For centuries, the carbon-rich rock from Karelia has been credited with healing and even magical properties. Scientists do not find confirmation of this, and the popularity of the stone is explained by its truly mysterious origin. RIA Novosti tells what is known about the nature of shungite and the real prospects for its use in the national economy.
The lands of the Olonets province, located between the Ladoga and Onega lakes, amazed from ancient times with their blackness. The color of the soil was given by rocks coming out to the earth's surface. Local residents made black paint from them. At the beginning of the 18th century, by order of Peter the Great, the extraction of black shale was organized in Karelia. Now they can be seen in the decoration of the fountains of the Summer Garden, in the Kazan and Isaac Cathedrals, the Winter Palace and many other buildings in St. Petersburg.
Academician Ozeretskovsky described in detail the black lands around Lake Onega and came to the conclusion that there is probably a coal deposit here. During the war with Turkey, geologists studied in detail the deposits near the village of Shunga. It was then that the name "shungite" appeared. The government wanted to use the stone as fuel, but tests showed it was completely unsuitable for this, and interest in the deposit gradually faded.
Failed oil
Nevertheless, scientists continued to study shungite. Why is the carbon content so fluctuating in it - from 99% to the very minimum? Where does quartz come from? How and when did this stone form? A variety of hypotheses have been put forward. For example, Academician Vernadsky suggested that this is some special form of amorphous carbon, which did not have time to crystallize. It turned out that shungite rocks are so different that they should be called "shungite-1", "shungite-2", "shungite-3". There is also a brilliant variety, which is a highly fossilized bitumen - anthraxolite.
Having studied the chemical and isotopic composition of shungites, scientists have come to the conclusion that they were formed from organic remains about two billion years ago. It is assumed that at that time there was a supercontinent Rodinia on Earth, the atmosphere was already saturated with oxygen and life, still primitive - blue-green algae, bacteria - was actively exploring the oceans. In the shallow sea, which is now modern Karelia, layer by layer accumulated sand, clay mixed with organic matter.
“These are sapropel-like sediments. They are also known from modern lakes, as well as from some seas. These substances are used by man even in a form not transformed by nature. And nature has worked very hard on shungites. Their organic and mineral matter has gone through several stages of transformation, traces of which we are identifying, says Mikhail Filippov, Doctor of Geological and Mineralogical Sciences, Chief Researcher of the Laboratory of Geology and Technology of Shungites of the Department of Mineral Resources of the Institute of Geology of the Karelian Scientific Center of the Russian Academy of Sciences, author of several monographs about shungites.
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Millions of years have passed, and the ancient sea of Karelia was buried under later rocks. The hydrocarbons that make up organics were transformed into gas and oil, penetrated through the pores in the reservoirs and accumulated in underground traps.
“Oil fields were accumulating. Those ancient sandstone reservoirs containing oil now contain anthraxolites - a solid, almost pure carbon,”the scientist continues.
The movement of tectonic plates, the collapse of the supercontinent interrupted this natural petrochemistry. A piece of the continent, crushed by monstrous tension, plunged into the earth's crust, where it was pierced by numerous hot melts. They heated up deposits of sediments up to four hundred degrees and would have turned them into graphite, but there was not enough pressure.
“The depths were shallow. Only in the zones of contacts with melts a graphitoid was formed,”says Filippov.
In fact, shungite rocks are an oil field that has not survived to this day, having turned into stone.
Mikhail Filippov calls the chain of these events "the Shunga phenomenon" and proves that it was the same on other ancient continents.
“The Franceville Basin in the Republic of Gabon is a complete analogy, and there are anthraxolites. In America, there are signs of this phenomenon,”says the geologist.
According to him, in the Proterozoic era, there was immeasurably more oil on Earth than it is now, but these deposits have not survived.
Unique but common
The reserves of the Zazhoginsky shungite deposit are estimated at 35 million tons. Back in the 1930s, Soviet scientists intended to use stone in many different ways, but in the end they are mined mainly for ferrous metallurgy and the production of coloring pigments. Shungite is currently not in demand as a finishing material.
The ability of shungite to absorb toxins, absorb moisture, and serve as a feed additive for livestock is still being studied. Shungite molecular transformation is considered promising for use as additives in paper machine bearings.
Recently published works where shungite is considered as a cheap source of graphene. This is reported, for example, by American researchers in the journal Carbon. They believe that the carbon-rich varieties of shungite will be useful in the production of lithium-ion battery anodes.
As for cosmetics and water filters containing shungite, it should be borne in mind: these rocks are extremely rich in associated elements. Besides heavy metals, there are also radionuclides. There is no reliable scientific information about the healing properties attributed to the stone.
Tatiana Pichugina