11/7/12
Geologic Activity
Throughout billions of years, Earth’s ground has been formed and transformed through a combination of geological events resulting in canyons, basins, mountains, etc. One of the oldest and most unique geological park is the The Grand Canyon. Today, the Grand Canyon is consider one of most fascinating natural wonders of the world due to its natural features and rock deposition that date back to millions of years ago.
The Grand Canyon is a canyon divided by the Colorado River flowing at its bottom and its walls are decorated by different color layers of rock. It is due to this rock deposition and layering that the canyon has become a spot for geologist to study and of great tourism. As you can see in the image below, the canyon has eighteen (18) different rocks layers and three (3) sets of rocks. At the very bottom it’s the Vishnu basement rocks that date back to approximately 1,200 million years in age, which denotes the earliest rock sediment for the canyon in that area. At the very top is the Kailab limestone dating 270 million years ago. This limestone was actually formed under the ocean as geologists have discovered. But due to tectonic plate action, the plateau was uplifted and the canyon gradually changed over the years. Today the kailab limestone rises up to 9,000 feet in height.
As the image shows, the layers 18-16 (starting from the bottom) are categorized as the vishu basement rocks, which are the oldest. Following are the Supergroup Rocks which include the layers from 15-12 aging up to 740 million years. All these layers are considered the Precambian era. The last group is the Paleozoic Rocks that include the remaining layers 11-1.
Together these layers tell the geological history of the canyon and how it came to form as well as provides the age of the canyon and although it is unsure as to how the Colorado River carved its way downward into the canyon and began dividing the plateau, the canyon is today
Cited: National Park. http://www.nps.gov/grca/naturescience/naturalfeaturesandecosystems.htm