No 3 (2016)
5-26 726
Abstract
It is generalized the data of location in structures and stratigraphic sequences of the Earth lead and zinc deposits following geological-industrial types (GIT): massive sulphide Cyprus, massive sulphide Urals, massive sulphide Kuroko, massive sulphide Filizchay, stratiform lead-zinc сarbonate-hosted, skarn lead-zinc (stratiform, converted to skarns), stratiform lead-zinc сlastic-hosted, lead-zinc vein. According to estimates which were made by the author, during geological history of the Earth, from the Late Archean to the Quaternary it was accumulated at least 17.3 billion tons of ore, containing more than 317 million tons of lead and 600 million tons of zinc.
A. V. Maslov,
G. A. Mizens,
G. M. Vovna,
E. S. Pyzhova,
N. B. Kuznetsov,
V. I. Kiselev,
Yu. L. Ronkin,
A. Z. Bikbaev,
T. V. Romanyuk
27-46 455
Abstract
The data on U-Pb-isotopic ages of detrital zircons from Riphean-Paleozoic and Early Triassic sandstones and geochemistry of shales and mudstones of the Western Urals are discussed. The ages of detrital zircons suggest that the sand material for sedimentary basins existed at the junction of the East European Platform and Urals during more than one and a half billion years, has been brought mainly from the platform. Tectonogenic sands (according F.J. Pettijohn and co-authors) as a part of the Western Urals sedimentary associations play a significant role only in Vendian and in the last third of the Paleozoic. During the rest of the time was dominated cratonogenic sands. According to clay rocks geochemical characteristics during the time from 1750 to 250 Ma, there are unidirectional trend in the composition of the erosion areas: increasing mafic and ultramafic igneous rocks which reached to maximum in Early Permian time.
47-67 396
Abstract
The article is devoted to the fundamental problem of modern fluid geodynamics and fluid geochemistry - clarifying the role of the gravitational factor in the formation of the East European kydrostratisfera sedimentary basin. The features of the Paleozoic depositional, the mechanism and lithologic-hydrogeochemical consequences of the halogenesis processes and uterine brines density convection of Lower Permian evaporite basin into underlying terrigen calcareous Paleozoic and Proterozoic environment. It was found that the exchange-adsorption and exchange-absorption interaction between brine and clastic rocks was been few involved in metamorphism chloride brines. The lithological-thermodynamic studies and balance calculations in the “brine-carbonate rock” system showed that the main role in the formation of multicomponent calcium chloride brines in the sedimentary cover basin, belongs to the processes of metasomatic dolomitization of limestone.
Seismogeodynamics of interaction area of the Baikal rift northeastern flank and Aldan-Stanovoy block
68-81 449
Abstract
The article presents modern structural-tectonic plan and tectonic-dynamic model of the zone of interaction of the most seismicity active northeastern part of the Baikal rift zone (BRZ) and the adjoint system seismogenic structures of the Aldan-Stanovoy block in southern Yakutia, where is marked a series of seismic disasters with magnitude M ≥ 6. The patterns of structure formation and kinematic types of adjoint active faults, which form structural blocks, where accumulate considerable tectonic stress are discussed. The interaction between large tectonic blocks causes a sudden release of stresses, which results in catastrophic earthquakes (M ≥ 6.0) with focal mechanisms of definite kinematic type.
82-111 359
Abstract
Xenoliths in the Early Cretaceous alkali basalts of Makhtesh Ramon basin (southern Israel) are represented by essentially olivine rocks: dunite (usually including clinopyroxen) - 5% of the total amount, lherzolite - 21%, wehrlite - 28%, clinopyroxenite - 34%, gabbro - 12 %. According #Mg = Mg/(Mg + Fe), xenolith rocks form several discrete groups corresponding to the following values #Mg: >0.85 (dunite, lherzolite, some wehrlites), 0.85-0.75 (wehrlite, olivine clinopyroxenite), 0.75-0.65 (olivine clinopyroxenite, clinopyroxenite), 0.60-0.45 (gabbro). Primary mantle rocks are represented by lherzolite, other xenoliths are the products of metasomatism, which preceded and accompanied magma generation. The main minerals of ultramafic xenoliths- olivine slightly enriched by CaO, clinopyroxene with varying content of TiO2 (1-4%), Al2O3 (2-12%), Na2O (0.5-2%) and #Mg = 0.92-0.59, spinelids: chromite (Cr2O3 = 20-38%), Al spinel and titanomagnetite (TiO2 = 10-21%, Cr2O3 = 0.3-8%, Al2O3 = = 1.5-13%, MgO = 2-7%). Rich inTiO2, Al2O3 and Na2O clinopyroxene together with plagioclase, anorthoclase, kaersutite, rhenite, ilmenite, “orthopyroxene” and “feldspar” glass веlong to late ultramafic paragenesic associated with the process of partial melting. Orthopyroxene in ultramafic rocks is unstable and usually is replaced by minerals of the late paragenesis. Gabbroic xenoliths consist of low-titanium and low-aluminiferous clinopyroxene (#Mg = 0.66-0.56), orthopyroxene (#Mg ≈ 0.5), plagioklase An45-55, often with rims of anorthoclase, titanomagnetite of the same composition as in the ultramafic rocks, ilmenite. Xenoliths have the signs of partial melting and metasomatic transformation preсеding to melting. As a result the orthopyroxene from lherzolite is replaced by clinopyroxene. This leads to the width development of wehrlites and olivine clinopyroxenites. During metasomatosis the content of Mg, Cr and Ni falls while Ti, Fe, Al, Ca grows, as well as the content of large ion lithophile an high-strength elements providing increase of fertility of basalt magmatic source. Composition of the produced melt is close to basanite. The glass, cementing crystallization products, preserved in xenoliths, has a composition close to the orthopyroxene-feldspar mixtures. The mineral phases in such glass presented by clinopyroxene, kaersutite, rhenite, plagioclase, anorthoclase, nepheline, titanomagnetite and ilmenite.
112-125 344
Abstract
The age of ulramafic rocks of the Karabash massif (1720-1740 Ma), the minimum age of their protolith (1830 Ma), and the age of formation of rodingites (438.5 ± 15 Ma) and chlorite-carbonate rocks (404.4 ± 8.8 Ma) were determined on the basis of the SHRIMP analysis of zircons. The rocks were finally transformed 310-315 Ma ago. The ultramafic rocks were the important part over the entire evolution of the massif. The late zircons were formed from the U-rich fluids. Absolutely new variety of zircons, which indicate the participation of another source, was crystallized only in chlorite-carbonate rocks.
126-138 463
Abstract
New data about the stable carbon and oxygen isotopic composition for the Frasnian/Famennian and Devonian/Carboniferous boundary intervals, as well as for middle and upper parts of the Tournasian Stage (the Lower Carboniferous), are represented in this article. Isotopic composition, specific features and depositional conditions which were revealed in the isolated carbonate platform basin are considered.
SHORT COMMUNICATIONS
139-146 389
Abstract
Some new data on the chemical composition and morphology of the pentlandite from meteorites Ural (H5-6), Kunashak (L5-6), Ozernoye (L5), Severny Kolchim (H3), Kargapole (H4), and Chelyabinsk (LL5) are resulted in the paper. We found a natural decrease in the Ni/Fe ratio in pentlandite from ordinary chondrites by the chondrite series H-L-LL and by direction from 3-d to 5-6-th petrological types within these groups. It is shown that the ratio of Cu/Ni pentlandite of the studied H chondrites is different from pentlandite of L and LL chondrites.
ISSN 1681-9004 (Print)
ISSN 2500-302X (Online)
ISSN 2500-302X (Online)