New Early Cretaceous Dinosaur Tracks from Southwestern Arkansas

Earlier this summer some new tracks, most notably sauropods and theropods, were found in southwestern Arkansas, in the same gypsum quarry where other tracks were located in the 1980's. Back then, Jeff Pittman had been doing some work at the quarry and often was displeased with the potholes he had to drive across every day. In late 1983 he and Dave Gillette confirmed that the "potholes" were actually thousands of sauropod tracks. The tracks were destroyed the next year. An account of that story can be found here.

Large theropod track in the Cedar Mountain Formation near Moab, Utah

The large theropod tracks at the Arkansas site look very similar to a new track series near Moab near the base of Ruby Ranch Member of Cedar Mountain Formation (picture right). This site is currently being developed into a protected interpreted trail by the BLM. Stay tuned for more information on this site as it becomes available. The site is being worked on by Brent Breithaupt (BLM regional paleontologist), Neffra Matthews (BLM), and Martin Lockley (CU Denver - retired). It should prove to be a very interesting site once it is described. Work is planned to compare this site to the Arkansas site. 

Working at the Cedar Mountain track site last summer, September 9, 2009
(l-r: Me, Scott Foss [BLM], Neffra Matthews & Brent Breithaupt)

The story below is the report from the University of Arkansas, my alma mater, who worked most recently on the Arkansas tracks. I was not involved in the work at this site. If you have any specific questions please direct them to Steve Boss. 

Large Field of Dinosaur Tracks Uncovered in Southwest Arkansas
High-tech and traditional techniques used to study footprints 
Wednesday, October 05, 2011 [link]

This July 12, 2011, photo provided by the University
of Arkansas shows tracks from a three-toed
dinosaur that researchers are studying
 in Southwest Arkansas. (AP Photo/
University of Arkansas, Russell Cothren)

FAYETTEVILLE, Ark. – The discovery of a large field of dinosaur tracks in Arkansas has researchers busy using cutting-edge technology and traditional techniques to learn all that they can about the animals and environment that existed there 120 million years ago.

The track site, found in southwest Arkansas, covers an area of about two football fields and contains the fossilized tracks of several species and tracks from multiple animals of the same species, some of which have never been previously documented in Arkansas. The site will help researchers learn not only about the creatures that once roamed through the area, but also about the climate during the Early Cretaceous period 115 to 120 million years ago.

“The quality of the tracks and the length of the trackways make this an important site,” said Stephen K. Boss, who led the National Science Foundation-funded project. Based on the rock in which the footprints were found, researchers have a good idea of what the climate would have been like.

“Picture an environment much like that of the shores of the Persian Gulf today. The air temperature was hot. The water was shallow and very salty,” Boss said. “It was a harsh environment. We’re not sure what the animals were doing here, but clearly they were here in some abundance.”

The most dramatic tracks found, those of a three-toed dinosaur, measure about two feet long by a foot wide. The researchers believe the footprints might belong to Acrocanthosaurus atokensis, one of the largest predators ever to walk the earth. The site also contains the giant prints of sauropods, large, long-necked plant-eating dinosaurs such as Pleurocoelus and Paluxysaurus. Other prints pepper the site as well, but it will take scientists some time to determine what other creatures might have walked through that area.

“Through tracks, we can learn all sorts things about dinosaur biomechanics and behavior,” said Brian Platt of the University of Kansas. “Dinosaur bones can be dragged away by animals or swept out to sea. But we know that about 120 million years ago, dinosaurs walked right through here.”

Thanks to a fast-track grant from the National Science Foundation, the University of Arkansas office of research and economic development and the J. William Fulbright College of Arts and Sciences, a team of researchers spent two weeks studying the site, which is on private property. In addition to chisels, hand-held brooms and plaster, some scientists brought along their computers. Jackson Cothren and Malcolm Williamson, researchers from the department of geosciences and the Center for Advanced Spatial Technologies at the university, documented the tracks using LiDAR, short for “light detection and ranging.” They used two different instruments to map the site.

