bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silurian Terrigenous-Carbonate Sedimentaion in Gorny Altai: Structure, Facies Variability, Faunal Assemblages, and Stratigraphic Position
Authors: Sennikov N.V. , Khabibulina R.A. , Obut O.T. , Novozhilova N.V. , Tokarev D.A. , Luchinina V.A. 
Published: June 2019

Abstract
—This paper discusses the structure and facies variability of the Silurian mixed terrigenous-carbonate strata and presents new paleontological and biostratigraphic data. It attempts to refine the stratigraphic position and provide new lithologic evidence (markers) for regional manifestations of global sedimentary events (Mulde transgressive-regressive and Linde regressive events) in the Altai sections. The chronostratigraphic position of the Kuimov Horizon, a regional stratigraphic unit, has been defined based on graptolite and conodont faunas.
Mantle–Crustal Nature of Early Paleozoic Alkaline Intrusions in Central Sangilen, Tuva (from Nd, Sr, Pb, C, and O Isotope Data)
Authors: Vrublevskii V.V. , Nikiforov A.V. , Sugorakova A.M. , Kozulina T.V. 
Published: June 2019

Abstract
—The Paleozoic foidolite–foyaite plutons of the Sangilen upland (Bayan-Kol, Dakhu-Nur, Chik, and Kharly ones) might have formed in the Late Cambrian–Early Ordovician (~490–500 Ma, Sm–Nd and U–Pb); they are the result of the oldest alkaline magmatism in southeastern Tuva. The intrusion was accompanied by the formation of high-temperature (up to ~600–900 ºC) endogenous carbonate rocks containing calcite, alkali pyroxene, Na–Ca amphibole, biotite, fluorapatite, microcline, and nepheline. Silicate and carbonate derivates were produced, most likely, from genetically related heterogeneous sources with εNd(T) varying from 3.0 to 6.3 and from –0.5 to 6.5, respectively, which might be due to the mixing of the depleted (PREMA) and enriched (EM) mantle materials. Initial ratios 207Pb/206Pb ≈ 0.89 and 208Pb/206Pb ≈ 2.15 in K-feldspar from calcitic rocks are close to those of EM 1. The correlation between the stable-isotope ratios (δ18O ~ 7.2–19.5, δ13C from –6.0 to –1.4‰) and the high 87Sr/86Sr(T) ratio (0.7057–0.7076) indicates a significant crustal contamination of magma in the upper horizons of the lithosphere and a minor impact of a meteoric fluid. The assumed synchronous formation of the studied plutons and other alkaline rock complexes of the Early Paleozoic Large Igneous Province in the west of the Central Asian Orogenic Belt as well as their isotope similarity do not rule out that the intrusion took place in the plume–lithosphere interaction setting.
Seismic Activity of the Khambinskii Fault (Southwestern Transbaikalia)
Authors: Smekalin O.P. , Chipizubov A.V. , Radziminovich N.A. , Imaev V.S. 
Published: June 2019

Abstract
—The paper presents results of a seismogeological study based on analysis of seismic data and historical facts about the seismic activity of the Khambinskii fault zone. According to the data obtained, a genetic type of dislocations on conjugate faults (Gusinoe Ozero and Orongoi paleoseismogenic structures) is related to reverse faults with a strike-slip component. Geophysical studies of the Gusinoe Ozero structure have determined the dip of the fault plane toward the mountain framing of the depression and its outcrop at the bottom of the seismic scarp. The significant seismic potential of the Khambinskii fault is responsible for the maximum intensity of shocks in the nearby cities and settlements of southeastern Transbaikalia. The seismic fault activity has been confirmed by the historical earthquakes of 1856 and 1885, the M = 5 earthquake that occurred on 2 October 1980, and at least two prehistoric earthquakes. The latest of the latter occurred no earlier than ~4 ka and had M = 7.0–7.3, while the earliest was even more intense and took place in the first half of the Holocene, no later than ~6 ka.
Composition and Genesis of Accessory Mineralization in Manganese Silicate Rocks of the Triassic Sikhote-Alin Chert Formation
Authors: Kazachenko V.T. , Perevoznikova E.V. 
Published: June 2019

