by Lyudmila KULESHEVICH, Cand. Sc. (Geol. & Mineral.), leading research scientist, head of the Pre-Cambrian Geology Museum, Geology Institute, RAS Karelian Research Center, Petrozavodsk, Russia
The oldest rocks of 3.5 to 1.6 billion years lie on Pre-Cambrian basements. Here in Russia they are found in the Aldan shield in southeastern Siberia and within Fennoscandinavia (Baltic area) in Karelia. These formations provide an insight into the earliest evolution of the earth when its mantle was taking shape, and minerals and oxygen built up. Witnesses of these processes-natural geological objects as well as rock, ore and mineral samples-are collected in the Pre-Cambrian Geology Museum of the RAS Karelian Research Center.
BEGINNING
This museum, founded in 1961 — in fact simultaneously with the Geology Institute of the Karelian Branch of the USSR Academy of Sciences and headed by Viktor Yudin, Cand. Sc. (Geol. & Mineral.)—was conceived as a repository of geological evidence. Field samples found in Karelia by scientists of the Geology Institute and other research bodies made up its initial collection which has grown to more than 3.5 thous. items. Displayed in two halls, they are an ocular demonstration of the mineral wealth of our land and show the record of geological studies begun nearly 300 years ago with the discovery of iron and copper ore deposits, and a chalybeate water spring detected in 1714 about 50 km northeast of Petrozavodsk.* All that gave an impetus to further exploration. But regular prospecting began only as late as the latter half of the 19th century, largely owing to Professor
* See: N. Chikina, "Healing Waters of Karelia", Science in Russia, No. 2, 2010. -Ed.
Platon Puzyrevsky of St. Petersburg University, Grigory Hälmersen (elected to the St. Petersburg Academy of Sciences as full member in 1844), Alexander Inostrant-sev (elected to the St. Petersburg Academy of Sciences as corresponding member in 1901), and Franz Levinson-Lessing (elected to the Academy of Sciences of the USSR in 1925).
This work was carried on by Acad. Alexander Polkanov, the organizer and first director the Karelo-Finnish Research Base of the Academy of Sciences of the USSR (subsequently, the Karelian Research Center of the Russian Academy of Sciences) and by Dr. Pyotr Borisov, the first director of our research institute. These two men laid a groundwork of modern geological surveying. Geologic mapping moved to the fore soon after the Second World War; these studies were carried out by Kauko Krats (elected to the Academy of Sciences of the USSR as corresponding member in 1968), Dr. Vladimir Sokolov, and Dr. Galina Biske, known for her geomorphology studies.
The 1998 to 2003 years were a landmark stage in our museum's life. Its exposition was overhauled and enlarged at the initiative of Dr. Sergei Rybakov (heading the Geology Institute between 1986 and 2000), with the support of the Ministry of Natural Resources of the Republic of Karelia, and the Association of Mining Industrialists. As a result, our museum changed beyond recognition—a small showroom became a large public educational center playing host each year to as many as 2.5 to 4 thous. guests—homeland experts and their foreign colleagues, tourists, school pupils, and just plain lovers of nature. Our staffers conduct guided tours of natural field objects and make lectures on Pre-Cambrian* geology; they coach undergraduates of Petrozavodsk State University majoring in geology and mineralogy.
* Pre-Cambrian-designating the geologic time before the Cambrian Era: it is now divided into the Archeozoic and Proterozoic Eras taking in the time span between the earliest geology of the earth (3.9 billion years ago) and the appearance of the first multicellular organisms (ca. 570 million years ago). -Ed.
Making a tour of our halls, visitors can see how the evolution of the Karelian craton (stable trend of the continental crust) was proceeding within the Fennoscandi-navian shield in the Archean (3.3 to 2.5 bln years ago) and in the Proterozoic (2.5 to 1.6 bln years ago). They can learn about Karelian volcanoes and their eruptions, if any; about ancient bodies of water and precipitation feeding them. And last and not least: our guests will get to know what happened to Karelia's topography in the Quaternary period (the present stage in the evolution of the earth setting in 2.5 mln years ago and still going on).