First, they used a Z+F Imager 5006i mounted on a cherry picker. The imager is a phase-based scanner that emits a constant beam of laser light, which is swept across the landscape to measure and record up to 500,000 points per second.

The second unit, used to record an overview of the site from the ridge above, is a Leica ScanStation C10. This time-of-flight scanner incorporates discrete pulses of laser light at a rate of 50,000 per second, each recording a point in space. Depending on the path of a given laser pulse, up to four return pulses are recorded by the instrument's receiver. The location where each LiDAR return pulse originated is computed, allowing the researchers to study a three-dimensional “point cloud” representing the tracks.

By using LiDAR, the researchers will be able to view a highly accurate map of the site’s tracks and take detailed measurements of the height, width and depth of individual tracks as well as measurements of the trackways. These measurements will help them learn details about the animals’ identities, movements and behavior.

While computer imagery can give an overview of the dinosaurs, rock samples from the site can offer clues to climate.

“Because we see footprints here, we know that this surface was at one time exposed to the elements,” said Celina Suarez, a postdoctoral researcher at Boise State University who will be joining the faculty at the University of Arkansas in the fall of 2012. This exposure means that scientists can learn information about the frequency of rain and amount of evaporation that affected this site 120 million years ago. Using this site and others, they can reconstruct a regional paleoclimate during the Early Cretaceous period, which may help them make predictions about Earth’s future climate.

“This site will add to the knowledge of both the animals and climate of the Early Cretaceous,” Boss said. “Scientists will be studying these data for many years.”

Other researchers involved with the project include geosciences master’s candidate Terryl Daniels; senior geosciences major and Honors College student Alex Hamlin; junior geosciences major Ryan Shell; Joann Kvamme, coordinator for the environmental dynamics program; and Kenneth Kvamme, professor of anthropology, all at the University of Arkansas; and Greg Ludvigson of the Kansas Geological Survey.


© ReBecca K. Hunt-Foster, University of Arkansas story from here

Save The UBC Dinosaur Track Quarry, West Paterson, NJ

Some Early Jurassic (Passaic Formation) dinosaur and reptile tracks are in danger of being destroyed in New Jersey so that condos can be built on the location. This is a petition to help gain attention to their importance and and have them included in the existing Rifle Camp Park. Please feel free to read the petition text below. A link to the petition can be found at the bottom of this post. Please feel free to sign it and pass it on. ~ ReBecca

"The UBC Quarry in West Paterson, NJ has been a unique fossil locality for scientific research and spectacular fossils from the Passaic formation in the Early Jurassic period of NJ since the 1960's. Many discoveries over the years have yielded a great deal of knowledge to the scientific community in the area of trace fossils (ichnology) during this unique time period.

Large museums and universities have done research projects and collected at the quarry to add to their collections and preserve these fossils. Ironically most of the fossils from this quarry are in private hands and not in a museum for folks to enjoy. The quarry was once an active quarry for many years but now has been sold to a developer to create high end condos that overlook NYC.

The remaining fossils in the quarry will be forever lost if the developers are allowed to demolish the remaining section of the quarry to complete their development. No more fossils from this period will ever be able to be collected again as this is the only place in NJ that has fossils from this time period. Once this section is gone there will be no more science or fossils to be gained. There is one section of the quarry left next to Rifle Camp Park that is of scientific significance that is threatened to be lost forever due to the development of these condos.

Some of the best preserved dinosaur and reptile footprints have been found in this quarry which do not compare to any other locality from New Jersey. Dinosaur tracks and fossil trace fossils have been a very unique, rare, and are an important piece of our fossil history and deserves to be protected. The state of New Jersey has done very little to protect fossil localities compared to other states in the USA and that is why we need your help. Trace fossils are a very important part of the state of New Jersey's history just like Hadrosaurus foulki and deserve to be protected, preserved and enjoyed by future generations. Let's not make this just a memory like other fossil sites in Northern NJ.

