Welcome to the Petrified Forest of Arizona, and a review of the natural forces that made petrified wood.




Pangea was the combined seven continents of earth during the Paleozoic era 251 million years ago.

That era lasted 180 mya down to the Cenozoic era which started about 65 Mya. This era is separated into three geological periods:

Triassic (250 to 200 Mya)

Jurassic (200 to 145 Mya)

Cretaceous (145 to 65 Mya)

Triassic period ushered in the extinction event and started the drifting of continents apart.

94 million years ago the continents, moving at 5 inches per year, had a long ways to go.

To the left California to Alaska, pushed up by the Pacific Plate, a emerged from the sea. And east, the Appalation mountains on theAtlantic Plate, has emerged as a land mass.

Gulf of Mexico to the Arctic Sea is a shallow ocean.

But opposing plates from the east and from the west will raise the land mass out of the sea and into a solid continent.

A land bridge will arise to become Central America.

64 million years ago, land from Texas to Canada are still submerged under a shallow sea; Alaska and Canada are above sea level, and the shallow  Seaway is slowly flowing into the ocean.

East and north-east of North America, east from the Mississippi, to the Appalachian Mountains, are low marshlands which will last for a long time.

The Rocky Mountains push higher, and land in the middle pushes up as the Atlantic and Pacific plates overlap each other. The sea caught in the middle slowly drains to the south.

Lush vegitation and trees dominate the landscape as the sea continued to flow south. 

During this time period the dynosaurs died off.

Thirty million years ago Arizona in places was elevated  by tectonic action to a mile high. The sea that in ancient times covered the land had long ago drained away.

Hot spots deep in the earth spawned volcanos large and small.

The land was covered with lush vegitation, trees and mega fauna including mastadons, saber tooth cats, lions, and sloths as large as a Volkswagon.

But volcanos, and later man, ended all of that. 

Volcanic erruptions started the chain of events that made petrified wood. Water flowing from eruptions knocked down trees.

Silaceous volcanos spewed out silica and metals that stained the silica in bright colors, which then covered the trees.

Then debre hundreds of feet deep covered the trees. The chemical action of the silica replaced cellulose shielded tree cells, cell by cell, with silica.

The final result was colorful hard wood as hard as steel, but brittle, and a brightly colored landscape we now know as the Painted Desert, and further west, The Grand Canyon.

The Mogollon Rim thought to divide the land between natives who preferred to live in high places, from natives who wanted to live in the lower desert areas.

But it also defines the edge of the volcanos that spewed out the lava which covered the tops of the mesas. Mesas, hard to believe, were once ground level, and areas between mesas was eroded. 

The top of the Grand Canyon was once ground level, with several volcanic flows entering it to block the flow of the Colorado River.

The last eruption was a thousand years ago, and that one buried several Indian camps.

 Canned Histories TM by donkelly