Abstract
—Manganese silicate rocks together with silicate–magnetite ores and jaspers (Late Anisian–Ladinian) form lenticular or tabular bodies in the Triassic Sikhote-Alin chert formation. The lower part of the formation (Olenekian–Early Anisian) is enriched in clayey and organic matter. Nickel and cobalt compounds and other ore minerals in the Sikhote-Alin manganese silicate rocks belong to two genetic groups including minerals of the valence and ultimately reduced Ni, Co, and other metals. Minerals of the valence species of Ni, Co (sulfoantimonides, sulfoarsenides, sulfides, antimonides, arsenides, tellurides, and silicates), and other metals (galena, sphalerite, chalcopyrite, arsenopyrite, wolframite, scheelite, molybdenite, cassiterite, stannite, cinnabar, stibnite, boulangerite, jamesonite, bournonite, löllengite, bismuthite, fahlore, altaite, native Sb and Bi, etc.) formed from the protolith material during metamorphism under the same conditions as the rock-forming minerals. The presence of minerals of ultimately reduced Ni, Co (maucherite, native Ni, Ni phosphide, Ni and Co chromides, disordered solid solutions, and intermetallic compounds of Ni with Cu, Zn, Sn, and Pb), and other metals (native Pb, Zn, Fe, Sn, Se, Au, Pt, “cupriferous gold”, and intermetallic compounds of Cu, Sn, Pb, Sb, Al, and Zn) in the manganese silicate rocks is due to the influence of the organic matter of the underlying carbonaceous silicites. During metamorphism, the most volatile components (first of all, poorly bound water and hydrocarbons) were released from the heated carbonaceous rocks; as a result, a metal-enriched fluid with highly or ultrahighly reducing properties appeared, which migrated along fractures into other rocks. The manganese silicate rocks are the products of contact metamorphism of siliceous rhodochrosite rocks formed through the diagenesis of biogenic siliceous muds enriched in Mn oxides and organic matter. Erosion of the weathering crust of islands composed of gabbroids of the Kalinovka, Vladimiro-Aleksandrovskoe, and Sergeevka complexes (in the late Middle Triassic–Late Triassic) played the leading role in the formation of metalliferous sediments. Manganese silicate rocks localized in the stratigraphic column above the carbonaceous silicites of the Triassic chert formation are enriched in Au (up to 35.38 ppm), Pt (11.27 ppm), and Pd (5.33 ppm). They contain noble-metal minerals and a wide spectrum of native elements and intermetallic compounds. The presence of Au–Pd–Pt–Ni–Co association (typomorphic for basic and ultrabasic rocks) in the Triassic protoliths of the manganese silicate rocks and carbonaceous silicites is probably due to the sorption of these elements by Mn and Fe hydroxides and organic matter during the exogenous weathering of the ancient Sikhote-Alin gabbroids.
Lateral Zoning of Groundwater Chemistry and Authigenic Mineralogy in the Oxfordian Regional Reservoir of the Nadym–Taz Interfluve
Authors: Novikov D.A. , Vakulenko L.G. , Yan P.A. 
Published: June 2019

Abstract
—This is a pioneering study on lateral zoning of groundwater chemistry and authigenic mineralogy in the Oxfordian regional reservoir of the Nadym–Taz interfluve. According to thermodynamic calculations, the nonequilibrium–equilibrium water–rock system lacks equilibrium with primary magmatic minerals, such as albite, anorthite, and microcline, though the water is moderately saline (up to 63.3 g/L) and has been in interaction with rocks for ~165 million years. Authigenic minerals form continuously and successively (kaolinite–montmorillonite–illite–micas–chlorite–albite–microcline) from waters that have certain рH and contents of SiO2, Al, Na, K, Ca, and Mg. The equilibrium of groundwater with primary aluminosilicate minerals impinges on a carbonate barrier, and almost all rocks are more or less strongly carbonatized. Authigenic mineral assemblages from the southern Nadym–Taz interfluve include kaolinite unlike those from the northern part of the region, where albitization is more common. Authigenesis generally decays in the eastern direction.
Zirconology of the Lherzolite Block of the Nurali Massif (South Urals)
Authors: Krasnobaev A.A. , Rusin A.I. , Valizer P.M. , Likhanov I.I. 
Published: June 2019