Let's make it a preserved site forever. Time is running out and only a few months left till it is gone forever. Thanks."

Online petition - Save The UBC Dinosaur Track Quarry, West Paterson, NJ

Thanks to Rissa for the heads up on this!

Fieldwork Friday #10

A few weeks ago we were working down in the Moab area, most unsuccessfully due to daily rainstorms, which made digging a bit difficult. So we had to bail on the quarry work for the most part and stuck to prospecting and checking out a few track sites in the area.

We prospected a section of Chinle Formation, where we found some wood (picture below) and isolated, indeterminate bone. Nothing to spectacular, unfortunately. And we, inevitably, got chased off by rain. A while down the road the rain blew out and we stopped to prospect a Paleozoic outcrop (I can’t remember the age, Penn. maybe). We found quite a few brachiopods, some crinoids and bryozoans - your typical invertebrate fun (I forgot to take pictures!).

We checked out quite a few track sites while we were over in the area, including the Poison Spider Mesa and Copper Ridge track sites (both in the Jurassic age Entrada Sandstone) that are managed by the BLM.

The tracks at Poison Spider Mesa are interesting because not only are they awesome tracks but also mudcracks, ripple marks and a ton of petroglyphs! These petroglyphs are from the Fremont culture. Some are really great and weird, and many of them have been vandalized by others who feel the need to leave their mark right next to these marks or some even modifying and marking over the petroglyphs. So sad and illegal!

Pictures from the Poison Spider Mesa Track Site:



Pictures from the Copper Ridge Track Site:




So, even though this is more of a paleosite visit trip than fieldwork, I thought I would include it in the series. Hope you enjoy it and have a chance to visit these sites some day!

© ReBecca K. Hunt-Foster. Please see the "Field Work Friday Rules" about the work I do and collection practices.

Museum Monday #1: St. George Dinosaur Discovery Site at Johnson Farm

I know I have fallen behind a bit with my "Fieldwork Friday" series. Sorry about that. It is not for a lack of field work, but more from an abundance of it and a lack of time to write about it. So, just to give me something else interesting to do, I thought I would write about some of the museums I have visited, and start a "Museum Monday" series. Let me know if you like it (or hate it).

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I thought I would start with the St. George Dinosaur Discovery Site at Johnson Farm (St. George, Utah). This museum is a unique, world-class dinosaur track museum. The museum sits on land that was once privately owned by Dr. Sheldon Johnson, and the first tracks were located on February 26th, 2000 to prepare the land for commercial resale. The tracks are found in the lower part of the Whitmore Point Member of the Moenave Formation (Early Jurassic in age; 195-198 million year old). After the discovery of the tracks and the large amount of visitation and press the site recieved, the land was donated to the City of St. George.

I first visited the site in 2002 when there was nothing more than a pavillion over some of the tracks and a garden shed as the prep lab. Since that time they have built a truly wonderful museum, which was finished in April 2005! I had never visited a museum where they preserve the original bedding plane for everyone to see. It is really a sight to see! They have several track blocks around for guest to view on the southeast side of the museum, with the main track layer exposed along the north side of the building. A lab where fossils (such as the numerous fish they have also discovered) are cleaned and studied, is situated in the southwest corner for visitors to view and ask questions. They also have a cool gift shop full of some unique gifts, not the same crap you see in every other gift shop.

Upon preparing the in place outcrop prior to building the museum they discovered the first ever track of a dinosaur crouching with clear hand impressions [see the paper here] was discovered. This is another really cool aspect about the museum - their website has a publications section where they add links to all of the recent research being done. I wish more museums took the time to do this. The museum also leads local paleontology tours.

You can see my pictures from the museum here.

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The museum is run by paleontologist Andrew Milner. I took a moment to interview Andrew and ask him a little about his background and how he came to work at this great museum:

(RKHF) What is your background? How did you get into

paleontology?

