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Melissa BignessUpward Bound Geology Student |
| The Creation of Zion| The Virgin River| Colors| | |
250 million years ago Zion was a relatively flat basin near sea level. Sands, gravels, and muds were carried from surrounding mountains and deposited into the basin in layers. The weight of these layers caused the basin to sink, meaning that the top surface remained near sea level. Over some time of the land rising and falling, and temperature changing, eventually 10,000 feet of material accumulated. The layers that were once just deposits turned into stone. Another factor that effected Zion's creation was the slow vertical uplift of a huge block of the crust caused the elevation to rise from near sea level to as high as 10,000 feet above sea level. Beginning about 6 to 20 million years ago the entire Colorado Plateau region began to rise. This was probably due to plate tectonics. The uplift that occurred gave streams greater cutting force. The streams began eroding and cutting into rock layers that were forming deep, narrow canyons.
The Virgin River looks like a creek, but has the muscle of the mighty Colorado River. The North Fork of the Virgin River cut Zion canyon, which is a deep chasm with nearly vertical walls. The north fork of the Virgin River has carried away several thousand feet of rock since the uplift began. Zion Canyon is still being formed today by the Virgin River, which drops from 9,000 to 1,000 feet within 200 miles!
Zion is a very colorful park. The minerals within the rock, streaking and staining of the surface, and desert varnish are responsible for the colors in the rocks. When streaking and staining occur, only the surface gets colored. Iron-rich water flows over a surface, resulting in usually a red or black color. Salts also cause streaking and staining. Salt evaporation can leave a white stain on rocks. Desert varnish looks like a shiny brown to black coating. Desert varnishing is a result of iron and magnesium oxides on some rock faces.
In the early evening we hiked to Canyon Overlook and watched a breathtaking sunset. What a great way to end the day! Above is a picture of what we saw.
This page was created by Melissa Bigness.
If you have any questions or comments please feel free to contact me at mishka_67@yahoo.com
This page was last updated on May 20, 2002 .