“100 Classic Hikes in Arizona – Second Edition” by Scott S. Warren
Published by The Mountaineers Books
Distance: 4.5 miles round trip
Difficulty: Easy
Hiking Time: 3 hours
Elevation: 5,800 to 5,500 feet
Situated in the starkly beautiful northern region of Petrified Forest National Park, Onyx Bridge is one of many petrified logs strewn across this desolate reach of Arizona, It earned its name because it spans a small wash. Certainly as interesting are the countless other pieces of fossilized wood found along the hike. Most of this hike falls within an established wilderness area, and the hike mostly crosses open terrain rather than following an actual trail…
Like the countless other mineralized logs in the park, Onyx Bridge was washed to this former flood plain during the Triassic Period – about 225 million years ago. After being covered by mud, volcanic ash, and silt, the original wood fiber was slowly petrified by silicon enriched groundwater. It is interesting to keep in mind that those trees, now jettisoned in a parched and desolate desert, are a product of an era when early dinosaurs roamed lush forests. Just as fascinating, though, is the fact that the entire region was subsequently inundated by a vast freshwater lake, and that enough time has since passed to allow erosion to expose this geologic story.
March 4, 2004
I decided on this hike at the last minute and didn’t make a photocopy of the directions like I usually do. I wasn’t worried because the volunteer gave me a topographical map at the trailhead. She apologized because she couldn’t give me very good directions but the map looked pretty straight forward so I wasn’t worried even though she said most people don’t find it on their first visit. DAMN!!! I should of brought the book. There is a reason why most people don’t find it on their first visit. The hike turned into my search pattern across the desert floor looking for the huge wash (1/10th of a mile wide by the map scale) nicely drawn on the map. As an extra bonus, it was a simplified topo map so most of the hills simply did not appear on it which helped a great deal (sarcasm). The petrified wood strewn about was pretty cool however and the entire region reminded me of a mini-Canyonlands National Park, Utah.
Here are the pics (Click on the picture to see full size):
These are low res pictures. I can send you higher quality pictures if you want them
