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Vol. 10 (2007 year), No. 1
Nikitina L.P., Ovchinnikov N.O., Babushkina M.S., Yakovleva A.K., Yakovlev Yu.N., Chernova O.G., Goilo E.A.
Do Fe-Mg micas from the Archaean rocks of the Kola Superdeep Borehole preserve information about the crystalline substance state during their extraction to the surface in the course of drilling?
A comparative analysis of structural and spectroscopic peculiarities of the rock forming minerals in the SG-3 rocks and their homologues in the Pechenga structure framing allowed obtaining some new results concerning the specific character of buried Archaean units and constructing correlations between deep and surface formations. The investigations were performed with the use of the EPR data on vacancy defects (Р•1-centres) and defects related to the isomorphous incorporation of Al-, Ge-, Ti-ions into the lattice of the rock forming quartz and the X-ray luminescence (XRL) data on the proper and admixture defects in plagioclase. Rank correlations between the qualitative composition of the plagioclase XRL patterns and petrogenetic characteristics of host rocks have been found. Dependence of the system of admixture and proper structural defects in the rock forming minerals along the SG-3 section vs the depth of occurrence and petrogenesis of the Precambrian host rocks has been estimated. Our study showed that the admixture structural defects in the rock forming quartz can serve as a genetic mark of metamorphic rocks in the Precambrian structural-formational complexes. They are one of the criteria for typization and correlation of deeply metamorphosed Early Precambrian units penetrated by SG-3.
(in Russian, стр.13, fig. 8, tables. 6, ref 34, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 1
Nikitina L.P., Babushkina M.S., Chernova O.G., Ovchinnikov N.O., Yakovleva A.K., Yakovlev Yu.N., Goilo E.A.
Structural state of amphibole from the Archaean rocks of the Kola Superdeep Borehole and their homologues at the surface
Trioctahedral ferromagnesium micas from the SG-3 Archaean rocks and their surface homologues constituting the amphibolite-gneiss complex in the Pechenga structure southern framing (Allarechka block) have been studied. The mineral structure, the nature and degree of structural defects have been investigated by X-ray powder diffractometry, infrared and Mossbauer spectroscopy. The chemical composition of micas was determined by the wet chemistry and microprobe methods. The study showed that with the same fm values, the mica structures from the SG-3 Archaean rocks have higher values of the unit cell volume over those for synthetic micas of the phlogopite-annite series. This is evidence of the mica structural "looseness" and is unexpected for a mineral from deep zones (7900-11350 m) taking into account the presence of trivalent cations to 0.5 AU in the mica octahedral layer. The presence of defects related to the composition non-stoichiometry (the presence of crystalline hydrate water molecules in the alkaline cation site and availability of vacancies in the octahedral sites M1) and defects of "order-disorder" type have been established. Non-stoichiometry of the composition is equally typical of the micas from the SG-3 Archaean rocks and surface homologues and is likely to reflect the metamorphism specific regime of the Archaean complex under amphibolite facies conditions (increased partial water pressure, lack of alkalies). At the same time the content of crystalline hydrate water molecules in the mica structure from the SG-3 Archaean rocks decreases slowly with depth. A various degree of cation order in the octahedral sites of the mica structure from the SG-3 Archaean rocks (disorder or close to disorder distribution) and from the homologous rocks (order distribution with prevailing ferrous iron occupation of the sites M1) has been established. The difference in the order degree most likely results from the different velocity of the Archaean rocks lift in the process of drilling as well as from the erosion processes. This fact supports the assumption that some structural peculiarities of minerals do not alter when extracting the core from the borehole. This provides preservation of the information on the crystalline substance state at depths of the Archaean complex cut by the borehole.
(in Russian, стр.11, fig. 3, tables. 8, ref 13, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 1
Skufin P.K., Lyutoev V.P., Yakovlev Yu.N., Smirnov Yu.P., Glukhov Yu.V., Kotova E.N.