Abstract
—Data on the mineralogy, geochemistry, and geochronology of zircons from plagioclase and spinel lherzolite and dunites of the Nurali massif are presented. The age of the main-type zircons from lherzolites (plagioclase ones, 446.2 ± 2.8 Ma, and spinel ones 433.3 ± 3.4 Ma) and dunites (443.8 ± 6.9 Ma) suggests their synchronous crystallization (Tav = 440 ± 5 Ma). The metamorphic age of zircons is 410–415 Ma. In addition to grains belonging to the main subset, the older grains with an age between 527 and 2045 Ma and newly formed metasomatic grains with an age of 380–385 Ma were found. The structure and REE patterns of most zircons from ultramafic rocks point to their magmatic origin, which is probably related to crystallization of a fluidized mantle melt.
Geochemistry of Soda Waters of the Chulym–Yenisei Artesian Basin (West Siberia)
Authors: Lepokurova O.E. , Shvartsev S.L. 
Published: June 2019

Abstract
—Results of studies of soda waters of the Chulym–Yenisei artesian basin are presented. It is shown that these waters are ubiquitous within Cretaceous or Jurassic sediments at depths of ~100–300 m to 1.5–2.3 km. According to the formation conditions, mineralization, and pH, they are divided into three groups: Type I waters spread to a depth of 600 m and have pH = 7.4–8.4 and TDS ≤ 0.5 g/L, type II waters occur at depths of 0.6–2.3 km and are characterized by pH = 8.0–8.9 and TDS = 0.7–4.1 g/L, and type III waters (“Omega”) form a local segment among type II waters and have a unique composition: high alkalinity (pH = 9.0–10.3) and low mineralization (TDS = 0.2–0.6 g/L). We focus special attention on type III waters and present results of studies of their microcomponent, gas, and isotope compositions. The cause of their low salinity and high pH is explained for the first time. Taking into account the isotope data (δD, δ18O, and δ13C), we have established the infiltration origin of soda waters of the three types and the biogenic source of their carbon dioxide. Calculations of equilibria in the water–host-mineral system have shown that all soda waters are in disequilibrium with many primary aluminosilicate minerals but are in equilibrium with a wide range of carbonates and clays. In passing from type I to type III waters, the number of minerals in equilibrium with water continuously increases (albite, microcline, muscovite, and biotite). Taking into account the data obtained, we present schemes of formation of different types of soda waters in the studied basin at different stages of the evolution of the water–rock– gas–organic-matter system and estimate the time of each stage.
The Late Cretaceous East Sikhote-Alin Volcanic Belt: Transition from Subduction to Sliding of Lithospheric Plates (Structure-Geological, Petrological, and Isotope-Geochemical Aspects)
Authors: Martynov A.Yu. , Golozubov V.V. , Martynov Yu.A. , Kasatkin S.A. 
Published: June 2019

Abstract
—The East Sikhote-Alin volcanic belt extending for ~1500 km is commonly considered a single tectonomagmatic structure formed during the Late Cretaceous subduction and the Cenozoic oceanic-slab breakup and active asthenospheric diapirism under transform plate sliding. Based on analysis of the published geological information and the new data on the age and trace-element and isotope compositions of the igneous rocks of the Late Cretaceous Bol’ba Formation, it is shown that the initial stages of volcanism in the southern and northern Sikhote-Alin took place in different geodynamic settings. In contrast to the coeval suprasubductional volcanics of the southern sector (Primorye), the volcanic section of the Bol’ba Formation is dominated by magnesian (Mg# = 26–40) adakites (La/Yb = 19–34) and high-Nb basalts. This igneous rock association and the lead (Δ8/4Рb = 30–46) and neodymium (0.51279–0.51281) isotope ratios of the studied rocks suggest the influence of the “hot” oceanic asthenosphere on magma genesis. The earlier slab breakup north of 48–49 °N was due to the oblique convergence of oceanic and continental lithospheric plates in the Late Cretaceous, accompanied by sinistral shears. The results obtained indicate that the lateral zonation of the eastern Sikhote-Alin is due to different geodynamic settings of formation of its northern and southern sectors rather than variations in its basement composition. In theoretical aspect, the performed research is important for the correct reconstruction of the geologic events in zones of convergence of oceanic and continental plates. It is necessary to take into account not only the general direction of the convergence but also the configuration of the plate boundary.
Early Paleozoic Granitoid Magmatism in the East Tannu-Ola Sector of the Tuvinian Magmatic Belt: Geodynamic Setting, Age, and Metallogeny
Authors: Vetrov E.V. , Chernykh A.I. , Babin G.A. 
Published: June 2019

