How was the Grand Canyon Formed

The Grand Canyon is a deep valley located in the Colorado Plateau, in the Arizona State, USA. Though, it is not the deepest canyon, the Grand Canyon is well-known all over the world for its massive size and colorful landscape. The dimension of the Grand Canyon is such that the length is 446 km, width range is 6.4 to 29 km and the depth is about 1.83 km.

As per geological evidences, the Colorado River was said to have originated somewhere around 60-70 million years ago and its basin about 40 million years ago. The exact date as to when the Grand Canyon was formed is still controversial. Prior scientific studies claimed the origin to be about 6 million years ago. However, according to recent geological studies, published in 2008, the Grand Canyon originated as early as 17 million years ago.

How was the Grand Canyon Formed

The Grand Canyon was formed mainly as a result of the erosive activity of the Colorado River. Certain other forces like the continental drift and the Earth's orbit contributed to the creation of the Grand Canyon. Let's discuss in brief about the formation of the Grand Canyon.

Prior to the formation of the Grand Canyon, the area was believed to be occupied by a chain of mountain ranges. These mountains after a span of million of years, had become plain due to water and wind erosion. Meanwhile, due to the sudden climatic changes, the oceans moved over these areas and deposited rock layers. This process was repeated many a times, resulting in the deposition of several rock layers. At times, the time span between two deposits was so vast that the upper layer was eroded completely.

At this point in time, the ancestral Colorado River came into existence (about 70 million years ago). In those times, the course of the river was subjected to change due to alteration in the surrounding terrain. The tributaries of the Colorado River also contributed to the erosion process. About 16-17 million years ago, the Colorado Plateau was uplifted due to pressure under the Earth's crust and movement of the tectonic plates.

The rise in the elevation from the sea level prevented the submersion of these areas by the seas. At this time, the Colorado River continued to erode the canyon sides. Apart from the erosive activity of the Colorado River, the debris flow (fast flowing mass of rocks and boulders resulted from flash flood) played a major role in the widening and deepening of the Grand Canyon.

All these factors contributed to the formation of the Grand Canyon. It is an intriguing feature, especially to geologists as it exposes rocks that are billion of years old. The rock layers of the Grand Canyon, as we have seen, are due to the depositions by the oceans and seas. Speaking about the layers of rocks, the Grand Canyon reveals the geological history of more than two billion years; the Vishnu Schist found at the bottom of the canyon. Between the rock layers of 1.5 billion years old and 500 million years old, there is a gap of about 1 billion years, which is believed to be a period of erosion.