The Maksovo metasapropelite deposit, which contains shungite matter and is called maksovite, is located in the eastern Onega structure. The deposit is a diapiric fold which formed ca. 2070±10 Ma ago. It is underlain by carbonate rocks and overlain by tuff siltstones and is cross-cut by 1956±5 Ma gabbro-dolerites. Unaltered maksovites are pelitomorphic rocks with a massive to mildly layered texture and moderate concentrations of all petrogenic components and Сorg of about 30%. Fe-Mg rich and alkaline metasomatic rocks evolve after maksovites and mafic and carbonate tuff siltstones in the northwestern part of the deposit within a multiple ridge-like fold after brecciation zones. They differ from unaltered sedimentary rocks in heterogeneous (brecciated, streaky) textures, mineral and chemical composition and are saturated with numerous sulphide, carbonate, quartz and albite veinlets. They are identified by intense biotitization, chloritization and the presence of calcite, microcline metacrystals, albite-carbonate metacrystals with apatite and carbonate-quartz metacrystals with sulphides and rutile, veinlets and disseminated mineralization. Na concentration rises to 5.67% and K concentration to 7.57%. P and Ti concentrations, accompanying alkaline metasomatism, as well as Mg-Fe and ore-bearing components (often incompatible), increase locally. Metasomatic rocks evolve heterogeneously and are represented by breccia zones. Their slightly elevated radioactivity disturbs the qualitative characteristics of primary maksovite as a useful mineral. Maksovites were dated at 1558±61 Ma by the Re-Os method from sulphides.

Максовское месторождение метасапропелитов (максовитов), содержащих шунгитовое вещество, расположено в восточной части Онежской структуры — бассейна, заложившегося и формировавшегося в палеопротерозое в юго-восточной части Фенноскандинавского щита. Залежь максовитов представляет собой диапировую складку, сформировавшуюся около 2050±10 млн лет назад; она подстилается карбонатными толщами, перекрывается туфоалевролитами и прорвана габбродолеритами (1956±5 млн лет). Неизмененные максовиты — это пелитоморфные породы с массивной или неяснослоистой текстурой, с содержанием Сорг около 30%. Наложенные на максовиты и на подстилающие толщи туфоалевролитов изменения развиваются в пределах гребневидной складки по зонам брекчирования. Эти изменения представлены щелочно-железо-магнезиальными метасоматитами с брекчированными текстурами, неоднородным минеральным и химическим составом; выделяются по интенсивной биотитизации, хлоритизации, развитию альбит-карбонатных с апатитом и карбонат-кварцевых с сульфидами прожилков. В зонах изменения повышается содержание Na, K, Р, Ti, Mg-Fe и рудогенных компонентов. Время формирования метасоматитов, установленное Re-Os методом по сульфидам — 1558±61 млн лет.

The Maksovo shungite-bearing metasapropelite (maksovite) deposit is located in the eastern part of the Onega Basin that was initiated and formed in the Paleoproterozoic in the southeastern Fennoscandian Shield. The maksovite deposit represents a diapiric fold formed about 2050 ± 10 Ma ago. It is underlain by carbonate sequences and, in turn, overlain by tuffaceous siltstones and intruded by gabbro-dolerites (1956 ± 5 Ma). Unaltered maksovites represent pelitomorphic rocks with a massive or obscure-layered structure containing about 30% C org . Alterations superimposed on the maksovites and underlying tuffaceous siltstone sequences are developed along brecciation zones within the ridge-shaped fold. The alterations are represented by alkaline Fe–Mg metasomatites with brecciated structures, as well as heterogeneous mineral and chemical compositions. They differ in terms of intense biotitization, chloritization, and development of the apatite-bearing albite–carbonate and sulfide-bearing carbonate–quartz stringers. Alteration zones are enriched in Na, K, P, Ti, Mg, Fe, and other ore components. Based on the Re–Os dating of sulfides, the age of metasomatites is estimated at 1558 ± 61 Ma.