Abstract
—The East Tannu-Ola sector of the Tuvinian magmatic belt is composed of Early Cambrian volcanosedimentary rocks of an island-arc association (Kadvoi, Serlig, and Irbitei Formations), which are intruded by granitoid massifs of different ages (from Cambrian to Devonian) of the Tannu-Ola areal pluton. We analyzed the structural and geologic position, chemical composition, metallogenic signatures, and geochronological (U/Pb) and isotope-geochemical (Sm/Nd and Rb/Sr) characteristics of Early Paleozoic granitoids of the Ungesh pluton (western part of the Tannu-Ola areal pluton). The available and our new data made it possible to establish the specific chemical parameters, age sequence, duration, intensity, and metallogeny of granitoid magmatism in the East Tannu-Ola sector of the Tuvinian magmatic belt. An early Cambrian (534–518 Ma) gabbro–plagiogranite complex similar to the Maina complex in West Sayan has been recognized in the Ungesh pluton. The age and metallogeny of the middle–late Cambrian (508–492 Ma) Tannu-Ola diorite–granodiorite–plagiogranite and Late Ordovician (451–447 Ma) Argolik granite–leucogranite complexes have been refined. Granitoids of the early Cambrian complex formed probably at the initial stage of formation of an island arc, in association with the Kadvoi–Serlig basalt–andesite–rhyolite complex. It is in these granitoids that early low-productivity gold–sulfide–quartz veins and veinlets originated. Granitoids of the Tannu-Ola complex formed at the initial stage of evolution of the accretion–collision system. Magnetite-containing skarns and numerous vein–veinlet zones of late high-productivity gold-sulfide-quartz mineralization evolved in these granitoids. Granitoid massifs of the Argolik complex formed at the final stage of evolution of the accretion–collision system and probably played a crucial role in the regeneration of ore mineralization in some areas.
Tectonophysical Paleostress Reconstructions: Interpretation Challenges and Possible Solutions
Authors: Rebetsky Yu.L. , Marinin A.V. , Sim L.A. 
Published: June 2019

Abstract
—Paleostress inversion may be ambiguous when several markedly different local stress states are inferred for a group of outcrops. Attempts of reconstructing regional stress regimes (compressional, extensional, or strike-slip) by selecting local principal stresses of proximal directions turn out to have poor grounds. Each stress permutation (e.g., extension to compression) attendant with buildup of large irreversible strain (fault slip) requires a 5–6 kbar change in middle-crust horizontal stress and at least 50 Myr stable and uniform loading. Tectonophysical stress reconstructions for present active intracontinental orogens show heterogeneous patterns: Stress directions in uplifts are different from those in large intermontane basins and even in relatively subsided parts of mountain ranges or in adjacent uplifted zones (e.g., a plateau and a range). Paleostresses should be interpreted with reference to present stress fields in the respective areas. It is suggested to reconstruct regional stresses using the approach of L. Sim implying search for “common stress fields”. Another important technique is to trace stress changes in specific structures (large folds etc.) in the course of their evolution. The available data indicate correlation and bipolarity of stress states in large basins and uplifts.
Behavior of Noble Metals during Fractional Crystallization of Cu–Fe–Ni–(Pt, Pd, Rh, Ir, Ru, Ag, Au, Te) Sulfide Melts
Authors: Sinyakova E.F. , Kosyakov V.I. , Borisenko A.S. , Karmanov N.S. 
Published: June 2019

Abstract
—The method of quasi-equilibrium directional crystallization was used for experimental modeling of the behavior of noble metals in the presence of Te during the fractional crystallization of Cu- and Ni-rich sulfide magma. The experimental melt contained (mol.%): Fe = 18.5, Ni = 19.1, Cu = 16.7, S = 44.1, and Pt = Pd = Rh = Ir = Ru = Ag = Au = Te = 0.2, i.e., is similar in composition to the massive pentlandite-bornite ores of platinum-copper-nickel deposits of the Noril’sk group. The crystallized sample consists of six primary zones differing in chemical and phase compositions. The main minerals crystallizing from the melt include the following sulfide phases: bornite solid solution (bnss), quaternary solid solution (tss), described earlier in the literature, and three phases (сfpn, cnpn, npn), which we attributed to pentlandite according to their chemical composition. The primary phases crystallized from the melt decay on cooling with the formation of secondary phases. The сfpn, cnpn, and tss phases decay completely, and the npn and bnss phases, partly. As a result, secondary zoning forms in the sample. Formation of drop-like inclusions of telluride melt was observed in the end zone of the ingot. The obtained data show that pentlandites and tss are the main high-temperature concentrators of PGE, with each of the macrophases showing specific PGE accumulation. Eight types of impurity phases have been detected. They form by different mechanisms: crystallization from sulfide melt of refractory compounds, deposition from telluride melt, and formation through complete or partial decay of primary macro- and microphases. A scheme of the zonal structure of the crystallized sample and the evolution of the phase composition during fractional crystallization has been constructed. It clearly demonstrates the intricate formation of primary and secondary major-component and impurity zonings and can be used to explain the nature of the zoned structure of massive PGE-bearing pentlandite–bornite orebodies.
New Data on Granitoids of the Kara Gold Ore Cluster (Eastern Transbaikalia): Age, Genesis, and Sources of Material
Authors: Efremov S.V. , Spiridonov A.M. , Travin A.V. 
Published: June 2019

