For millions of years, layers of sedimentary rocks have been accumulating information about the history of the planet. There comes a time when these layers are cut open, as if with a surgeon’s scalpel, by the turbulent rivers. Deepening their channel, they give a person the opportunity to learn the secrets of past eras. Finding such "archives of nature" is a difficult but interesting task. For almost two decades, an expedition has been studying such a place – a unique "bone lens" at the bottom of the Tobol near Kurgan. The representatives of several branches of the Russian Geographical Society are taking part in it.
Why diving to the bottom of the Tobol takes place in winter, how the work is carried out, how the project came about, what amazing finds and important scientific discoveries were made thanks to the work of the expedition – the answers to these questions were given by a member of the Council of the Sverdlovsk Regional Branch of the RGS Sergey Kondrashin and the head of the Sysert Local Branch of the RGS Vladislav Derbyshev.
– What are the work methods? How do you find, extract from bottom sediments, and lift fossils from under water at low temperatures?
Vladislav Derbyshev: The first few expeditions took place in the autumn in open water. At that time, we discovered certain difficulties in conducting search work. When the river is not ice-bound, the current is stronger and the transparency is much lower, which makes it difficult to visually search for objects at the bottom of the river. Also, the reason for the abandonment of exploration in open water was the fact that the banks at the exploration site have steep slopes. This complicates the approach to water and the delivery of equipment to dive sites, requires additional auxiliary equipment: rubber boats adapted for transporting the divers and diving, as well as devices for lifting heavy objects from the bottom. Ice diving has its advantages. In winter, the water current weakens, visibility under water increases, and the delivery of equipment to diving sites is simplified. The process of lifting heavy, large-sized objects is also simpler – a hole can be cut right above the place where the object is located, more people can participate in the lifting, which speeds up the process and makes it easier.
The search itself is carried out by a visual inspection of the river bottom by an explorer-diver. When objects of interest are found, they lift them to the surface. If a large object is partially in the ground, then the diver or a group of divers free this object, attach the ropes, and the supporting group on the ice surface lifts the object. Smaller finds are lifted along with a fragment of soil from the bottom of the river and washed.
Only highly qualified divers with experience in diving in particularly difficult conditions and skills in conducting search operations take part in under-ice work.
Sergey Kondrashin: Over the past, the participants of the expeditions have gained real experience in organizing winter diving and ensuring their safety. The rest is easy. We are happy to visit local history museums, primarily departments of paleontology. This is necessary for a successful underwater search. Man sees only what he knows.
— Were there any particularly interesting finds and stories associated with them? What is their future fate?
Sergei Kondrashin: During this time, divers have found a new species of early bison, named for the time being Bison X, as well as a new species of fossil goblin shark, which has not yet been named. There is a feeling that other previously unknown species of prehistoric animals and fish can be found in this place. There is an understanding of how and where this can be done.
The main question, which has not yet been answered: how could such a location be formed? We raise the remains of both young animals and old ones, but no traces have been found that the animals died a violent death. Some of the bones are perfectly preserved, some are badly damaged. The same questions remain for the petrified teeth of sharks, fish and rays. Some of them are perfectly preserved, some of the teeth are heavily rounded.
— How did the idea of conducting such very unusual paleontological research come about? Please tell us the story of finding a "bone lens" at the bottom of the river.
Sergei Kondrashin: In 2004, we learned from a local resident, Konstantin Burbik, that the Tobol River near the village of Voronovka washes out some bones every year. It hadn't even been a week before we went there. We dived, saw, raised – and that’s how it all began...
— What is the significance of the work of the expedition for fundamental science? What scientific discoveries have been made based on its materials?
Sergey Kondrashin: More than a thousand bones of the mammoth fauna have already been found. This is the largest mammoth fauna site in the region. The uniqueness of this location is due not only to the number of bones found, but also to a complex of other characteristics. In addition to the usual species of the mammoth fauna, the finds include such rare species as the giant rhinoceros Elasmotherium, cave lion, red deer, reindeer, and elk.
