How Was The Grand Canyon Formed ?
The Grand Canyon is a national park in Colorado. This natural wonder has a combination of plateaus and basins. The Colorado River cut through the rocks here. The formation of this canyon has been over a period of many thousands of years. This is evident fro the sedimentary rocks and the fossil remains. But most archeologists, geologists and scientists believe that soil erosion led to the formation of the canyon.
The Colorado River with its tributaries which flowed through different layers at different geological times is said to have caused the erosion. Other forces which might have acted simultaneously may have formed the steep-walled canyon. The change of the course of the river, volcanic activity, drift of the earth’s crust, and the orbit of the earth are believed to be other reasons.
Million of years ago the landscape of the present day canyon was believed to be filled with mountain ranges. Due to the erosive action of wind, water and ice, these peaks became plain. Sudden change in the climate in the earth caused oceans to swell and move over this area causing deposition of rocks. This process continued making many layers of rocks one on top of the other. The time gap for these formations was not consecutive. Thus many of the existing layers eroded completely before the commencement of formation of a new layer
The present day Colorado River came in to existence around this time which is approximately 70 million years ago. The course of the river was not fixed since many changes in the terrain around occurred. The plateau formed by the river got uplifted almost 16 to 17 million years back due to tectonic plate movement and pressure from the earth’s crust. The erosion of the rocks by the river continued while flash floods caused sudden wash out of many boulders and rocks thus deepening and widening the Canyon. The canyon remained without getting submerged in to the sea due to the elevation post tectonic movements.
Presence of mostly sedimentary rocks along the side walls and the fossil remains of marine life forms like mollusks, fish, corals and sea-lilies prove that the sea deposited the rocks and boulders on the plains.
Rocks put forth a history or almost 2 billion years. At the bottom layers, the rocks date back to 1.5 billion years and the consecutive layer on top dates back to 500 million years. This gap of 1 billion years between their formations is attributed to erosion.
More Articles :
Buzzle.com: How Was The Grand Canyon Formed