(AM): Did my undergrad degree at Brock University in St. Catharines, Ontario with a major in Geology and minor in Biology. Worked two years with the Canadian Museum of Nature in Ottawa

and five seasons for the Royal Ontario Museum in Toronto at the Burgess Shale in British Columbia. I've been preparing fossils since the age of 12. My interest in paleo always got in the way of school. Things have always got in my way for graduate school, but experience goes a long way and I have a lot of it. I'll complete graduate school one of these days, even if I'm in my 90's!

(RKHF) How did you get into paleontology?

(AM): I was 6 years old and had just moved from England to Quebec. My aunt came to Canada for a visit, and she picked up a Middle Ordovician brachiopod fossil off the trail and showed it to me. I was

collecting them for the rest of the hike. We lived in the Laurentian Mountains north of Montreal, so no fossils are known in this part of the Canadian Shield. Turns out that the gravel we were finding fossils in was shipped in from Montreal in the St. Lawrence Lowlands. I started digging holes in the driveway (also gravel from Montreal). My brother gave me a book on prehistoric animals and that's when I saw my first dinosaur. I've been hooked ever since, especially with lots of encouragement from my parents. My future was sealed when I started collecting Late Pleistocene Champlain Sea fossils (as seen in picture) and showing them to Dr. Richard Harington at the Canadian Museum of Nature. He was impressed with what I was finding (seal skull, complete frog, rare fishes, insects, plants, etc.).


(RKHF) What brought you to Utah from Canada?

(AM): My wife, Lynn White, graduated with a PhD in Physiological Psychology at McGill University in Montreal in 1997. She immediately sent out her CV and job applications all over Canada and the United States. She was accepted at University of Wisconsin, University of Prince Edward Island, and Southern Utah University in Cedar City, Utah. As soon as Lynn said Utah, I said let's go! The paleo of Utah being the key factor for me. We drove from Montreal to Utah in a moving truck in August, 1997.


(RKHF) What has been your favorite part about your job in St. George?

(AM): I think my favorite part of the job is when we are excavating new sites. I don't know what it is about this area, but as soon as we start digging we usually make a significant discovery. Getting to work with and meet so many interesting people is an added bonus.


(RKHF) What is the most professionaly important/significant thing you have done while at the track museum?

(AM): Difficult to choose from because so much has gone on here in such a short period of time. I suppose I would have to list as number one, helping build a museum to preserve the site.

Significant discoveries would be the world's largest and best preserved collection of theropod dinosaur swim tracks ever found, and the discovery of one of only five crouching theropod dinosaur traces. Ours is the only one in the world with clear hand impressions.

A restoration of Early Jurassic environment preserved at the St. George Dinosaur Discovery Site at Johnson Farm, with the theropod Dilophosaurus wetherilli in bird-like resting pose, demonstrating the resting trace with hand impressions. Art by Heather Kyoht Luterman, image from here.

(RKHF) Can you tell us a little more about how the track site was found, and how work there has progressed till now?

(AM): Dr. Sheldon Johnson was leveling a hilltop on his property, preparing the land for commercial resale. He had taken most of the hill away when a large sandstone block rolled out of the back of his dump truck. He noticed a three-toed natural cast of a Eubrontes track. His first thought was that the dinosaur was still in the rock and its foot was sticking out. It wasn't until he continued flipping rocks over that he realized that they were in trackways, and he was looking at sandstone infills of the tracks. Two weeks after the discovery Jim Kirkland called Wade Miller, Alden Hamblin and myself to go and look at the site. This was before the public found out about it. We met the press on that day and that's when people started visiting the site in huge numbers.