Properties and structural peculiarities of rock forming minerals and Early Proterozoic sedimentary rocks in the SG-3 section and their homologues at the surface
Actinolites and hornblendes from the SG-3 Archaean rocks and from the surface Archaean complex (Allarechka block) have been studied. The Allarechka block used to be considered a surface analogue of the SG-3 Archaean complex. The mineral structure, the nature and degree of structural defects have been investigated by X-ray powder diffractometry, infrared and Mossbauer spectroscopy. The chemical composition was determined by the wet chemistry and microprobe methods. The comprehensive investigations resulted in establishing composition stoichiometry of deep and surface amphiboles. Vacancies are present only in rare samples and in minor amounts. The majority of the studied amphiboles had a high degree of the unit cell deformation and its elongation along the c axis. A high and about the same degree of Fe2+ and other cations was observed in both groups of specimens. At the same time the patterns of the site occupation by Fe2+ are slightly different: Fe(M3)>Fe(M2)?Fe(M1) – for deep samples and Fe(M3)>Fe(M1)>Fe(M2) – for surface ones. The degree of iron oxidation is established to be similar (from 5 to for 20 %) for both surface and deep samples. Actinolite and low-alumina hornblende have no marked difference in their structural state at a depth of 7900-11350 m and at the surface. The data on the crystalline substance state at the crust deep zones may be useful for reliable interpretation of geophysical measurements, development of correct models of the crust structure and for choosing the proper sites for disposal of radioactive wastes. The structural state of amphibole (actinolite, low-alumina hornblende) from amphibolite and crystalline schist of the SG-3 Archaean complex and their surface homologues has been studied. The aim was to elucidate whether the structural state of those amphiboles differs and whether the amphiboles from the SG-3 Archaean rocks preserve any information about the physical state of the crystalline substance at great depths during their extraction to the surface. We have studied the composition, degree of iron oxidation, nature and degree of structural defects and the availability of various forms of water in the structure of amphiboles from the SG-3 Archaean rocks (7930-11330 m) and their surface homologues from the Allarechka block (southern framing of the Pechenga structure). According to the modern nomenclature (Leake, 1997), the actinolite and hornblende pertain to the calcic amphibole group.
(in Russian, стр.19, fig. 11, tables. 8, ref 25, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 1
Yakovlev Yu.N., Skufin P.K.
Ore mineralization of Proterozoic rocks from the lower volcanic formations in the SG-3 section and their homologues in the near-surface zone
Inclusions in zircon of magmatic and metamorphic genesis from biotite-plagioclase gneiss in SG-3 Archaean unit VIII have been studied. A criterion of magmatic zircon genesis is the presence of melted inclusions in them, the study of which allows determining the composition and evolution of the primary melts. The study of the inclusion composition showed that crystallization of plagiorhyodacitic melts started with formation of micro grains of potassium-bearing plagioclase (Ab61, An26, and Or13) and titanomagnetite. At the same stage zircon grains were likely to be formed. Some of them trapped liquid СО2 inclusions and syngenetic melted inclusions. The presence of such inclusions points to crystallization of early zircon from СО2-saturated magmas at P ~3.5 kbar. During metamorphism of plagiogneiss protoliths, isometric crystals of zircon cut in a complicated manner were formed. They contained primary inclusions of chloride solutions similar to those in plagioclase and quartz from plagiogneiss. The fluid pressure, assessed by inclusions of water solutions and СО2 rich inclusions in the zircons under study, reached 2.8-4.0 kbar at Т = 540-620°С.
(in Russian, стр.16, fig. 0, tables. 10, ref 12, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 1
Bayanova T.B., Yakovlev Yu.N., Guberman D.M., Yakovleva A.K., Skufin P.K.
Isotopic investigations of age of the Archaean rocks from the Kola Superdeep Borehole section, Proterozoic Pechenga structure and its framing.
