3 Basic Provinces
AZ Hot Springs!
Arizona Volcanic Fields
AZ Electromagnetic Anomalies
AZ Volcanos
Copper Porphyry
Earth Song Poem
Gems and Minerals in AZ
Meteorite Map
Periodic Table Refresher
The Painted Desert

 Geology:Basic Principles  

Roadside Geology of Arizona
Roadside Geology of Arizona

An Introduction to Grand Canyon Geology

An Introduction to Grand Canyon Geology

Arizona has a rich and fascinating geologic history.  The illustrations on the next page give a brief overview of its progress courtesy of The University of Northern Arizona’s Geology Department.  These are the best illustrations available I’ve found. You'll also find additional links at the end of this article.

Illustrations of the Paleogeography of the Southwest

Chris Scotese's Brilliant Animation of Earth 250 Million Years in the Future!

 Take a bucket of sand, add water and rock it back and forth.  Drain the water out and turn the bucket upside down.  You’ll find the heaviest materials sank to the bottom while the lightest ones moved to the top.  That’s exactly the way the Earth works.

Heavy iron and manganese materials are in the center of the Earth.  Lighter minerals “float” on top.

Now, imagine a pan of slowly boiling chicken soup with the characteristic film on top.  As the heavy lower liquid moves from the heat, the film on the top moves, wrinkles and changes shape.

You’ve just watched plate tectonics at work.  The same principles apply.

The lithosphere is a collection of those lighter minerals.  It forms the land we see and the 12 plates that form the Earth.  Deep beneath it is a slow moving, heavy, hot liquid moving the lighter tectonic plates.

 As the plates move, some areas are weaker along faults and fissures.  Steam is generated by friction carrying some of the lighter, water-soluble minerals into their openings, filling them with  mineral rich solutions.  Porphyry copper deposits are formed exactly that way.  Divide Arizona into 1/4th’s and the southeast quadrant is hydrated copper carbonate country.

 Volcanoes come in two types: basalt (shield) and conical/silicic.

Basalt is iron and manganese rich so it’s heavy, spreading out in black puddles around the opening hence the term “shield”. .

Silicic or stratovolcanoes are the ones we normally think of as volcanoes with the tall, conical shape.  Lighter silica, a quartz like material, liquefies and spews from the opening.  As it cools, the silica becomes hard and bottles up the opening.  The pressure builds again and it erupts.  Sometimes, the “cap” is large enough to hold, forcing the material to find a new path to release the pressure, forming side vents.  It’s almost always accompanied by steam.


Arizona Outback Prospecting Clubs

Arizona Geology in 3D

Arizona Information

Chris Scotese's Brilliant Animation of Earth 250 Million Years in the Future!

Northern Arizona University Paleogeography Site


Map of Arizona.jpg (55174 bytes)

Map of Arizona


The rez.jpg (39886 bytes)

Map of the reservations and Four Corners 


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