During a comprehensive expedition to the Lena River delta, scientists from the Institute of Petroleum Geology and Geophysics. A.A. Trofimuk SB RAS left the Arctic Circle, on the island of Sardis to study the section of Neogene (23-2.5 Ma) and Quaternary rocks.
In the process of work, the specialists found in the breed clear prints of leaves of plane tree, beech, alder, willow and magnolia fruit, which is a real sensation.
Unique finds
According to experts, this find was a big surprise, because nowadays broad-leaved plane trees grow only in warm latitudes – in the Mediterranean, Southeast Asia and North America.
“Prior to this, only mineralized, charred wood remains and conifer cones, as well as the fruits of the American gray walnut were found in the sediments of the Sardakh island section,” says Irina Khazina, a senior researcher at the laboratory of paleontology and Cenozoic Mesozoic and Cenozoic strains. – Nobody has ever discovered prints of leaves of deciduous trees in this region – this is a truly unique find.
The locations of fossil heat-loving floras in the Arctic are known from sediments of more ancient Paleocene-Eocene age (about 65-55 million years ago), when the climate on our planet was so favorable that even in the north of modern Yakutia subtropical forests grew with palm trees and redwoods. However, in the younger sediments in the Eurasian part, so far beyond the Arctic Circle, prints of leafy floras were not found. So far, they are described only from the Neogene of Denmark, Great Britain, Iceland, Alaska, Fr. Banks (Canadian Arctic Archipelago).
Imprint of a leaf of a plane tree
The leaf flora discovered by the specialists of INGG SB RAS has an early-Middle-Iohian age (23-11.6 Ma). According to Leonid B. Khazin, a researcher at the Laboratory of Micropaleontology, Candidate of Geological and Mineralogical Sciences, the most suitable conditions for the growth of deciduous trees occurred in the optimum Miocene (about 16 million years ago) when the climate in the Arctic was warm enough for the existence of vegetation of this type.
“In order to take a fresh look at the ancient climate and its changes, it is necessary to more accurately determine the age of rocks containing unique finds and understand why vegetation of this type was spread in such high latitudes,” says Leonid Khazin. – It is believed that in those days the continents already occupied a position close to the present.
Willow leaf imprint
Another look at the ancient climate
The imprint of the plane sheet is an important proof that in the early-middle Miocene (23-11 million years) in the Arctic, deciduous forests grew, which meant it was warm and humid. Other specimens of fossil flora, such as beech, alder, and willow, also indicate this. Scientists call the magnolia fruit an even more surprising discovery – no one has yet discovered this plant in the north.
According to Olga Borisovna Kuzmina, senior researcher at the Laboratory of Paleontology and Mesozoic and Cenozoic Candidate of Geological and Mineralogical Sciences, coniferous taiga appeared in the Arctic between 10 and 4 million years ago, when the climate became much colder. Only later was it replaced by the tundra landscapes we were used to.
Fossil Magnolia Fruit
Modern look magnolia fruit
It is worth noting that the prints of any leaves are unique. As a rule, pollen and spores can be found in fossil deposits, and seeds, fruits and, especially, leaf prints are much less common. Scientists note almost perfect preservation and clarity of prints, which greatly simplifies the task of identifying plants. It is possible with the naked eye to discern the shape of the leaf, the borders of its edges and veins.
“In order for the leaf to leave its imprint on the breed, it must immediately be in special conditions after falling from a tree,” says Olga Borisovna Kuzmina. – For example, fall into a pond where there is no flow of water and no access of oxygen. Apparently, this is what happened in our case.
Further studies will establish the age of the fossil flora more accurately. In the laboratory of paleontology and Mesozoic and Cenozoic stratigraphy of INGG, Siberian Branch of the Russian Academy of Sciences, rock samples will undergo chemical treatment in accordance with modern techniques, pollen and spores will be extracted from them, and then experts-palynologists examine them under a microscope.
Imprint alder leaf
In order to determine the types of plants found with maximum accuracy, employees of the Central Siberian Botanical Garden of the SB RAS are involved in the work. According to Irina Khazina, it is planned to involve colleagues from St. Petersburg and Vladivostok who are involved in fossil flora.
Continued research
To get to the island of Sarda can only be on a boat from the research station “Samoilovsky Island”, so not all of the discovered finds could be taken to the mainland. In particular, the found imprint of the magnolia fruit remains on the island. Next year, scientists plan to return for it and conduct additional research – find out the exact age of the rocks and look for new fossil remains. According to Leonid Khazin, the chances of finding many more flora samples are high.
Scientists of INGG SB RAS are sure that in the future there will be even more interesting discoveries.
Employees of the Institute point out that because of the inaccessibility of the Arctic, humanity has so far little data on vegetation that was in this region during the Neogene period.
“The unique samples of the broad-leaf flora discovered by our scientists will change the perception of specialists about the scale of climatic variations in the geological past,” says Igor Nikolayevich Eltsov, director of INGG SB RAS. – In essence, today’s so-called global warming is only an insignificant episode in the history of the Earth. And the climate swings were swinging in the past without anthropogenic impact much stronger than today. I believe that this work is worthy of publication in leading journals such as Nature and Science.
Press Secretary of INGG SB RAS
Pavel Krasin
Photos provided by I.V. Khazina
Source: electronic periodical “Scientific Russia”
Translation: Google