MYSTERIES OF OLD VOLCANOES
At first glance they look quite nondescript, all the various rock fragments, bits and pieces of igneous breccia, blister or pillow lava—almond-shaped and emeraldgreen angular debris, each 1 cm and more in size, and fused together. Such structures, no matter when and where found—on land or at sea, and dating to different geological times-are definitely of volcanic origin.
These structures first appeared around 2.9 bln years ago to form an Archean crust and give birth to a new line in Pre-Cambrian geology—paleovolcanology (from the Greek palaios, or old, ancient), with Dr. Anatoly Svetov making a signal contribution to the progress of this discipline. He has upgraded the methods of Pre-Cambrian reconstructions and mapped early Pre-Cambrian complexes for the Karelian region and the Fennoscandi-navian shield at large.
Exploring ancient formations north of the community of Girvas (Kondopoga district) in 1966, Dr. Svetov came upon rocks of complex structure in the catchment area of the Paleo Ozero hydraulic power station; later on
Chalcedony (a), agate (b), carneol (c) and amethyst (d) filling lava hollows and occasionally, those in sedimental rock in the Lake Onega area.
these rocks were named a Girvas volcanic edifice (structure), or just Girvas Volcano. Today it is a natural monument of federal significance much popular with tourists and guests to Karelia, though they cannot see much, just the volcano's eruptive vent funnel (neck), the southeastern slope of its lava cone and, possibly, the diatreme, or volcanic pipe. The rest is buried under a thick mantle of loose lacustrine and alluvial sediments of the Quaternary period. This volcano, about two billion years old, is one of the incurrent canals of a vast lava or volcanic plateau in a large area west of Lake Onega.
In the late Paleoproterozoic (ca. 1.97 billion years ago) a string of similar geologic structures stretching along the shore of Lake Onega formed the topography of the environs of Petrozavodsk* and the community of Solomen-noye** close by. At that time this was the scene of vigorous volcanic processes and explosions giving rise to breccias, or clastic rocks formed with the ejection of lavas and tuffs, and dubbed Solomennoye rocks. Small cavities in hardening lavas and occasionally in sedimental rocks were being filled in, a process accompanied by decrystal-lization of young minerals precipitating from hydrother-mal solutions. This is how secretions, or hollows of different size, were formed. They were filled with such minerals as agate, chalcedony, amethyst, red carneol, quartz, calcite...
In those days the Paleocean covered nearly the entire surface of the earth, with "islets of land", the continents, submerging every now and then, and accumulating sediments that retained structures typical of wave-cut areas. Such structures are well identified in Paleoproterozoic quartzitic sandstones, 2.3-1.7 bln years old, in the form of stratified, obliquely laminated rhythms and wind-ripples. Desiccation fissures, the proof of shallow waters, are often visible in them. The accumulation of sediments was proceeding against a background of vigorous volcan-ism throughout all the geologic epochs of the Pre-Cambrian.
PALEOSEA'S FROZEN WATERS
Our museum boasts of a rich collection of stroma-toliths, products of the vital activity of blue-green algae which appeared in Finnoscandinavia in the Paleoproterozoic, or about 2.3 bln years ago. Two geologists, Vladimir Makarikhin and Pavel Medvedev, found as many as 500 specimens in a decade between 1980 and 1990; of these, 100 are on display. But the first finds were made back in 1866 by Platon Puzyrevsky in carbonate rocks of the Ladoga area and then in 1906 by Sergei Yakovlev in Belaya Gora (White Mountain) marble deposits at Kondopoga. Initially these stromatoliths were designated as corals, algae, faunal remnants, and what not. It was much later, in the 1960s, that stromaliths were assigned to fossil products of the vital activity of blue-green algae and bacteria. In Karelia five areas of their propagation have been identified thus far.
