Located in the Red Cliffs Recreation Area, within the Red Cliffs National Conservation Area, this dinosaur track site features 17 well-preserved tracks. Although it is impossible to know exactly which dinosaurs made these footprints, tracks are tied to a general group of dinosaurs based on shape, size, and arrangement of toe pads. These tracks have been identified as Grallator, Kayentapus, and Eubrontes tracks, which paleontologists suggest were made by bipedal meat-eating theropods during the Jurassic Period.
Millions of years ago, dinosaurs left their tracks in sediment. Typically, the soil was wet -- part of a shoreline, a mudflat or even the bottom of a shallow sea. As the area dried, the tracks hardened. Eventually, another layer of sediment filled the prints, protecting them from erosion or damage. Very heavy dinosaurs could also leave underprints, stepping so forcefully that they compressed deeper layers of soil, essentially leaving their tracks protected underground.
Over millions of years, these layers of sediment hardened into sedimentary rock -- the same type of rock that preserves dinosaurs'fossilized bones. Then, over another long time span, erosion, weathering and geological forces gradually revealed the buried tracks. In some cases, these same forces have drastically changed the position of the land, moving it from flat to vertical.
For a track made tens of millions of years ago to survive until the present, several specific steps had to happen. The sediment the dinosaurs walked through needed to be just the right texture -- not too soft and not too hard. Prints in very wet soil would collapse on themselves, and walking in hard soil didn't make much of an impression. It also helped when the sediment that filled the tracks fell slowly and was a different type than the one on the ground. For example, falling ash drifting from a distant volcano would be a better preservative than a sudden mudslide burying an expanse of muddy tracks. And, of course, geological events must have combined in just such a way to make the tracks visible today.
Dinosaur tracks have been found on every continent of the world except Antarctica, but they're still comparatively rare. Their rarity and longevity aren't the most amazing things about them, though. Often, paleontologists can puzzle out what dinosaurs were doing when they made their tracks. Sometimes, the tracks reveal more information about dinosaur behavior than skeletal fossils can.
Trackways, or collections of two or more consecutive tracks, are rich sources of information for paleontologists. For example, most of the trackways discovered so far don't include the snakelike impressions that would come from a dragging tail. This means the dinosaurs making the tracks walked with their tails held up off the ground. The lack of drag marks also means dinosaurs held their bodies up over their legs, like horses, rather with their legs splayed out like alligators.
Researchers can also calculate the speed the dinosaur moved by comparing the length of the tracks to the distance between them. In general, if the length of the stride is more than four times the length of the foot itself, the dinosaur was running, not walking. Researchers have also used computer models to analyze tracks and estimate the height of the dinosaur's hip.
But there's more to be learned from trackways than how a single dinosaur species walked or ran. A collection of tracks can reveal information about social behavior. The greatest dinosaur track discovery took place February 2000 on the outskirts of the small city of St. George, Utah. Dr. Sheldon Johnson, a retired optometrist, was in the process of leveling a sandy hill on his property when he discovered a number of large rectangular sandstone blocks. While moving one of the rocks he found bumps on the underside. Under closer inspection Dr. Johnson discovered that they were perfect dinosaur track casts. He turned over another rock and another, and his excitement grew as he discovered track after track. Dr. Johnson wondered who would be interested in this find and who would be willing to come out and inspect the tracks he had uncovered. Dr. Johnson contacted paleontologist experts and was told this was the largest set of dinosaur tracks ever found. Within a short time the dinosaur tracks became the most popular attraction in St. George.
The tracks were made from about 200 to 205 million years ago during the early Jurassic period. At this time southern Utah and Arizona were much nearer to the equator and were close to sea level. There were numerous streams and lakes throughout the area. It was a perfect habitat for the carnivorous Eubrontes dinosaurs such as the Dilophosaurus. The Dilophosaurus was the largest dinosaur of the early Jurassic period measuring 19 feet long and 6 1/2 feet tall. It had crests on each side of its head. It stood on two legs with three-toe clawed feet measuring 13 to 18 inches long. From the back of the foot protruded a dew claw or hallux. A fully grown Dilophosaurus weighed around 900 pounds.
Smaller 4 to 8 inch tracks were made by the ichnogenus Grallator such as the slender meat eating Megapnosaurus. Additional small one-inch Batrachopus dinosaur tracks of an early crocodilian have been found. Other unique features include swimming tracks, tail drags and rippled surfaces. A number of fossils have been identified in the area including those of fish, water lilies, stromatolites, ostracods, conchostracans, and conifer branches with needles still attached.
