At the Bolivia Cal Orcko Parque Cretácico, or Cretaceous Park, workers found the largest concentration of dinosaur footprints in the world on a giant 3,900 ft. long by 260 ft. high wall. These 68 million year old impressions derive from the Late Cretaceous Period when the place that we now call Cal Orcko, 5 km west of Sucre, Bolivia, was the shore of a huge lake. A menagerie of prehistoric animals came here to drink, eat, run, romp and fight, and while doing so, they left their tracks behind. These impressions solidified in the clay shorelines during dry periods, only to be covered up by more sediment that would gather more prints. Hence, layer upon layer of dinosaur footprints are now visible in the crumbling cliffside at this incredible paleontological site in South America.

Discovery of Dinosaur Footprints

Sucre is a city in the southern mountains of Bolivia. Just west of Sucre, FANCESA cement company has been mining limestone at Cal Orcko for many years, and in 1985 workers unearthed the first dinosaur footprints there. In 1994, mining excavations revealed the giant limestone wall covered in tracks. Investigations into the site began in 1998. However, once the tracks were exposed to the elements and mining operations, they began to erode and crumble. Subsequently, the area was shut down for 8 years. Then in 2006 the Sucre dinosaur park, Parque Cretácico, opened for tourists to view the striking impressions.

About 5055 footprints are strewn across the dinosaur wall, with 462 different tracks that were made by 15 different types of dinosaurs . “Most impressive of these is the world-record setting 347-meter trail left by a baby Tyrannosaurus Rex known as ‘Johnny Walker'”. (Sucre Life, “Sucre’s Dinosaur Park and Footprints” 2017).

Layers of Dinosaur Tracks

Most of the tracks take on a regular pattern. However, other dinosaur footprints lie in a confusing design, resulting in paleontologists calling it the “dinosaur dance floor”. They also discovered that there are at least 7 layers of footprints within this Bolivian dinosaur wall. As one layer falls or erodes away, another one emerges to reveal new tracks.

“The most spectacular trackways are those of quadrupedal titanosaurs, herbivore animals with a size between 15 and 25 m (Lockley et al. 2002). Footprints of bipedal carnivorous dinosaurs are very common. One trackway of a theropod dinosaur can be followed for more than 550 m and presents the longest ever recorded in the world. Trackways of ornithopod dinosaurs are less common but nevertheless demonstrate the presence of small to intermediate size animals that reached a height of about 4m. The scientifically most important tracks are those of ankylosaurs; quadrupedal ornithopods with a heavy dermal armour (McRea et al. 2001)”.

What Caused the Cal Orcko Wall?

How did the shoreline of a large lake become a steeply inclined 70 degree wall? The Sucre Life website indicates that the Sucre area was at one time a large ocean inlet. In other words, the ocean went at least as far as Cal Orcko, perhaps even further. However, there is fossil evidence that at some point it became a freshwater lake (Hippler 1998, Meyer et al. 2001).

Related: Prehistoric Human and Animal Tracks at Roccamonfina, Italy

During the Triassic and Jurassic periods, rifts formed in South America due to the break up of Pangaea. As a result, the uplifting process of the Andean mountain range started. Then during “the Cretaceous Period the Andes began to take their present form, by the uplifting, faulting and folding of sedimentary and metamorphic rocks” (Wikipedia, “Andes”). The same tectonic forces that caused the Andes Mountain range also caused the uplift of the Cal Orcko paleontological site, resulting in a wall containing many layers of dinosaurs tracks. What was once the ocean may have eventually become a beach that became an isolated lake that took on fresh water. Fossil records at the Cretacious Park reveal cat fish, crocodiles, turtles, and fresh water snails (Meyer, Ch A., et al). Eventually, the area was pushed up to a nearly vertical wall. Now Sucre sits at an elevation of 9,200 feet.

Parque Cretácico Museum and Tours

Today, the Cal Orcko Parque Cretácico is open to the public for just over $4.00. This provides entry to the museum with a variety of dinosaur exhibits that showcase skeletons and sculptures. Additionally, there are educational audio and visual resources and a guided tour to see the dinosaur wall. Although visitors are not allowed to go directly up to the wall as they once could, a new path will take them up to a few meters away. This prevents injuries from falling rocks. Visitors may also observe the wall and take photos from the viewing platform.

Fortunately, Sucre’s Cal Orcko is in the process of becoming a UNESCO World Heritage Site. This will provide $8 million in funding to help preserve the dinosaur tracks. Meanwhile, history is quickly crumbling away at the whims of erosion, as the dinosaur footprints that were left by the mysterious creatures of our distant past are forever erased.

References:

Meyer, Ch A., et al. “A Marriage between Geotechnique and Palaeontology Three dimensional vizualization of a geological monument for scientific exploration and geotechnical conservation (Cal Orcko, Sucre Bolivia).”

Wikipedia, “Andes”

Sucre Life, “Sucre Dinosaur Park”

Twisted Sifter

The Guardian