Over 200 million years ago, during the Late Triassic Epoch, the land that now forms Arizona was on the supercontinent Pangea near the equator, in a tropical climate. Huge conifers towered over a low-lying land cut by rivers and streams. As the trees died and fell, many were carried downstream by the rivers, rolling and breaking off branches as they traveled. Most of the trees decayed, but some were covered by sediment before the decomposition process set in. The land was coated in ash from nearby volcanos. Water dissolved silica from the ash and it percolated down to the buried trees. The silica solution filled the tree cells, eventually crystallizing into agate. Iron, manganese and other minerals present during this process paint the agate a rainbow of colors: iron minerals create red, mustard, orange and black; manganese minerals give blue, purple brown and black colors; even green is sometimes visible, which I suspect copper is responsible for. This process turned the trees into stone, or petrified wood. In hollows of the trees created by cracking or decay, the growth of crystals was unhindered, and large crystals of clear pure quartz, purple amethyst, yellow citrine, and smoky quartz formed. [Source]
Petrified wood is common, but a small area of northeastern Arizona is special because it has the highest concentration of these fossilized stone trees, and it has been set aside as the Petrified Forest National Park. This land has a long history as a travel corridor for civilizations ranging from ancient to modern. In addition to fossil forests of petrified woods and a striking badlands landscape (more on that below), the small park also houses remnants of ancient Pueblo People, including ruins of a Puebloan Village and petroglyphs. Railroads were laid through the region in the 1880’s to connect to the Pacific Coast, and the railroad still cuts through the park today; a bridge over the tracks connects the north and south parts of the park. In the early 20th century, Route 66, connecting Chicago to Los Angeles, was constructed to also travel through this storied land. Today I-40 cuts through the park near the historic road.
Petrified Forest National Park is relatively small, as national parks go, and one can see all the sights and walk all the designated trails in a day, if one is so inclined. With an abundance of free camping just outside the park, and me not feeling well for our first couple days there, we took our time and spent four days there. I actually could have spent even more – on that final day we learned that there is a badlands wilderness area with no designated trails, but unlimited hiking and backpacking opportunity.
If you are thinking that the Badlands are in South Dakota, as I was, let me clarify. The word ‘badlands’ has been generalized to refer to the type of landscape found in the famous Badlands. Indigenous people of Montana and the Dakotas called the land ‘mako siva’ and Spanish trappers referred to it as “el malpais”, both literally translating to “badland[s]”. Badlands are comprised of soft shale and sandstone that are subject to severe erosion. These severely eroded layers are also spectacularly colorful, as the layers of sediment built up under different environmental conditions (mineral composition, pH) that create variously colored layers over time. Erosion exposes the differently colored layers as striped hills. It is really striking!
We were not planning on doing any hiking in the park until we were at the Painted Desert Inn museum and the ranger staffing the information booth recommended a hike to us. I am really glad he did! We got the opportunity to hike out into the badlands and to experience firsthand where they get the name. Each of us fell once from sliding on the soft slope of the eroded land. Our hike was just over a mile to a log called the Onyx Bridge because it spans a wash. The petrified wood in this part of the park is primarily black, lacking the rainbow colors of the more developed areas of the park, but the hike was a really fun experience and I would love to do more exploring there.
For those of you inclined to visit, I should explain more about the free camping. Many shops compete for tourist souvenir business just outside the park boundaries, and since these shops have abundant land, one way they try to lure in business is by offering free camping. This is basically just a place to park, no hookups or amenities (except treacherously decaying picnic tables), but we were literally just outside the park gates, parked for free with no worry about a late-night knock on the door. So each day we did a little touring, and a lot of relaxing.
The park may be small, but it does not lack in educational information. A museum of geology and fossils is located at the southern end of the park, and a cultural museum in a former inn at the northern end of the park. At the Rainbow Forest Museum we played in box of rubber pieces where bone casts were buried, meant to introduce kids to paleontology. Brushes were provided to uncover bones like paleontologists do. I just wanted to yank the bone out, not painstakingly brush away the debris. I probably do not have the patience to be as careful as a paleontologist!
The park is filled with fossils from the Triassic period in addition to the petrified wood. Out of curiosity, I asked at the information desk if there were any fossils we could see on a trail, and after one person grabbed another from the back, who called in yet another who wasn’t even in the building, the answer was essentially no. There is a fossil clam bed, but the part of the park it is in is not currently open to the public (a large portion of the park is currently off limits because it was only recently acquired and is not yet fully incorporated). She did say there is a plant fossil on the backside of the tepees (a badlands formation with a viewpoint parking area). The following day we walked to the backside of the tepees, passing signs admonishing visitors to not climb on the formations. Does “not climb” include not walk around off trail, even at the base? All over the park signs warn visitors to stay on the trails, so it really seemed we were walking where we shouldn’t be, and we didn’t even know what to look for. After looking at the back of the tepees, we determined that seeing a fossil would be like finding a needle in a haystack, made even more difficult by looking over our shoulders for rangers coming to kick us out. Sadly, we gave up and left.
A pueblo is building that houses a village, essentially like an apartment building with very small individual rooms and a large communal area. Maybe more like dorms, come to think of it. (At least this is what I understand from the little information provided on plaques in the park). Puerco Pueblo was a 100-125 room pueblo on the Puerco River, the remains of which are open as a visitor site in the Petrified Forest National Park.
It is interesting to learn about how the park system has changed over the years. A large petrified tree, named “Old Faithful” was hit by lightening in the 60’s, and park staff “repaired” it by cementing it back together. That would not happen in today’s National Park Service, which protects natural resources by letting nature take its course. Another example of artificially preventing erosion is that Agate Bridge, a log spanning a wash similar to the Onyx Bridge. An even more surprising development that is counter to modern park service policies is the Agate House, a partial reconstruction of a pueblo built of petrified wood. Archeologists excavated the remains of the pueblo and determined the floor plan of it. In the 1930’s the building was reconstructed.
This was a really beautiful and informative stop! Another national park I recommend you visit.