According to Dr. Medvedev, these mineralized structures were formed from a carbonate material precipitated from a solution in consequence of the metabolic activity of microorganisms (cyanobacteria). Given that the age of the earth is about 7 bln years, paleorocks formed with the precipitation of sand in the primordial ocean must be around 3.8 to 3.5 bln years old. Which means that after a billion years from its birth, our planet came to be inhabited by the first living organisms—one-cell microorgan-
* See: O. Bazanova, M. Khalizeva, "Petrozavodsk Is Famous!", Science in Russia, No. 2, 2009. -Ed.
** See: A. Prokhorov et al., "Gardens on the Rocks", Science in Russia. No. 3, 2009. -Ed.
isms, the prokaryotes (organisms with cells without a discrete nucleus), existing in an oxygen-free medium and leaving fossil traces of their vital activity.*
As a matter of fact, cyanobacteria are still building stromatolithic structures. This occurs, as a rule, under extreme conditions—in high-salinity bodies of water, in deep-water and ground surface hot springs related to vol-canism, that is under the same conditions as those obtained on earth over 3 bln years ago.
SCHUNGITE, THE HARDENED OIL
Black shales, or schungites**, were accumulating in stagnant regions extant in the Ludicovian, one of the periods of the early Pre-Cambrian. Such minerals are widely displayed in our museum. These rounded, "drop-like" formations of shiny black anthraxolites have now been found to be hardened, solidified oil. A sensational discovery!
The first samples of this native mineral were detected in the beginning of the 18th century near the community of Schunga, one of the oldest and largest settlements west of Lake Onega. They were dubbed Olonets chernozem (black earth), because found in what was then the Olonets Province. Schungites proved a good organic fertilizer and were also used for making black dye. Their outcrops were first described by Academician Nikolai Ozeretskovsky of the St. Petersburg Academy of Sciences, a natural scientist, as far back as 1792. Later on, in 1842, Staff-Captain Nikolai Komarov of the Corps of Mining Engineers, hit upon large accumulations of "resinous rock". Grigory Hälmersen, who inspected them in 1860, came up with a batch of definitions: "black slate", "loose coaly matter", "clayey slate abundant in graphite"... Towards the end of the 1870s the "schungite anthracite" was found to be good for use as fuel in the Navy.
Black shales were commonly believed to be no more than coal. Just like that. But Alexander Inostrantsev proved they were more than that. Examining their samples in 1877 and 1879, he pinpointed their position as one being "the last in the amorphous carbon series" in his General Course of Geology (1885). He coined this term, "schungite".
Today this name holds for a large group of black Pre-Cambrian rocks containing as much as 45 to 80 percent of the carbon-bearing substance. Different in look, in mechanical and chemical characteristics, they are finding ever wider hands-on uses. Many of their varieties have found application as a useful mineral in industry, namely in pyrometallurgical and chemical processes.
In the 1890s fullerene molecules***—hollow carbon "buckballs" of 60 and more atoms—were detected in
* See: V. Parmon, "Autocatalysis: Go-Ahead to Life?", Science in Russia, No. 4, 2004. -Ed.
** See: Yu. Kalinin, "Ecological Potential of Schungite", Science in Russia, No. 6, 2008. -Ed.
*** See: B. Volter, "Dynamic Systems and a 'Singing Heart'", Science in Russia, No. 6, 1997. -Ed.
Anthraxolite (schungite) and fullerene structure.
Iron minerals and iron ores of Karelia: limonite crustal (a), "monetalia" (b), hematite (c), magnetite, or ferruginous quartzites (d).
these compounds. Owing to their reticular-spherical structure (a sphere composed of penta- and hexahedrons), these molecules proved ideal fillers. Combining different atoms and molecules within, one can create truly fantastic materials of the future for nanotech-nologies, medicine, electronics, optoelectronics and other high-tech fields.
