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Nearly spherical concretions that are weathering out of the Tapeats near Lonetree Canyon.
Photo by Bob Keller

Geology and Geography of the Grand Canyon!



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Fossilized sea worm holes from the Cambrian   Tapeats at the edge of the inner gorge near Lonetree Canyon.
Photo by Bob Keller
Bob Keller's Grand Hikes discusses the geology and paleontology to be encountered and enjoyed by rockhound oriented visitors and hikers at Grand Canyon.

Overview of Grand Canyon Geology and Rock Formations

Stromatolite Fossils in the Hakatai Shale

Grand Canyon Geologic Past

The Grand Canyon's greatest significance lies in the geologic record that is so beautifully preserved and exposed in its walls. What is unique about the canyon's geology is the great variety of rocks present, the clarity with which they're exposed, and the complex geologic story they tell.

There are really two separate geologic stories at Grand Canyon. The older story is the one revealed in the thick sequence of rocks exposed in the walls of the canyon. These rocks provide an amazing, but incomplete record of the Paleozoic Era of 550-250 million years ago, and scattered remnants of Precambrian rocks as old as 2 billion years. The story these rocks tell is far older than the canyon itself (which only formed five to six million years ago), a relative youngster in geologic terms.

Grand Canyon Geography

The Grand Canyon lies in the southwestern portion of the Colorado Plateau, which is a large area of the southwestern United States consisting essentially of horizontal, layered rocks and lava flows. The broad, intricately sculptured chasm of the canyon contains between its outer walls a multitude of imposing peaks, buttes, gorges, and ravines. The Colorado Plateau encompasses the Four Corner's region and includes parts of Arizona, New Mexico, Utah, and Colorado.

It ranges in width from about 0.1 to 18 miles and extends in a winding course from the mouth of the Paria River, near Lees Ferry and the northern boundary of Arizona, to Grand Wash Cliffs, near the Nevada line, a distance of about 277 miles! Its greatest depths lie more than a mile, almost 6,000 feet below the rim.

The canyon includes many tributary side canyons and surrounding plateaus. The deepest and most impressively beautiful section, 56 miles long, is within the central part of Grand Canyon National Park, which encompasses the river's length from Lake Powell, formed by Glen Canyon Dam in 1963, to Lake Mead, formed by Hoover Dam in 1936.

In its general colour, the canyon is red, but each stratum or group of strata has a distinctive hue--buff and gray, delicate green and pink, and, in its depths, brown, slate-gray, and violet.

At approximately 8,200 feet above sea level, the North Rim is some 1,200 feet higher than the South Rim.

geolava.jpg (20209 bytes) The Geology of Grand Canyon by Edwin D. McKee 1931!

Grand Canyon is unmatched throughout the world in the incomparable vistas it offers to visitors on the rim. It is not the deepest canyon in the world (both the Barranca del Cobre in northern Mexico and Hell's Canyon in Idaho are deeper, just to name two), but the Grand Canyon is known throughout the world for its overwhelming size and its intricate and colorful landscape. Geologically it is significant because of the thick sequence of ancient rocks that are beautifully preserved and exposed in the walls of the canyon. These rock layers record much of the early geological history of the North American continent. Finally, it is one of the most spectacular examples of erosion in the world.

Want to know more?
Rethinking the Formation of the Grand Canyon!

Geologists gather at the South Rim to study the Formation of the Canyon!

Here some books that I have at home. They are many out there but these are some I have enjoyed!

A Field Guide to the Grand Canyon  
by Stephen Whitney
This is probably the best and most informative guide for a hiker or visitor to the Grand Canyon to take along on their vist. I pull this out all the time to look stuff up. Most recently snakes
Beneath the Rim : A Photographic Journey through the Grand Canyon 
by C. C. Lockwood
Through breathtaking photos, award-winning natural history photographer Lockwood allows readers to embark on dizzying adventures through the Grand Canyon on the Colorado River. From a dazzling sunrise over Cedar Mesa and breathtaking views from Lava Canyon and Crazy Jug Point, these captivating photos provides an enchanting panorama
Grand Canyon, a Century of Change, the rephotography of the 1889-1890 Stanton Expedition
Robert H. Webb

Amazing Rephotography of the 1889-1890 Stanton Expedition. They recreate the phorographs, and it's amazing what has and has not changed!





The Controlled Flood in Grand Canyon 
by Robert H. Webb, Editor
Documents the research on the effect Glen Canyon Dam has had on the riverine environment of the Colorado River downstream that led to the widely publicized experimental release of water in 1996. Also presents technical reports on the impact of the flooding on the hydrological, sediment transport, aquatic biology, and terrestrial ecology of the Grand Canyon and explores the scientific and economic implications for regulated rivers elsewhere in the world. Three large maps, folded into an envelope, illustrate the effects graphically.
You can order Grand Canyon books and hiking guides from:
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All contents of all pages   copywrite 1997 - 2002  by Mike Mahanay, All Rights Reserved

Do you have any off trail stories or descriptions you would like to add?

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