelines.

Vishnu Schist and Zoroaster Granite

This layer averages about 1,700 to 2,000 million years old and consists of mica schist. These were originally sediments of sandstone, limestone and shale that were metamorphosed and combined with metamorphosed lava flows to form the schist. This layer along with the Zoroaster Granite were once the roots of an ancient mountain range that could have been as high as today’s Rocky Mountains. The mountains were eroded away over a long period of time and new sediments were they deposited over them by advancing and retreating seas. The colour of this layer is dark grey or black.