Red Gulch Dinosaur Tracksite

Erik5 Dr. Erik P. Kvale, a research geologist with Indiana Geological Survey and Director of the Iowa State University Geology Field Station in Shell, Wyoming, discovered the Red Gulch Dinosaur Tracksite in May 1997 while exploring the Bighorn Basin with Cliff & Row Manuel, Fran Paton, and fellow geologist Dr. Al Archer. The tracksite contains literally thousands of rare Middle Jurassic age dinosaur tracks embedded in oolitic limestone. Located on public land near Shell, Wyoming, this site covers 40 acres set-aside by the USDI-Bureau of Land Management.

DISCOVERY

Discovery Site2 While standing at part of the tracksite, Cliff asked Erik if they should be looking for tracks. Erik replied, “No, this is the wrong formation — but there is one right at our feet,” pointing at a track located beside them. Erik knew that dinosaur remains in the Middle Jurassic Sundance Formation are a rarity in North America, and there are only a few known tracks. Instead, in the Sundance, one commonly finds fossil shells left from an ancient sea. Yet, these dinosaur tracks were clearly made just at the shoreline, not in deep ocean water.

HISTORY

The tracks were laid down approximately 167 million years ago. The discovery was significant in that the tracks should not be there, according to prevailing geological wisdom. This area, and most of Wyoming, was believed to be under water during that timeframe — covered by the ancient Sundance Sea.

Recognizing the significance of the find, the group notified the Worland office of the Bureau of Land Management (BLM), who organized a multi-disciplinary team of scientists and researchers to research and document the site. Dr. Kvale was one of the scientists selected to conduct the geological research, along with Dr. Michael Brett-Surman, Museum Specialist, Smithsonian Institution, National Museum of Natural History, and Dr. Gary Johnson, Professor of Geology, Dartmouth College.

DSC00926ss The tracks are preserved in limestone in an area that was once a beach that fringed the Sundance Sea, a vast inland body of water. The individual footprints are aligned in dozens of trackways that can be traced for lengths of up to 12 meters across the bedrock surface. The tracks have been dated at 167 million years old and most range in length from 2 inches (4cm) to 10 inches (25 cm). The largest of these dinosaurs would probably have stood less than 7 feet (2.3 m) in height. Scientists do not know which dinosaur species made the tracks, since dinosaur fossils from this timeframe are so rare. Research continues in an effort to understand more about these fascinating trace fossils.

The bedrock surfaces upon which the dinosaurs walked are also covered with wind-generated ripple marks. Comparison of the orientation of the fossil ripple marks and the directions of the trackways suggest that the dinosaurs were walking into the wind. Meat-eating dinosaurs probably made these trackways; thus, their upwind travel suggests that they might have been hunting. Many of the trackways are sub-parallel indicating that the group was walking as a pack.

Last Modified 2-10-2009

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