The City of St. George became involved and put up a fence around the site. Volunteers began

giving tours and the city hired a volunteers coordinator. Martin Lockley, Jim Kirkland and other came to the site to start proper documentation. That's when the in place "Top Surface" tracksite was discovered (one site now covered by the museum) and we had to stop excavating the "Main Track Layer" (original surface discovered by Sheldon). This is also when we discovered the tail drag with the Eubrontes trackway which secured $0.5 million from the federal government toward a museum. I was hired on by the City in October, 2001.

Hard to believe, but in less than 5 years after the discovery, a museum was being built over the site. Unfortunately our building is not big enough to house everything we have collected and we desperately need another building. Most of the dinosaur swimtrack collection is outside under make-shift wooden boxes and they deteriorating despite our effort to try and preserve them.

(RKHF) Do you have a favorite fossil that you have found (anywhere in the world)?

(AM): That's tough making me pick just one ... can I pick my top

five? At the St. George Dinosaur Discovery Site at Johnson Farm it would have to be discovering all of the dinosaur swimtracks in place. We have now identified well over 3000 individual claw marks and we are no where near finished preparation of the blocks. Finding a complete Anomalocaris at the Burgess Shale was a rush. The 10,800 year old leopard frog with insect part in its gut was an exciting discovery, especially since I'd always said, "I'd love to find a Champlain Sea frog!" All alone, jumping around like a crazy person on a beach along the Ottawa River when I found a Harp Seal skull was fun. Aside from the dinosaur swimtracks though, I think the best find of my life was showing Jim Kirkland where "Andrew's Site" was in the Lower Cretaceous Cedar Mountain Formation (pictured above). It's produced a new species of iguanodont (adult and juvenile), a new Fruitachampsa-looking terrestrial crocodile, the skull of a fairly large, new mammal, the tail of a small dromaeosaur, and a partial Gastonia on a lower bed. Two small theropod caudals are what made me take notice in 2002. Jim returned in 2005 to discover bones coming out all over the hill.

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Hope you have enjoyed this first Museum Monday post!

© ReBecca K. Hunt-Foster

Fieldwork Friday #2

I realize this is almost late. But it is still Friday where I am. I had hoped to post something earlier in the day for this new series, but unfortunately it didn't pan out that way. I was lucky enough to get out into the field twice this week! The first trip out was to a site that is not being worked by myself, but by a fellow paleontologist. The second trip was out today to prospect more of Rabbit Valley, like last week. I had held off on posting in hopes of finding something cool I could talk about today, but that was not to be. We did find quite a bit of fossilized wood, probably in the Dakota Formation (fall blocks), but was very scrappy.



The work we did earlier this week was visiting a track site in the Morrison Formation north of the Moab, Utah area on BLM land. It was very interesting to see and I look forward sharing a link to the research once it is published. It was nice to also get out and see some great geology. The area around Moab is always fun to see and think the geology is excellent! I always see something new on every trip. We were able to walk from the Morrison Formation to the Entrada Formation (also Jurassic in age) during our hiking that day, and had a great view of the La Sal Mountains in all their snowy wonder. I found two small, faint tracks in a sandstone covered in ripple marks from the lower Summerville Formation (picture on right). I also found an owl pellet (recent), full of tiny mouse bones, so that was a fun plus to poke that around. No fossilized bones on this trip.



On the ride home we drove though the canyon along Highway 128 (see map below). This is a great drive! If you have never driven this route I strongly encourage you to. It follows the Colorado River for quite a distance and you are surrounded by great cliffs of Moenkopi, Chinle, Wingate, Kayenta and Navajo. I know Silver Fox is familiar with this area, and she has many great post about it on her blog. I made sure to wave at Fisher Towers for her as we passed by. The sun was setting and it turned the Moenkopi and Chinle Formations turn an amazing deeper red. I hope to camp in the area some day so I can experience it again. Well worth it and a great way to send a fun day!

View Larger Map
© ReBecca K. Hunt-Foster. Please see the "Field Work Friday Rules" about the work I do and collection practicies.

Update on the "Stolen" Dinosaur Tracks

Here is an update on the "stolen" tracks...