The Johnson farms dinosaur tracks lie within the Moenave formation which includes layers of sandstone, mudstone, and shale. The tracks were found at the bottom of a three-foot thick layer of sandstone overlaying mudstone. The fossil evidence indicates that the Johnson farm was located along the margins of a shallow saline lake 200 million years ago. As the water receded, dinosaurs walking through the leftover clay left impressions of their feet including scales of their skin and prints of their toes. As the mud hardened, cracks around the tracks formed. Eventually the lake level rose and buried the tracks with sand and silt. Over time the sand hardened and became sandstone thus preserving the dinosaur tracks. Within the three-foot sandstone blocks are several track-forming layers.
However, collections of parallel tracks moving in the same direction, such as the ones shown above, suggest that some dinosaurs may have traveled in groups. A single set of tracks that covers lots of area without much overlap suggests that the dinosaur may have systematically looked for food.
There's one important piece of information that often can't come from trackways -- what kind of dinosaur the tracks belonged to. Very big dinosaurs had lots of muscle and padding on their feet, so their preserved footprints don't look much like the bones scientists have for identification. And since bones fossilize best when buried quickly -- and prints fossilize best when buried gradually -- it's rare for researchers to find preserved tracks next to the skeleton of the dinosaur that made them.
- http://www.blm.gov/ut/st/en/fo/st__george/more/heritage_resources/public_use_sites/red_cliffs_dinosaur.html
- http://www.scienceviews.com/dinosaurs/dinotracks.html
- http://science.howstuffworks.com/environmental/earth/geology/stone-dinosaur-track.htm
- http://www.nps.gov/dena/naturescience/making-dino-prints.htm
How to Claim Your Find:
First you MUST answer all of the following questions via email within 48 hours of your posted log. Any missing answers will disqualify your find. Please do not post your answers in your log. This will also disqualify your find. In either case your log will be deleted.
Go to the coordinates listed at the top of the page, with a tape measure and answer the following questions:
Send an email to me with the first line reading GC5JF99 Red Cliffs Dinosaur Tracks. Include how many in your party and their caching names.
Locate the main trackway that runs east to west and answer the following.
1. Observing the dinosaur tracks at the site and using the diagram "Making a Dinosaur Print" above on the cache page what type are they?
2. Using a tape measure measure one of the tracks starting at the tip of the center toe and back to the edge of the heel. Send me the length in your email (please do not post any pictures that will give away the measurement).
3. Now using your own stride walk alongside the tracks (please do not walk on the tracks). Can you match the stride of the dinosaur who made these tracks? With this knowledge estimate how tall you believe the dinosaur was that created the tracks. Do you think the dinosaur was walking or running? What brings you to this conclusion? Add this information to your email.
Post A PIC WITH YOUR LOG
As of June 10th, 2019 GC HQ updated the requirements for logging an EarthCache to allow the CO to request the visitor to "…provide a photo of themselves or a personal item to prove they visited the site. A personal item must be an option for those who do not want to photograph themselves. This task is acceptable only as an addition to well-developed logging tasks, not as a substitution."
So as of 06/10/19 "all" logs MUST have a pic attached with either the cacher (or group of cachers) prominently in it OR a personal item (GPS/printed icon/etc.) I will not accept cell phones as a personal item because 1) you more than likely would be using it for the pic 2) Cell phone, in my opinion, is too generic for a "personal item."If you post a group pic you MUST list the cachers names in you log.
Faliure to follow this or any part of the logging tasks will result in disqualification and your log will be "deleted!"
This cache is located within the boundaries of the Red Cliffs Desert Reserve with the written permission of reserve managers. The Reserve is a 62,000-acre scenic desert area dedicated to the protection of the desert tortoise and other rare or sensitive species of wildlife. Non-motorized recreation is allowed within the lower elevations of the Reserve on designated trails only. If a trail is not marked with official reserve signs, it is not a designated trail. Cache seekers should visit www.redcliffsdesertreserve.com before entering the reserve to be sure that their activity is consistent with rules for responsible recreation that protect this fragile habitat area.
Special thanks to Red Cliffs Desert Reserve and the BLM for granting permission to place this cache.
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Please help protect paleontological sites. It is illegal to dig, remove, or collect vertebrate fossils without a permit. Never make molds or castings, or apply anything to fossils and trackways. Never drive over, walk on or sit on fossils.
- BLM