Schungite and schungite-containing rocks are found in a large area of about 10 thous. km2 stretching toward Lake Onega (south of Petrozavodsk to the river Pazha in the north, the community of Girvas in the west, and the community of Tolvuya in the east). These deposits are big enough for industrial uses.
ORE MINING
The upper floor of our museum features a brief history of geologic explorations in our land; one section deals with the record of ore-mining industries in the former Olonets Province.
The founding of the new Russian capital, St. Petersburg, early in the 18th century and the growing might of the Russian army made it imperative to explore for iron and copper ore deposits. Here in Karelia this job was being done by common people, the ore-hunters. In keeping with a Petrine ukase (decree) issued in 1702, one such native prospector, Ivan Patrushev, headed a secret expedition to see what could be done for founding ore-smelting enterprises. The first ore-smelter was set up in 1703 in the mouth of the Lososinka, to be followed by yet another four foundries and smelters known as the Petrine works; they utilized crustal and cavernous limonite* (marsh or bog) ores. A century later hematite,** or specular iron ore, came into use.
The post-World War II years saw the discovery of major magnetic anomalies with indigenous deposits of ferruginous quartzites, the magnetic iron ores (lodestones). The largest deposit, at Kostomuksha (lying 480 km from Petrozavodsk), is estimated at 1,400 mln tons.
The iron ore accumulation process is still on. The excess of iron in water leaves rusty stains on grass, ground
* Limonite (brown hematite)-of a group of iron hydroxide minerals. -Ed.
** Hematites—minerals of simple iron oxide subclass. -Ed.
Copper nuggets of Onega.
White Sea land minerals: muscovite (a), moonstone (b), graphic concretion ofoligoclase and quartz (c), almandine (d), fuchsite (e), ruby (f).
and even tableware. Its sediments build fantastic limonite tubules on tree roots. Flat plaques looking like regular coins come up on small stone fragments; hence the name, metalla monetalia. Our collection contains exotic forms of these minerals.
But chalybeate waters may be of good use, too. One such medicinal water spring is 50 km from Petrozavodsk; by Petrine ukase the first Russian spa resort, Martial Waters, was opened there in 1719. In iron content it is superior to all other mineral springs in this and other countries. The health element is present there in the bivalent form well ingested by the organism.
The work to survey for and mine sulphide copper and complex ores began as early as the 18th century. Native copper deposits were discovered then in the Onega Lake area (though archeologists say copper had been used in ornaments all the way back in the 3rd century B.C.). Russia's first gold was found in 1737 near the community of Nadvoitsy (Segezha District of Karelia). One such specimen has been on display in the Vienna Museum of Natural History since 1827.
Most of the ore mines and enterprises of the 18th century were located north of Lake Ladoga. Surveying skarns (rocks formed at the marble/granite interface under the effect of solutions coming off from granites) with reddish-brown, black and salad-green garnets, andradites and melonites, geologists found cassiterite SnO2, a tin mineral, though the original purpose was to look for copper and lead. A medal cast from this mineral is on display in our museum as a remembrance of old-time mining technologies.
Towards the close of the 19th century undergraduates of two universities, of St. Petersburg and Helsinki, began practical studies of skarn mineralogy at Platon Puzyrevsky's initiative. Even in this day and age these natural objects are much in favor with young geologists during their field practicals.
WHITE SEA LAND MINERALS
Mineral samples of northern Karelia, a land south of the White Sea coast, make up the most fascinating part of our collection; these are roseate rubies, crimson almandines (almandites), emerald-green fuchsite, cyan-ite, staurolite, amethyst...
We keep a collection of pegmatites in the form of in-block and graphic concretions of plagioclase and quartz, and also plagioclase crystals of fender iridescence (optical rainbow effect) caused by inner light refraction. Acad. Alexander Fersman (1883-1945)*, one of the founders of geochemistry, who traveled north at the turn of the 20th century, called this mineral belomorite (of the White Sea), otherwise known as moonstone. Extracted from pegmatites were big crystals of sheet mica, the muscovite, used in Old Rus as window glass. Today this material has technical applications, e.g. for insulation.
