The soft mud crumbled beneath our feet as we meandered across the barren terrain. Here and there, flat blades of gypsum caught our eye, shimmering in the light. All around us lay bits and pieces of petrified wood, brilliant fusions of magenta and crimson, emerald and azure. A lizard skittered away from us and into the safety of a small dessicated shrub. Above our heads, a plump raven floated on a draft of air, lazily basking in the warm morning sun. The cloudless blue sky stretched for hundreds of miles in every direction, and a slight breeze gently ruffled our hair. As we reached the base of the steep foothills and wound our way into the ravine, the car disappeared from our sight, and we lost ourselves in the seemingly endless mounds of crumbling “popcorn” mudstone. The raven circled overhead once more and then vanished beyond the crest of a sandstone ridge, leaving us alone in the silence.
It’s not every day that one can go on a paleontological expedition; factors such as weather, funding, personnel, and other logistics quickly make planning even a short trip a rather sticky process, and the government shutdown caused by the political stalemate in Congress didn’t make things any easier. I assembled a team before the shutdown consisting of Maddi Cowen (PO ’16), Hannah Li (PO ’16), Zach Hauser (PO ’17), Wuyi “Eric” Li (PO ’17), and Jose Soler (paleontological preparator from the LA County Museum of Natural History), hammered out the logistics of lodging and food, and triple-checked the weather reports, but none of that would matter if the parks remained shuttered through the fall break weekend. We waited with bated breath as the days slowly turned into weeks without any sign of a breakthrough. Thankfully, common sense and cooler heads finally prevailed in Congress, the shutdown was ended, and a mini what-do-I-do-with-my-fall-break crisis was averted, paving the way for an unforgettable four-day trip to the Petrified Forest National Park in Arizona.
If I wrote about everything that we did, saw, and experienced, I’d probably have a five-page paper loaded with scientific literature, inside jokes, and confusing references, all of which are great for my personal field journal, but not particularly helpful for readers of this blog. So instead of boring you to death with the trivial details of everything from dawn to dusk, here are the highlights of the trip from my point of view:
1) The sunsets. You don’t see such vibrant colors in L.A., and half of the time, you can’t actually see the sun set on the horizon because it’s blocked by a building (or several). I don’t have an iPhone and thus couldn’t do a panorama shot of the entire landscape, but if you stood on a hill and slowly turned as the sun faded from our view, the light stretched from tangerine orange and sunflower yellow to shades of emerald green and ocean blue in one continuous band, a soft rainbow of color in every direction.
2) The fossils (i.e. the entire reason for going on this trip). I’ve never worked in Triassic-age rocks, let alone the Chinle Formation where we were in the park, so this was a new experience for me as well as the other students. Interestingly enough, this was also my first field experience prospecting for animals that weren’t dinosaurs. Although most people tend to associate paleontology with dinosaurs, we also work on a wide variety of other extinct animals, ranging from prehistoric fish, invertebrates, amphibians and reptiles to birds, mammals, and so on.
The Triassic period (about 250 mya to 200 mya) featured mostly large amphibians and non-dinosaur reptiles as the dominant animals in the North American ecosystem; the dinosaurs were only just establishing a foothold at this time and were far from the dominant terrestrial titans that we usually think of. As a result, dinosaur fossils are exceedingly rare in the park, so Jose and I were hoping for something more along the lines of some phytosaur elements or a metoposaur skull. We were quite fortunate to find the latter on our first day (Sunday) after I noticed a trail of fragments trickling down a sandstone hillside that led back to the larger element featured in the above photo; however, we couldn’t actually make a positive identification until Bill Parker, the head paleontologist of the park, came out with us on Monday and assessed our find. If you, the reader, can’t exactly see what makes our fossil a skull (or anything at all), that’s perfectly normal; fossil preservation is never as nice as Jurassic Park might suggest, and it often renders skeletal structures (which are already fragmented) unrecognizable to the untrained eye. Although Jose and I could tell that it was some sort of fossil, our “educated” guesses were a bit arbitrary at best.