Abstract
—Study of granitoids spatially and genetically associated with gold mineralization within the Kara gold ore cluster has provided a new insight into their genesis, association with ore mineralization, and the sources of their ore material. The regional granitoids associated with gold mineralization are part of two individual complexes. One of them, earlier assigned to the Amanan complex, has an isotopic age of 182.9 ± 2.6 Ma and must be related to the subduction zone that existed on the southern margin of the Siberian continent in that period. Its granitoids differ in age and composition from the granitoids of the Amanan complex and must be separated as an independent taxonomic unit after an additional geological study. The second, Amudzhikan–Sretensk, complex has an isotopic age of 151.7 ± 1.9 Ma and might be related to the collision of the Siberian and Mongol–Chinese continents after the closure of the Mongol–Okhotsk ocean. In geochemistry the granitoids of the Amanan(?) complex correspond to adakites and must be considered melting products of the basaltic layer of the oceanic lithosphere. The granitoids of the Amudzhikan-Sretensk complex are similar in geochemistry to sanukitoids, melting products of subcontinental sources contaminated with continental-crust material. The granitoids of both complexes have high contents of gold and must be considered gold-bearing. In the Amanan(?) complex, adakites are the gold-richest rocks (as estimated from the slab melt composition), which indicates the primary nature of this gold. In the Amudzhikan–Sretensk complex, the highest contents of gold are specific to primitive sanukitoids, melting products of a mantle source with gold signatures. This suggests the primary nature of gold, whose content is determined by the portion of slab melt in the source of the rock material. The presence of adakites and primitive sanukitoids in the regional granitoid complexes indicates the existence of a subcontinental mantle source with gold signatures during the magma generation. The source formed in the subduction zone that existed on the southern margin of the Siberian continent in the Early Jurassic and was remobilized under collision of the Siberian and Mongol–Chinese continents in the Late Jurassic. This source might have controlled both granitoid magmatism and ore mineralization.
Tectonic Evolution of Late Mesozoic–Cenozoic Basins in Eastern China and Implications for Pacific Plate Subduction
Authors: Wang Hongliang , Liang Jintong 
Published: June 2019

Abstract
—During the late Mesozoic and Cenozoic, the North China Craton witnessed a series of tectonic transition and deformation events, caused mainly by the subducting Pacific Plate and forming many petroliferous basins in eastern China and adjacent areas. Based on analysis related to the reconstruction of balanced sections, the comparison of subsidence rates, and the migration of depocenters in these basins, the tectonic evolution of these basins and their relationships with each other are clearly revealed. The evolution of the Bohai Bay Basin shows a migration from southwest to northeast. The North Yellow Sea Basin’s evolution developed northward, while the South Yellow Sea Basin evolution migrated southwards. The evolution of the East China Sea Basin was activated from northwest to southeast. In combination with the subduction of the Pacific Plate, the conclusions of this study can be summarized in three aspects: (1) The structural pattern of the basin group is characterized by east–west trending belts and north–south trending blocks, (2) tectonic activities in the late Mesozoic–Cenozoic basins evolved from west to east in response to the westward subduction of the Pacific Plate, and (3) due to the collision of the Eurasian Plate and Indian Plate and the transitional pattern of the Tan-Lu Fault Zone from sinistral to dextral, the tectonic evolution of the basin group was centered in the Yellow Sea Basin with the Bohai Bay Basin, evolution migrating northward and the ECSB migrating southward.