The wonderful skeletal crystals of apatites are striking in their extraordinary case-like shape. Such minerals
* See: R. Balandin, "Poetry in Stone", Science in Russia, No. 6, 2003. -Ed.
with plagioclase "filling" are featured also in other geological museums of Russia.
THIS HOMEY NATIVE STONE
Outcroppings of indigenous rocks in the Lake Ladoga and Lake Onega area as well as the beauty of local skär-gårdar (skerries) made this territory attractive for settlement and for building monasteries, churches and sketes (monastic sanctuaries). Gray Serdobol granite quarried near the town of Serdobol (Sortvala now) on isles in the northern part of Lake Ladoga was used for the purpose. Local kinds of trim stone-the rare striated black-and-white marble found in the village of Joensu as well as marbles of different shades and hues were taken by water to St. Petersburg to finish and decorate its palaces. Tsar Peter ordered that everybody coming to St. Petersburg from quarries should bring in several "stone pieces".
The Ruskeala marble deposit on the northwest shore of Lake Ladoga (32 km from Sortvala) has been known since the 18th century. In 1768 Empress Catherine II signed a ukase whereby marble and native stone should go for the building of a St. Isaac Church at Keksholm; grinding mills were to be set up for stone working. The active use of the Ruskeala deposit began then and there. The variegated local stone (from dark-and-gray and black to starch white) played an extraspecial role in decorating St. Petersburg's architectural wonders. It was used in facing the St. Isaac and the Kazan Mother of God Cathedrals, the Engineering Palace and the Russian Museum, and in lining the interiors of the Winter and Marble Palaces. Today the mountain park "Ruskeala" has been laid out in the quarry's canyon where one can come upon what remains of the old drifts and mines; this is a monument of industrial mining culture covering a period from the late 18th to the early 20th centuries. The oldtime opening filled with emerald-green water, against a backdrop of snow-white cliffs, is a major attraction to experts and lovers of nature alike.
Ashlar rocks: Ruskeala and Tivdia marbles (a-d), rapakivi granite (e), gray Serdobol granite (f), garnet amphibolite (g), migmatite granite (h).
Shokshu quartzite.
Six varieties of marble were being mined in a quarry near the community of Tivdia (62 km northwest of Kondopoga). This marble was once called belogorsky, after the Belaya Gora (White Mountain) deposit discovered in 1757 by Ivan Martyanov, a merchant. Learning about that, the then ruling Empress Elizabeth sent workhands there, and ordered to start marble mining and working at the earliest date. In his travel notes about Lakes Ladoga and Onega (1785) Nikolai Ozeretskovsky described in detail the stone-crushing technology. The Tivdian stone, rich in a great variety of shades (more than thirty, from pale-roseate to lilac), was used along with the Ruskeala marble to decorate edifices and palaces in St. Petersburg, and in its suburbs, Petershof and Tsarskoye Selo. However, in the latter half of the 19th century the industrial quarrying of White Mountain marble phased down and came to a stop by the turn of the 20th century.
Indigenous stone decorates the interiors of our museum, too. For instance, the floor in the lower hall of our museum is a spectacular mosaic of marble slates coming from the Kondopoga stone-working mill.
Crimson quartzitic sandstone quarried since the end of the 18th century at Shoksha next to Lake Onega is quite popular as facing material thanks to its bright color given by minor impurities of ferric oxide; this color is enhanced during stone polishing. This lovely red stone is there in many buildings and memorial complexes of Petrozavodsk, the capital of Karelia, and in the St. Isaac Cathedral of St. Petersburg, the Lenin Mausoleum in Moscow, and the Napoleon tomb in Les Invalides Church in Paris.
Silanite, or smelt rock, is also much in demand. Our museum offers a wide range of silanite applications in the glass-making, ceramic, chemical and other industries.
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