Hi folks,

I have new information for everyone on this. First of all, thanks for everyone's comments, concerns, etc! Ive contacted the auction house, have spoken with the owner of this track slab, and will be contacting the land owner. Turns out that several loads of rock from land north of the museum (now SGDS property) were transported to another property about a mile away. SGDS staff and volunteers were collecting from these rock piles about two years ago. Since that time, the former land owner who is one of our foundation members and donors has sold the land. Tracks were found there by the new land owners while moving rocks around, and they have sold specimens. A paper trail is being provided, and I'm going to talk to people involved about donating the tracks to our museum for possible tax right-offs. I'm also hoping to obtain photographs of specimens they find so that I have a record of what they've found and no one is falsely accused of doing anything wrong. No one ever accused anyone in this case, although some may have misinterpreted/assumed I was saying otherwise.

Turns out I don't have photos of the specimen up for auction, although it does look very much like another example we have from the same stratigraphic unit. The specimen owner is going to email me photos of others that he has. I'm hoping that it might be retracted from the auction somehow. One of my growing concerns is that seeing tracks from SGDS properties for sale, even though in this case the specimen doesn't belong to the City of St. George and the owner has the legal right to sell it, will tempt people to steal more tracks and vandalize tracksites/specimens to make a "fast buck". As I mentioned before, this has happened on at least two occasions in the past year.

Anyhow, everything's good between all parties and no hard feelings. Happy to see that people involved clearly understand where I was coming from and my concerns, and they seem to respect it!

We do have a list of stolen tracks and I'm hoping to post those on the internet one of these days so we can try and "track" them down. ;)

Thanks for listening!
Andrew

Stolen Dinosaur Tracks?

I would like to pass this message on from Andrew Milner, who is the St. George [Utah] City Paleontologist and St. George Dinosaur Discovery Site at Johnson Farm Museum Curator. This is very sad and disturbing to see more fossils up for auction, especially when they are taken from private land illegally [suspected in this case]. Please feel free to pass this along!

Hi folks,

Dr. Martin Lockley from the Dinosaur Tracks Museum at the University of Colorado at Denver sent me a link to an auction site where some theropod dinosaur footprints are for sale next month. His message simply says, "St. George Theropod tracks for sale!!!!"

Here's the link:

http://historical.ha.com/common/view_item.php?SaleNo=6012&LotIdNo=8001&txtSearch=&hdnSearch=true


There is very little doubt in my mind that this particular specimen was stolen from across the street from the St. George Dinosaur Discovery Site at Johnson Farm museum (SGDS) from one of four track surfaces we call the Stewart-Walker Tracksites. To top it off, this specimen looks very familiar to us. Good thing we have detailed descriptions and photographic records of all specimens found exposed on private and City of St. George properties around the museum, so it shouldn't take us too long to figure out if the specimen in question was stolen. If it was then we can do something about it. By the way, we have had a few thefts and vandalisms in the last couple of years.

Don't know if everyone knows this, but they should. If fossils were collected from private land without the landowners permission then it is theft and trespassing. All of the properties around the SGDS museum are private properties or belong the City of St. George. The SGDS are the only ones with permission to collect from these surrounding properties. You should also know that collecting or replicating vertebrate traces fossils (vertebrate body fossils as well) is illegal on federal and state lands if you don't hold a permit.

Sorry for posting this, but it really upsets me when scientifically significant fossils like the one for auction go missing, and when most likely it is from the site we have all worked so hard to protect! Why protect it? Simply for research and public education purposes, and to preserve it for future generation to observe, enjoy, and study. The SGDS is one of a kind and cannot be duplicated! By the way, one of the track types on this block is extremely rare and we are presently describing them in detail.

Please feel free to pass this along to others and/or post it on groups, listservers, etc.

Thanks
Andrew R. C. Milner
St. George City Paleontologist and SGDS Curator