The results of the study of ore mineralization in the rocks from the three lower volcanic formations in the SG-3 Proterozoic complex and in their near-surface homologues cut by the structural boreholes IX and X have been presented. Sulfide specialization of volcanites from the Majarvi Fm has been found. Oxide specialization of rocks from the Pirttijarvi and Orshoaivi Fms has been confirmed. The distribution, evolution conditions and chemical composition of sulfides and oxides from volcanites have been studied. The main features of development, composition and late alterations of ore minerals could be related to two factors. The composition of sulfide from the Majarvi Fm vulcanite and oxide from the Pirttijarvi and Orshoaivi Fms in the SG-3 section is determined by a "depth factor" that caused a widespread occurrence of mineral solid solutions. Intense development of hematite and transformation of magnetite and ilmenite in volcanites of the Pirttijarvi and Orshoaivi Fms in the SG-3 section are explained by the influence of the regional Luchlompolo fault. High contents of isomorphous admixtures – PGE, Se and Co in sulfides, V, Ti and Mn in oxides that were not observed earlier in the SG-3 section and geoblock as a whole have been established in all major minerals from the formations deep levels.
(in Russian, стр.12, fig. 9, tables. 3, ref 29, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 1
Gordienko V.V., Gordienko Vl.Vl., Kalinicheva G.I., Olkhovaya E.A., Rumayntseva E.V., Timokhina L.A., Guberman D.M., Smirnov Yu.P., Yakovleva A.K., Yakovlev Yu.N.
Granitic pegmatite of the Kola Superdeep Borehole (vertical mineral-geochemical zoning and genesis problems)
The basement of the Early Proterozoic Pechenga palaeorift was penetrated by the Kola Superdeep Borehole (SG-3) at a depth of 6842-12262 m. In contrast to similar rocks framing the Pechenga palaeorift, Archaean rocks of SG-3 were affected by Proterozoic magmatism and metasomatism related to the rift development. The most intense Proterozoic processes were an intrusion of numerous mafic-ultramafic bodies, retrograde metamorphism and synmetamorphic migmatization, and emplacement of postkinematic granites. Most Proterozoic processes were determined to have been related to mantle sources. The overall amounts of Proterozoic material introduced into the Archaean rocks penetrated by the lowermost part of SG-3 coupled with the remobilized material of the Archaean crust is estimated at ?30 % (?12-15 % amphibolites, ~3 % granite veins, ~15 % migmatized rocks). Thus, searching for homologues to the SG-3 Archaean rocks does not lie only in a quest of analogous rocks in the frame of the Pechenga structure, but in the interpretation of the Proterozoic processes that have changed quantitative ratios and composition of the palaeorift basement rocks.
(in Russian, стр.14, fig. 3, tables. 7, ref 11, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 1
Guberman D.M., Larikova T.L., Morozov Yu.A., Smulskaya A.I., Sholpo V.N., Yakovlev Yu.N.
Structure and evolution of the Kola Superdeep Borehole geo-space based on results of the study of structural-material heterogeneities
Some aspects have been shown in the paper: a general characteristic of granite pegmatites cut by SG-3 and data on structural variations of their "end-to-end" pegmatite-forming minerals – feldspar, garnet and mica – depending on the depth of pegmatite occurrence. The existence of vertical geochemical zonality (VGZ) of pegmatite vein system (PVS) of KSDB is proved statistically (more than 300 monomineral samples). VGZ, which has complicated polystage reciprocal character, is caused by contrast migration of chemical elements – indicators (CEI) at free moving of pegmatite-forming environment within the geochemical stages of the system. The range of such migration for PVS from SG-3 achieves more than 3 km along the vertical, which has denied the existing idea about formation of similar PVS "in situ". VGZ is controlled by a pressure drop and temperature gradient. The latter is estimated by two-feldspathic equilibrium at 25?5°C/km. This feature characterizes thermal conditions of the Kola megablock in the Late Archaean that complies with the initial stage of the Baltic shield formation.
