Cretaceous dinosaurs have descended into the depths of the Earth

TSU scientists held a joint paleontological exploration with colleagues from Saint Petersburg State University in the valley of the river Small Kemchug (Krasnoyarsk Krai). The researchers overcame about 230 kilometers of waterways in the search for dinosaur and mammoth fauna locations. During the expedition, an unexpected fact was revealed: because of neotectonic uplifts, promising deposits that enclose the remains of ancient animals, which previously could be found in the shoreline outcrops, are becoming unavailable for direct observation.

The scientific interest of the researchers was the fact that no one before them had been in these barely passable places. On some routes, the continuous debris of trees in the river reached a length of 500 meters, so the researchers had to portage their canoes and equipment through the forest wilds.

- We found an unexpected fact - the cuts that the river usually models, exposing rocks of the Jurassic and Cretaceous periods and simplifying access to the remains of ancient dinosaurs, now were absent, - said Sergey Leshinskiy, head of TSU's Laboratory of Mesozoic and Cenozoic Continental Ecosystems.

According to the scientist, there is no doubt that during the early Cretaceous (about 100 million years ago) dinosaurs lived in the area of the modern valley of the Small Kemchug, and much later mammoths. In 2000s 25-40 km to the west, in the basin of the river Big Kemchug, TSU paleontologists discovered a new dinosaur area (today there are known more than 10 locations of remains of the ancient lizards).

Although the search for dinosaur bones in the course of the expedition was unsuccessful, researchers did not return home with empty hands. In the second terrace above the floodplain, they found a fragment of jaw of a bison that died during the last peak of global cooling.

- The fragment lies in the upper part of the long-term frost wedge, which apparently was formed about 18–20,000 years ago, - says Sergey Leshinskiy. - Due to the cryoarid climate that prevailed then in the northern hemisphere on the Earth's surface, deep cracks were formed even in the south of modern Siberia. During the spring and thaws, water had flowed into them, which, freezing, tore the ground more, leading to very large ice wedges forming.

If we radiocarbon date bison remains, the time of the death of the animal and the peak of the last ice age in the territory of southeast Western Siberia can be determined within several hundred years.

The video of the expedition (in Russian) is here