The sequence of interrelated events - from accumulation to secondary concentration and dispersion of organic matter characterizes the unique phenomenon of "Shunga" for Paleoproterozoic, most fully investigated in the Onega sedimentary basin. The main stage is the accumulation of huge volumes of primary organic matter, as well as the subsequent stages of its redistribution of numerous domed and subplastic local bodies of high-carbon rocks with characteristic differentiation of composition; various forms of anthraxolite manifestation, indicating the implemented full-scale process of hydrocarbon generation, numerous types of collectors, indicating their migration; traces of decomposition of both primary and newly formed organic matter. In the review, on the example of the Franceville basin, the evidence of the existence of all stages of the phenomenon in analogs, in which the main stage developed synchronously, is presented. The results of dating deposits of the two basins are analyzed in detail, fundamental errors in the interpretation of geochronological data are revealed. It is shown that the correlation of Paleoproterozoic sedimentary basin sections is possible by geochemical marking horizons with delta(13)Corg anomalies and high content of U, Mo, Se, As, Ni, V.

Обсуждены особенности реакций стрессреализующих систем организма в покое и при выполнении соревновательных упражнений ветеранами гиревого спорта. Фоновая активность коры надпочечников у ветеранов повышена, что обусловливает гипертензивные эффекты, а также снижение реактивности респираторных ответов. При выполнении упражнений у них более низкая, чем у молодых, эффективность приспособительных реакций внешнего дыхания, о чем свидетельствуют меньшие значения резервных объемов вдоха и выдоха, а также энергетически неэкономная реакция надпочечников и более низкая эффективность приспособительных стресс-реакций.

Significant accumulation of autochthonous organic matter preserved in Palaeoproterozoic rocks is rare. One of the largest and most remarkable occurrences is the deposit at Shunga, in Karelia, northwestern Russia. This enormous accumulation of C-rich rocks is part of the world-wide Shunga Event. The integrated data suggest that the OM was most likely derived from planktonic microorganisms. This remarkable accumulation of OM and inferred generation of giant volume of petroleum took place in the aftermath of the ca 2330–2060 Ma Lomagundi—Jatulian Event—the largest positive excursion of δ13Ccarb of sedimentary carbonate in the Earth’s history. The formation of shungite carbon and its diagenetic, catagenetic and metamorphic transformation are related to fundamental problems of biological evolution, global carbon cycle and the earliest oil generation.

Occurrences of 2.0 Ga, mature organic material from the Lake Onega area, NW Russia, constitute one of the most remarkable accumulations of organic carbon from the Palaeoproterozoic. The deposit occurs in a 1000-m sedimentary-volcanic succession developed over an area of 9000 km(2) with an estimated total carbon reserve exceeding 25 x 10(10) tonnes. The organic material occurs in the form of the mineraloid, shungite, which is a black, non-crystalline, semi-metallic material that contains >98 wt.% C.The shungite-bearing rocks were accumulated within a volcanic continental rift setting, in a non-euxinic, brackish-water, lagoonal environment developed on the rifted margin of the Archaean craton. The occurrences of shungite-bearing rocks represent a combination of a petrified oil field, petrified organosiliceous diapirs and oil spills. These are exemplified by three types of deposit: (i) in situ stratified, (ii) migrated diapirs and (iii) redeposited elastic. In situ stratified deposits are composed of metamorphosed oil shales (<50 wt.% Q, rocks containing autochthonous kerogen residue and allochthonous organic matter (50-75 wt.% C and migrated bitumen, originally liquid hydrocarbons (>80 wt.% C. Diapiric deposits form non-stratified, cupolas or mushroom-shaped bodies composed of shungite containing 35-75 wt.% SiO2 and 20-55 wt.% C. These are considered to represent organosiliceous rocks, originally gels or mud. The shungite rocks show abundant shrinkage cracks, cryptic fluidal textures and brecciation caused by multiple fluidisation processes. The current data are consistent with either diapiric or mud-volcanic origins. Occurrences of elastic shungite are hosted by lactistrine volcanoclastic greywackes deposited from turbiditic flows. Shungite occurs in rocks as < 1 mm to 20 cm clasts of lustrous shungite that probably represent redeposited, oxidised oil derived from oil spills.Shungite has a heterogeneous molecular structure in which carbon occurs as 10 nm globules irregularly distributed within carbon showing no structure. The unusual physicochemical and structural properties of shungite are used in diverse industrial and environmental applications including metallurgy, water purification, thermolysis and organosynthesis of cyclic hydrocarbons. Shungite is an effective sorbent for removal of organic and inorganic substances, pathogenic bacteria and heavy metals from contaminated water. (C) 2003 Elsevier B.V. All rights reserved.