"Bison X" was determined based on the results of paleo-DNA analysis from the humerus. According to Candidate of Biological Sciences Pavel Andreevich Kosintsev, senior researcher at the Laboratory of Paleoecology of the Institute of Plant and Animal Ecology of the Ural Branch of the Russian Academy of Sciences, the results of DNA analysis from the bones of representatives of the genus of bison from Western Europe, the Caucasus, the Urals and Western Siberia showed that in its composition in the late Pleistocene there were two genetic species: Bison priscus and a new species, which for the time being received the name Bison X.
This is a previously unknown hybrid of a steppe bison and a female aurochs, which became extinct at the end of the Pleistocene. Presumably, it appeared about 120 thousand years ago. Externally, the bones of "bison X", Bison priscus and European bison are indistinguishable. These two species of bison existed simultaneously, but lived in different landscapes and had different food preferences. Until now, it was believed that the mammoth fauna was homogeneous, that the animals grazed on the same sites. Now it turned out that they had different environmental groups.
In the same place, the remains of Elasmotherium (rhinoceros) were raised from under the water, which is not uncommon for the Trans-Urals, but the specimen from Voronovka is 34,500 years old. It was one of the last Elasmotherium on Earth.
Numerous finds from the mammoth fauna site of Voronovka allow us to describe the history of the ecosystems of the region during the period of extinction of mammoths and mammoth fauna on Earth. Also in January 2015, a fragment of a ceramic vessel of the Neolithic era was found for the first time at the bottom of the river. On its thin wall there were traces of firing in a bonfire. This helped to discover a new, previously unknown Neolithic site of ancient man.
Divers also found cannonballs at the bottom of the river in the area of the "bone lens". In the 18th century, with the help of such weapons, Russian settlements were defending themselves from numerous Bashkir raids for a long time. They also found exploded 75mm caliber shells, that ended up here during the Civil War, when the front line between the White Army and the Red Army passed along the Tobol River.
Vladislav Derbyshev: During the many years of expeditions to the "bone lens" (that is the name that was given to the place for an abnormally large accumulation of remains of representatives of the Pleistocene period fauna and earlier forms of life of the Eocene period), a large amount of paleomaterial was lifted from the bottom of the river. After conducting laboratory studies and examinations, the scientists made a number of discoveries that allowed them to expand knowledge about the ancient history of the region, about the development of life on Earth as a whole.
According to the results of the expeditions, the scientists were able to identify a new species of ancient bison that lived in this region during the Pleistocene, a new species of shark that lived in the West Siberian Sea millions of years ago, change the understanding of the climate of the Turgai Strait – previously it was believed that the sea was cold because it was connected to the northern seas. However, our findings allow us to conclude that the sea had a water temperature like in subtropical seas. That is, the climate in this region was much warmer than previously thought. Also, the discovery of the skull of the woolly rhinoceros ancestor – Elasmotherium (Elasmotherium sibiricum) – expanded knowledge about this species.
— Can a completely unassociated enthusiast from another region of Russia take part in the expedition? What is needed for this?
Vladislav Derbyshev: Anyone can take part in expeditions to the "bone lens". This does not require special skills, but "extra hands" will never hurt. Every expedition, we invite volunteers to help in clearing snow, sawing holes for divers, washing the soil and much more. What is needed for this? You just need the desire to participate in the expeditions, the opportunity to come to the search site and, of course, the excitement of a discoverer! And everything that needs to be done, we will explain when you get here.
Sergey Kondrashin: Over the years, about a hundred divers have worked at the bottom of the Tobol River, several hundred people have taken part in volunteer assistance. The expeditions are carried out at the expense of their participants.
The finds of the unique expedition to the "bone lens" have already replenished the exhibitions of the Sverdlovsk and Kurgan Oblast Museums of Local History, the State Museum of History and Architecture of Neviansk, the Karpinsk and Sysert Local History Museums, the RGS Museum of Expeditions and Travels in the city of Sysert, the Pelepenko Ural Mineralogical Museum, the Alexandrov Art Museum, the Institute of Plant and Animal Ecology of the Ural Branch of the Russian Academy of Sciences. As Sergey Kondrashin noted, the mammoth fauna site on the Tobol River is a promising paleontological area and requires further inventory and study. Unfortunately, its importance is still underestimated by the scientific organizations of the country. The banks of the Tobol River and its bottom require cleaning from garbage, and the territory itself needs to be given a conservation status.