But in essence (now having looked at some diagrams), I believe that we have the left half of the skull with an eye socket and part of the jaw hinge, and I can promise that it will look much better (and be recognizable) after being prepped back at the museum. This skull was definitely the highlight of our trip; even Bill was impressed with the preservation and semi-completeness of our specimen, and he’s been doing this work for more than a decade!
In addition to our skull, we also found a plethora of different teeth, including a phytosaur tooth that was a solid three inches long. We haven’t identified which species many of the teeth belonged to, but we definitely have a mix of reptilian and amphibian elements, as well as perhaps some fish teeth. The osteoderm featured in the photo on the right was found just a few feet from our large phytosaur tooth; osteoderms are bony structures found in the skin of both living and extinct reptiles that form scales, plates, and other hard structures, and this was actually the only one that we found on the entire trip. We also found a couple hundred scutes (another type of bony structure that overrides the osteoderms), but scutes are exceedingly common in the fossil record because they preserve well and aren’t destroyed by marauding scavengers, so we left them in the desert because none of them stood out as highly exceptional. Although it might seem like paleontologists would be happy to have any fossil, we have to be picky about what we collect, otherwise we’ll end up with hundreds of undifferentiated fragments in our collection that hold no value for scientific research or display purposes. Jose also collected what looked like a small amphibian’s limb bone, and there were plenty of GPS coordinates of sites that we marked over the two days of prospecting that might contain larger elements for future exploration. All in all, we brought back some excellent specimens for preparation in the museum that I’m excited to see in a few months!
3) The park itself. We didn’t have a whole lot of time to spend sightseeing around the park (although most visitors just drive the length of the park rather than getting out to hike around), but even while we were walking around looking for fossils, it’s hard to ignore the petrified wood, beautiful buttes and sandstone ridges, the trees changing to their autumn coats (unlike in Claremont), and the vast flat expanse that allows you to see for dozens of miles in every direction.
Petrified wood forms when the organic components and porous spaces are filled with mineral-bearing water, which causes crystals to form inside of these spaces, and can be found in practically every color. A lot of it actually looks almost exactly like real wood, except that upon closer examination, a trained eye can detect crystalline minerals (and also note that there are no large trees in the park). The photo on the left is one example of petrified wood that’s colored and textured exactly like real wood, except that it’s had its innards replaced with silicate minerals. You can even still see the tree’s growth rings and the texture of the bark on the outside of it. Sometimes scientists can even find little insects and other invertebrates that were trapped and fossilized inside of the wood. In addition, there’s plenty of other eye-candy in the park, whether it’s the rolling hills, the towering buttes, or the beautifully layered mixture of sandstones, claystones, and mudstones that were laid down more than 200 million years ago to form what can be described as a sort of rocky layered dip.
To the north, the Painted Desert, named for the red coloration of its rocks (iron and manganese minerals), punctures the dusty brown landscape and provides some awesome photo opportunities. There are ancient petroglyphs and even an old village constructed sometime around the 13th to 14th centuries, all of which add up to offer a unique mix of paleontology, archaeology, geology, and biology that’s rare among the national park system.
4) The people. You can’t have a paleontological expedition without dedicated people who are willing to spend hours in the sun walking around and hammering at rocks in order to retrieve fossils. It’s not a particularly glamorous task, very physically demanding, and not meant for some people. But when you get the right team together, it’s amazing how well you can get to know and to get along with everyone within a few days of having met each other (and after a few days of having to put up with everyone’s body odor).
The fossils are the primary motivation for going on these trips, but it’s the people who make it worth it in the end. Everyone here waited out the shutdown with me instead of jumping ship, worked really hard in the field, and had a great attitude about everything. I couldn’t ask anything more of them, and I’m proud to say that this was one of the best teams of any kind that I’ve had the privilege to work with!