(in Russian, стр.17, fig. 15, tables. 1, ref 26, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 2
Skufin P.K., Yakovlev Yu.N.
Geological setting and petrological peculiarities of volcanic rocks from the Majarvi, Pirttijarvi and Orshoaivi Formations in the Kola Superdeep Borehole and in the near-surface zone
The problem of systematics of amphibolite from the Kola Superdeep Borehole (SG-3) Archaean section has been discussed. An integrated petrogeochemical approach allows classifying these rocks with a high degree of reliability and distinguishing among them varieties dated presumably as Archaean and Proterozoic. Proterozoic rocks among the basic rocks in the Archaean section range from 52 to 67 %. Homologues to metavolcanites from the Matert Formation are present among the Proterozoic metamagmatites in the SG-3 Archaean section. This has cast some doubt on the conclusion drawn by N.P. Vinogradova and V.V. Melezhik about the allochthonous origin of the upper layers of the North Pechenga section, including its producing horizons. This is of great importance in terms of metallogeny
(in Russian, стр.25, fig. 5, tables. 13, ref 32, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 2
Yakovlev Yu.N., Skuf'in P.K., Bayanova T.B.
The rhyodacitic porphyry body in the section of the SG-3 Pechenga area (age and ore mineralization)
By geological, geophysical, petrological and isotopic-geochronological data the Archaean complex in the SG-3 section correlates with amphibolite-gneiss complexes of the granite-greenstone area of the Svanvik-Neiden segment located in the Kola-Norwegian block. Plagiogneisses of tonalite-trondhjemite composition, being one of the major components of the SG-3 Archaean complex and the borehole surroundings, include two types. Plagiogneisses of type A are depleted in heavy lanthanoids to a different degree and their ?Nd ranges from +2 to +0.5. Plagiogneisses of type B are rich in HREE, incompatible trace elements and are characterized by negative ?Nd values which is evidence of contamination of the primary melt by the ancient crust material. Amphibolites associated with plagiogneisses are close to tholeiitic basalts of modern oceanic plateaus and Archaean greenstone belts in the trace element composition. By the experimental data, tonalite-trondhjemite melts corresponding to plagiogneisses of types A and B and depleted in heavy lanthanoids to a different degree, formed during metabasic rocks melting at Р ? 10-15 and ? 8 kbar respectively. Model metabasite sources of tonalite-trondhjemite melts that are initial for plagiogneisses of type A are comparable with basalts of modern oceanic plateaus and Archaean basalts of plume origin in the trace element patterns and their indicator ratios. Low Mg# of plagiogneisses excludes the contribution of mantle peridotites in their formation and, hence, does not correlate with subduction oceanic plate. Variations of trace element and isotopic composition of plagiogneisses more likely point to formation of tonalite-trondhjemite melts at different levels of the thickened mafic crust which includes metabasalt material that is heterogeneous in trace element and isotopic composition. The composition peculiarities of amphibolites and model metabasite sources of tonalite-trondhjemite melts suggest that formation of the thickened crust might be caused by accretion of oceanic plateaus.
(in Russian, стр.9, fig. 3, tables. 6, ref 10, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 2
Astrakhantsev Yu.G., Guberman D.M., Diakonov B.P., Pevzner S.L., Troyanov A.K., Yakovlev Yu.N.
Geoacoustic noises in the Kola Superdeep Borehole
The intrusive body of rhyodacitic porphyry having a thickness about 110 m was fixed in the section of the Early Proterozoic Pechenga Complex of the Kola Superdeep Borehole (SG-3) in an interval of 4673.0-4831.6 m. Rhyodacites correspond to the hypersthene-normative calc-alkalic rocks with normal alkalinity oversaturated by Al2O3 and enriched by Fe and Mg. On a set of ore-minerals (oxides – magnetite, ilmenite, hematite, rutile; sulfides – chalcopyrite, pyrite, pyrrhotite, millerite, zygenite) rhyodacites are close to the host-volcanites of the Orshoaivi-Pirttijarvi Suite and host-sediments of the Luchlompolo Suite, but they differ by stability of chemical composition and by deficiency of isomorphic admixtures. They have a high natural radioactivity, which is caused by the increased contents of U and especially Th. U-Pb age of zircones from rhyodacites – 2043+/–18 Ma. Probably, their introduction preceded formation of the Ni-bearing gabbro-wehrlitic intrusives of the Pechenga Area.
