PETRIFIED WOOD

Button 1 - This large piece of petrified tree in front of you came from private lands close to the Petrified Forest near Holbrook, Arizona. Weighing over 1200 pounds, it is a massive example of natural fossilization that occurred over the past 200 million years. With that timeline in mind, it’s possible that this piece of tree may have been around when Pangea was breaking apart into the continents we know today!

Button 2 - How does a log become petrified? It begins when a log is buried in mud shortly after it falls. Mineral-rich groundwater soaks into the log, and a weak acid is generated by the wood as it begins to break down. This causes minerals to form in the small spaces and crevices of the log. This process is called permineralization, and takes place over a few hundred years.


Button 3 - As the wood disintegrates over many thousands of years, minerals take the place of the original tissues of the log, sometimes molecule by molecule - this step of the process is called “replacement”. Some portions of wood are more vulnerable to decay, and tend to be replaced by minerals first. This results in the preservation in stone of distinctive patterns of the wood, such as tree rings in a stump.

Button 4 - The final composition of petrified wood depends on what minerals are in the water around the log. This piece of wood was buried in mud containing volcanic ash. The different colors you see are the result of the different trace minerals in the water solution. The red and yellow color you see indicates that this piece was primarily exposed to an iron solution and the black color comes from carbon.