How old are some of the rock layers exposed in the Grand Canyon?

The age of the rock layers exposed in the Grand Canyon is a remarkable point of geological interest. The correct answer indicates that some of these rock layers are nearly two billion years old. This refers specifically to the Vishnu Schist, which is one of the oldest rock formations in the canyon and is part of the geological history that dates back to the Precambrian era.

In geological terms, two billion years is significant because it represents some of the Earth's earliest crustal development. The Vishnu Schist is made up primarily of metamorphic rocks, formed under extreme heat and pressure, illustrating the deep geological processes that have shaped our planet over millions of years.

While other options mention ages like less than 100 million years, approximately 500 million years, or about 1 million years, all of these are too recent to account for the ancient formations found in the Grand Canyon, which showcase the Earth’s history and the formation of tectonic features over extensive periods. Thus, recognizing nearly two billion years as the age of some rock layers gives a deeper understanding of the geological timeline and the remarkable processes that have occurred to create such a rich geological landscape.