(in Russian, стр.5, fig. 6, tables. 0, ref 6, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 2
Guberman D.M., Badalov O.G., Pevzner S.L., Khmelinsky V.I., Yudin E.I., Yakovlev Yu.N.
Monitoring of geofields in the Kola Superdeep geolaboratory: History, experience, basic challenges and results
The results for investigation of geoacoustic noises distribution in a range of 100-5000 Hz along the Kola Superdeep Borehole (SG-3) have been discussed. A geological section cut by the borehole in the interval of 300-6840 m is shown to be dynamically active by parameters of three-component measurements of geoacoustic noises (GAN). When comparing the data obtained at a year intervals, we found a vertical migration of zones of the stressed state of rocks that is fixed by appearance of new GAN local anomalies or disappearance of those found earlier. From the analysis of the GAN amplitude-frequency spectra, gas emission from the rock massif has been observed, in particular, at the zones of tectonic dislocation of the geological environment.
(in Russian, стр.8, fig. 0, tables. 6, ref 6, Adobe PDF, Adobe PDF 0 Kb)
Vol. 10 (2007 year), No. 2
Schulze K.C., Kuempel H.-J., Guberman D.M., Morgachev V.I., Pevzner S.L., Pisarnitsky A.D., Simonova L.A., Smirnov Yu.P., Khmelinsky V.I., Yudin E.I., Yakovlev Yu.N.
Signatures of fluid level variations in the Kola Superdeep and two surrounding boreholes
Modern concepts of the deep structure of the earth crust based on the analysis and generalization of seismic data collected in the past 40 years and the Kola Superdeep Borehole record have been presented. The tomographic model of the Pechenga district has been characterized. Our knowledge of the layered pattern of the earth crust stratification has been updated, the geometry of seismic boundaries has been described more accurately and the crust-mantle boundary under the Pechenga structure has been found to be uplifted.
(in Russian, стр.8, fig. 6, tables. 0, ref 11, Adobe PDF, Adobe PDF 0 Kb)
Vol. 15 (2012 year), No. 2
Vetrin V.R., Yakovlev Yu.N., Chupin V.P.
Sources of the terrigenous material in the formation of metasedimentary rocks of the Archaean basement of the Paleoproterozoic Pechenga structure
The basement of the Paleoproterozoic Pechenga structure was cored by the Kola Superdeep Borehole SD-3 at the depths of 6842-12262 m. It consists of alternating strata of metavolcanic dacite, plagiorhytodacite rocks and high-alumina gneisses; the protoliths of these rocks corresponded mainly to graywackes. Resulting from the examination of zircons from metaterrigenous rocks of the 1st, 3rd, and 9th strata of the SD-3, the detrital, anatectic, metamorphogenic, and contact-metasomatic genetic types have been identified. Detrital zircons include several age groups. The most homogeneous, i.e., comparable to zircons from tonalite gneisses (bottoms of the SD-3 section) and from surrounding rocks, zircons have appeared to be those from gneisses of the deepest 9th stratum. The data on the age of these zircons, along with a poor rounding of the grains, signify formation of the host gneisses' protoliths owing to washing out and redeposition of material. Widening of alimentation areas, which supplied terrigenous material into sedimentation basins, took place during formation of alumina gneisses of the 3rd and especially 1st strata of the section.
(in English, стр.6, fig. 3, tables. 1, ref 14, Adobe PDF, Adobe PDF 0 Kb)