The ca. 2.0-Ga-old, 600-m-thick upper Zaonezhskaya Formation near Lake Onega, NW Russia, contains unusually high concentrations of Corg (up to 98%), averaging around 25%. The formation contains an estimated 25×1010 tonnes of organic carbon accumulated within an area of 9000 km2. Organic material is represented by shungite, which forms a black, dense, amorphous or nanocrystalline mass consisting of C with traces of N, O, S, and H. Autochthonous shungite occurs as disseminated organic material (0.1–50% Corg) which, when mixed with migrated bitumen (now pyrobitumen), appears as coal-like seams and lenses of semilustrous and semimat layer-shungite rocks (oil shales, 50–75% Corg). The migrated bitumen (originally petroleum), represented by the lustrous vein- and layer-shungite, conformably fills interbedding spaces or cross-cutting joints and usually contains 80–98% Corg. The shungite-bearing rocks of the upper Zaonezhskaya Formation represent one of the most richest accumulations of organic material reported from the Palaeoproterozoic, and one of the geologically earliest stages of petroleum generation. The sediments of the Zaonezhskaya Formation were initially deposited in brackish water in a non-euxinic, lagoonal environment. The high C/S ratio (8–1000) with a zero intercept on the C–S cross-plot indicates that deposition occurred in sulphur-poor water. Intensive synchronous volcanism may have contributed to both the enhanced delivery of nutrients and elevated sedimentation rate, and eventually to the high degree of preservation of organic material. The integrated data suggest that the organic material has a biogenic origin, most likely algal or bacterial. The organic material suffered complex catagenetic and metamorphic alteration which is reflected in: (1) the four-modal distribution of Corg content (with maxima at 5, 30, 65 and 95%); (2) highly variable δ13Corg (−45‰ to −17‰); (3) bimodal distribution of δ13Corg (with maxima at −28 and −39‰); and (4) low H/C ratios (0.005–0.2). Abundant diagenetic carbonates associated with shungite rocks (δ13Ccarb=−5 to −26‰) and the presence of pyrite (δ34S −22 to +31‰), reflects substantial loss of organic matter via bacterial reduction of sulphate during diagenesis. The shungite rocks are characterised by a further substantial loss (>50%) of biologically produced organic material in the course of thermal maturation and by a depletion in 12C (>10‰). The isotopic composition of carbonate concretions does not indicate the involvement of fermentative diagenesis. Conservative estimates give δ13Corg of −34‰ as the best value of the initial biomass. Lustrous vein- and layer-shungite containing more than 80% Corg are considered to be allochthonous, migrated bitumen (originally petroleum). The semilustrous and semimat layer shungite rocks containing 55–75% Corg represent oil shales with both migrated bitumen (originally petroleum) and autochthonous kerogen residues. The oil source rocks were apparently hosted in the Zaonezhskaya Formation. The generated oil has migrated both vertically and laterally with the highest concentration in cupola structures. The locality at Shunga represents the most significant volume of trapped petroleum from the study area.