Petrified Forest Summer of Science

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Date: September 18, 2014
Contact: Brad Traver, 928-524-6228 x 225

PetrifiedForest—There is always science going on at Petrified Forest National Park—September is the time for a summary of the summer's activity. Every year, seasonal employees, researchers, and summer interns swell the park's science staff and get out into the field to make new discoveries.

Not far from an area called the "Dying Grounds" that has been frequented by paleontologists since Charles Camp of the University of California made important discoveries in the early 1920's, this summer's paleontological crew located an animal new to the park's records. Unearthed from a layer dated at 220 million years old, the animal was once thought to be a type of dinosaur (from partial remains found elsewhere) but is now believed to be an ancestor of both crocodiles and dinosaurs. About 500 bones of at least 6 different individuals of different sizes were found at the site. The adult was not large—about six feet long, standing about three feet off the ground. Similar animals have recently been found at sites in Texas and Madagascar—the scientists involved in all three are collaborating on a paper for peer review and publication. In the lab, the bones are being carefully removed from the dirt and rock that has encased them for so many years. Work at the site will continue next summer.

Last summer, crews identified what they are calling the pond site and found fossil bones of several relatively larger amphibians. This year, the focus was to look at the site at its smallest scale. The crew excavated promising chunks of the pond bottom and brought them to the lab. Under a microscope, fossil bones,teeth, and fish scales the size of sand grains were found. An estimated 80 different animals may be represented by these fossils—small fish, reptiles, and amphibians—which will take many months to identify. The Triassic pond site yielded some data last year, more and different data this year, and is expected to yield data for some time to come. As with all science, these different datapoints will be built into a larger story over time that could help us better explain what this environment was like in the Late Triassic.

Lastly,a new partial survey for fossil tracks revealed evidence of Triassic Period horseshoe crabs in five different places with trackways up to four feet in length, and a few reptile footprints, about 1" in size. All the tracks are in the same sandstone layer, about 223 million years old. While some fossil tracks were known to exist in the park, the partial survey this summer expanded our knowledge significantly. More track survey work is anticipated next year.

This summer, our partners at Yale University returned to the site they have been studying for several years in the northeastern corner of the park and found another micro-invertebrate fossil locality. Our partners at Virginia Tech also returned to the area this summer but they worked a site outside the park, with our staff's assistance.

Just this month, after park interns had returned to school, the Burke Museum (associated with the University of Washington) conducted field research in an area a mile or two south of the pond site in the expansion lands and found another animal that is new to the park's records. Just in the first day's excavation, they identified at least 14 individuals of this animal in a trove of bones.

Paleontologist and paleontology program contact—Dr. William Parker 928-524-6228 x 262 Summer Interns: Adam Marsh, Ben Kligman, and Shelby Matsuoka.

This summer was the second summer of the three year project to identify and record archeology on the park's newly acquired lands. On approximately 2000 acres in both block and linear configurations, this summer's crews identified over 80 new archeological sites and returned to a couple of dozen more to update records for modern mapping. The sites include habitation sites as well as sites where stone tools were produced from local petrified wood. There are several important points from the summer's work.

First,the high density of sites encountered last summer continued in this year's work, leading archeologists to expect high site density to continue in all areas where the landscape is suitable for human use in the expansion lands.

Second, sites ranging from early Archaic (BC7000–1500) to Pueblo IV (AD1350–1500) have been found just in this summer's work, which is consistent with the full range of time periods found elsewhere in the park. Within the Pueblo II and Pueblo III periods, in the middle of this sequence, both jacal (a wall construction style of sticks and mud) and masonry building techniques were used to build above ground structures.

Finally, a story of habitation site selection may be emerging. Basketmaker pithouse villages (BC1500–AD750), which are becoming a common find in the park, appear to move from lower dune ridges close to washes in early occupation periods to higher sites, including mesa tops in later periods. Basketmaker is unique because this represents the first time when groups of people are settling into villages together.

A specific rock art project was undertaken by intern Nicole Lohman who evaluated various techniques for recording the hundreds of thousands of rock art glyphs in the park. These techniques ranged from digital recording on iPads to hand drawing all of the glyphs. As part of her work, complete recordings of two important rock art sites were made and a technique involving drawing on acetate sheets overlaying large scale photographs of each glyph panel was determined to be the most effective.

Incorporating student interns into archeological work in the park is part of approaching Petrified Forest as a teaching laboratory. In addition to the work conducted by Nicole Lohman, independent research projects were conducted by all of the interns this summer. These projects were presented at the 2014 Pecos Conference and a portion of this research will be included at an invited poster session atthe 2015 Society for American Archeology meetings this coming spring.

Next year will be the third and final year of the archeological survey and recording project on the park's expansion lands. We expect to be able to fill in some but not nearly all of the gaps in our knowledge.

Lead Archeologist and archeology program contact—Mr. William Reitze 928-524-6228 x 268. Archeologists: Iva Lee Lemkuhl, Amy Schott. Seasonal archeologists: Gregory Luna Golya, Erina Gruner, Robert Sinesky. Summer Interns: Nicole Lohman, Nicole Kulaga, Caitlin Ainsworth, Carlyn Stewart, Kathryn Turney.

Over Labor Day weekend, Petrified Forest held a small version of a bio-blitz, in which crews of citizen scientists record all the species of plants and animals they encounter within a 24 hour period. Over 50 enthusiastic volunteers donated over 800 hours that weekend to prepare, record, and report their findings. Preliminary results indicate around 400 species of plants and animals were recorded on the park's newly acquired lands, which had not been broadly studied by park scientists before. The results of the bio-blitz will be vitally important to the park as a baseline dataset of species diversity and geographic distribution on these lands. It would be beneficial to conduct another blitz after a wetter monsoon season (this year was pretty dry in the park) to see what additional species might surface.

In a partnership with the Arizona Game and Fish Department, known prairie dog colonies in the core park were mapped and an extensive survey of the expansion lands was performed to identify colonies for future mapping. Working together, we hope to be able to improve the health of the prairie dog population in the park which has been susceptible to plague in recent years.

Although there are reports of sightings, this year's Milksnake was the first captured and marked individual since 2007. Milksnakes are uncommon, nocturnal, and live underground which makes them rare to encounter. In what is probably attributable to climate change, javelina and ringtail were found for the first time at Petrified Forest this year.

With limited staff and volunteers, our summer crew continued the park's long-standing study monitoring the small animals in the park using the following techniques: 

-Visual Encounter Surveys—Established a set of randomly generated points in all habitattypes and began a systematic search for all-taxa surrounding those points.        

-Nighttime Road Surveys—Completed 23 surveys over 15 weeks. Found 367 animals including 59 snakes of 8 species and amphibians of 6 species (at least one individual of the 8 known snake and 7 known amphibian species in the park).

-Active Reptile Trapping—Trapped 25 days at 7 permanent sites yielded 376 animals, mostly lizards, but also snakes, amphibians, and small mammals. Seventy-five were recaptures from previous years meaning 80% of the captures were new animals added to the study.

-Incidental Captures—All methods not included above. Captured 105 animals, 14 were recaptures from previous years meaning 87% of the captures were new animals added to the study.

Biologist, ecology lead, organizerof the Bio-blitz, and program contact—Mr. Andy Bridges, 928-524-6228 x 267. Biological Technician: Clinton Helms. Summer Intern: Alex Lim

Park scientists continue field work on a smaller scale through the fall, winter, and spring while preparing for another busy summer in 2015. They expect to make more new and important discoveries then.

Last updated: February 24, 2015

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