Desert Messenger

22 www.DesertMessenger.com March 19, 2014 By Jenn Jedidiah Free for RocksInMyHead™ While on the road last year, we traveled through Winslow and Holbrook, AZ, home of the world famous "Rainbow" petrifi ed wood like that preserved in Petrifi ed Forest National Park located just east of Holbrook. While traveling through the vast expanse of desert, it is diffi cult to imagine a landscape covered with dense tropical forest. But in reality, around 250 million years ago, the desert southwest was a full of trees- mostly conifers and palm trees. The environment was similar to a modern tropical environment, and it was because of that tropical, forested environ- ment that Arizona has its state fos- sil. Petrifi ed wood was designated the state fossil of Arizona in 1988. Yes, petrifi ed wood is a fossil. It is wood that has been changed to stone through processes known as permin- eralization and replacement. Two specifi c conditions must exist in order for a fallen tree to turn into petrifi ed wood. First, the fallen tree or limb must get buried in an environment devoid of oxygen, like mud or heavy sediments. In an anaerobic environ- ment, the organic matter will not de- compose. The second condition is that there must be mineral-rich water fl owing through the sediments and the wood. Permineralization occurs as minerals fl ow into the original tissues of the wood and replace the organic matter molecule by molecule. Empty spaces in cells are fi lled with crystals. The original shape and structure of the wood is retained, though all or- ganic matter has been replaced by minerals. This process can take any- where from hundreds to thousands to millions of years, depending on envi- ronmental factors. Petrifi ed wood is found throughout the world. Here in Arizona, Petrifi ed Wood can be found locally along the Colo- rado River and Martinez Lake. Another site nearby is Alamo Lake, where gorgeous speci- mens of Petrifi ed Palm Wood can be found. The most well- known, largest, and by far the most beautiful Petrifi ed Wood found in Arizona is in the area in Eastern Arizona located near Petrifi ed Forest Nation- al Park. Referred to as "Rainbow", the famous specimens from this area near Holbrook and Winslow are clearly some of the most beautiful petrifi ed wood in the world. The geology of the Holbrook area is rich and varied. The deposits left from ancient rivers and sea beds created the Chinle formation, which consists of colorful Badlands, fl at-topped mesas, and sculptured buttes. Within the Chinle forma- tion are layers of volcanic tuff, mudstone, and sandstone. The sandstone layer consists of reddish mudstone and brown sandstone, and it is this layer that contains the large amounts of beautifully colored petrifi ed wood known throughout the world as "Rainbow". The pet- rifi ed wood found in this layer has been dated to the Jurassic Period around 213 million years old, give or take a couple million years, and has been identifi ed as ginkgo and conifer. Other fossils found in this area are of giant reptiles and am- phibians, such as Postosuchus, a huge pre-historic crocodile. The color of petrifi ed wood de- pends on what minerals are present when it is forming. Typically it is some form of quartz or chalcedony with various other minerals found in trace amounts. In the Holbrook area, a silica solution produces specimens with varieties of quartz such as agate, jasper, and some- times opal, or even pockets of clear quartz crystals or purple amethyst. The colors in petrifi ed wood are the result of the trace minerals in the solution. Copper, cobalt, or chro- mium produce a green or blue color for example. Iron oxides create reds, browns, and yellows. Man- ganese produces pink and orange, while blackish/yellow and some- times green comes from manga- nese oxides. Black is the result of an abundance of carbon, and white is created by an excess of silica. If you are heading east from Quartzsite, the Holbrook/Winslow area is a great place to stop for a few days and explore. While collect- ing petrifi ed wood is illegal within the boundaries of Petrifi ed Forest National Park, there are several lo- cations around Winslow and Hol- brook where collecting is open to the public. When you go, be sure to also visit the Park, as well as the lo- cal towns and shops. It is amazing to see entire shops full of enormous fossilized trees, and the Painted Desert is equally as breathtaking as the Rainbow Colored Trees that are its prized possession. For more information and maps to the Winslow and Homer collecting areas come to RocksInMyHead, A37 Rice Ranch, in Quartzsite. We also have a nice selection of Rainbow Pet- rifi ed Wood, as well as books, maps, tools and more. We are open 7 days a week from 10 to 5 through the end of March and into April. Phone is 605-376-8754 and you can visit us online at RocksInMyHead.com. Amazing world of Rainbow colored trees ADVENTURES WITH ROCKS First locally-owned and operated music station in Quartzsite, Arizona. Proudly serving the communities of Quartzsite, Bouse, Brenda, Rainbow Acres, La Paz Valley and beyond, since 1988. Quartzsite Radio • Quartzsite's Favorite "CLASSIC HITS" • Local Information • Weather • 24 Hours Day / 7 Days Week! KBUX 94.3 FM 928-927-5111 http://kbuxradio.com

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