Research Activities

a pair of large field jackets at dig site
Field jackets made of burlap and plaster


Fossils in the Field

Fossils can be found at Petrified Forest year-round, but most of the paleontological fieldwork occurs during the summer months when the weather is a little more predictable. Finding fossils is like a search and rescue mission;once a bone is exposed the elements, the clock starts for all of the processes that will eventually destroy the bone unless paleontologists can get to it first. During the season, interns, seasonal rangers, and park paleontologists walk all corners of the park to find fossils coming out of the badlands. Much of what is picked up is called "float" because it is lying on the surface of the ground. But more recently, the crew has been undertaking spot excavations in order to find fossils before they weather out of the ground. When a fossil is found, paleontologists use a variety of tiny picks, knives, and glues to dig around the bone, making sure to leave as much rock on the fossil as possible. Then, the crew makes a "jacket" around the bone with burlap strips and plaster. Each time a fossil is found, paleontologists make careful notes about its geographic position, which rock layer it came out of, what materials were used to dig it up, and lots of other contextual information like noting the weather, who was in the field crew, and what time the discovery was made. Many of the fossils found at Petrified Forest can be carefully carried back in the arms of a paleontologist, but sometimes help is needed to retrieve the field jacket from one of the volunteer crews that work at the park. In the last three years, crews have helped paleontologists carry out several jackets that weighed more than 200 pounds!

jacketed fossil exposed under microscope
Fossils are removed from a jacket in the lab


Fossils in the Lab

Once the fossils are out of the ground, they are taken to the fossil preparation lab. The goal of the preparators who work there is to remove all of the rock surrounding the fossil in the field jacket, and to stabilize the fossil so that it can last in the collections in perpetuity. All of the preparation that occurs at Petrified Forest is done using a microscope and tiny tools in order to minimize damage to the fossil. Preparators also make molds and casts of fossils that can be used in museum exhibits or sent to researchers around the world. The preparation lab at the park also houses equipment for bone histology, which focuses on the microstructure of fossil bone. In this process, a small piece of bone is embedded in plastic and cut into very thin slices. Those slices are then mounted on a glass slide and ground to a thickness less than that of a human hair! When the bone is that thin, scientists can view it under a special microscope to see how the bone grew during the lifetime of that animal. Once each fossil is stable, it is assigned a unique number and accessioned into the museum collections. The curator of the museum is responsible for properly housing each specimen in the storage cabinets and facilitating loans and visiting researchers. Scientists from all over the world visit Petrified Forest in order to study the fossils from the park.
fossil and brush at dig site
Finding fossils is only the beginning


Fossils in the Literature

Paleontologists at Petrified Forest are active researchers and produce peer-reviewed scientific literature every year. When a new discovery is made, scientists make measurements, take photographs, and perform mathematical analyses to answer a particular question. What did this animal looks like? What kind of animal was this? How fast did this animal grow? How did the plants and animals interact with one another? How are the fossils from this park related to those from other places? Park paleontologists are active in the academic community. They are often asked to review scientific manuscripts, participate in international paleontological conferences, and talk to local and national news outlets in order to provide scientific information about the park to the public. The paleontologists at Petrified Forest are working hard to bring the science and fossil resources to everyone through books, papers, museum exhibits, and public talks. See the Published Research page for a list of publications from over a decade.

Field Seasons


The 2015 season began in May as park paleontologists assisted research collaborators from Virginia Tech in excavating Triassic fossils near the park. When the interns arrived in late May, the crew monitored some known fossil sites in the Devil's Playground, including a phytosaur skull that was originally found in 1939 by University of California Berkeley professor Sam Welles. A class from Columbia College Chicago came to the park and helped excavate a metoposaur interclavicle from the Dying Grounds. The class prospected the area and brought back many teeth and interesting bones. In early June, the park crew re-opened a quarry that was found in 2014. During the 2014 and 2015 field seasons, more than 800 bones of a new small archosauromorph reptile have been excavated from that quarry and are being prepared in the fossil preparation lab. The crew leader began a mapping effort in 2015 by driving stakes into the bottom of the quarry and measuring each fossil from the two nearest stakes. In June, the park paleontologists also visited a crew from Yale, another collaborating institution that has been digging in the north end of the park for the last ten summers. The first Field Institute classes began this summer, and a visitor on a day dig with park paleontologists found a fossil from a long-snouted Triassic fish that was thought to have been extinct at the time! The monsoon season began in the middle of the summer, which requires park paleontologists to become temporary meteorologists in order to avoid getting stuck in the backcountry during a powerful thunderstorm. In July, the park crew prospected an exposure of badlands near Rainbow Forest Museum that had not been visited in the last few years. They didn't find many fossils there, but one of the interns found an arrowhead! The following week, the crew drove east onto land acquired during the recent boundary expansion. While prospecting the Newspaper Rock sandstone, the crew found impressions of plant fossils, trace fossils of animals wading through mud, and small invertebrate footprints. In August, the park paleontologists focused on a new quarry of Revueltosaurus. The new quarry is adjacent to the original Revueltosaurus Quarry, which produced the first fossils that showed Revueltosaurus was an armored pseudosuchian archosaur, not a plant-eating dinosaur. Two large field jackets were collected from that quarry. The Youth Conservation Corps helped quarry those jackets out from the field, each one weighing more than 150 pounds and containing hundreds of bones. The field season ended in late August, but the fossils collected during this time are being prepared in the lab and included in the museum collection.


Last updated: March 16, 2018

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Petrified Forest National Park
P.O. Box 2217

Petrified Forest, AZ 86028-2217


928 524-6228

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