Ophiolitic association of Cape Fiolent area,southwestern Crimea

An ophiolitic association consisting of serpentinized ultramafic rocks and serpentinite, layered mafic–ultramafic complex, gabbro and gabbrodolerite, fragments of parallel dike complex, pillow lava, black bedded chert, and jasper has been identified for the first time by authors in the Cape Fiolent area. The chemistry of pillow lavas and dolerites, including REE patterns and a wide set of other microelements, indicates suprasubduction nature of the ophiolites and their belonging to a backarc basin that has reached the stage of spreading in its evolution.     

Gas mixing with aqueous solution in the ore-forming hydrothermal process: an example of gold

The mixing of gas and aqueous fluid in hydrothermal ore-forming processes is discussed with reference to gold deposits to demonstrate that this phenomenon may affect ore deposition. Data on fluid inclusions in samples from the Sukhoi Log and Olimpiadinskoe deposits in Russia are utilized to demonstrate possible implications of gas mixing with hydrothermal solution when gold ores are formed. A simplified thermodynamic model is suggested to show how interaction between aqueous saline solutions with pure carbon dioxide or carbon dioxide—methane mixture may affect gold solubility. Further studying such processes may provide interesting information for understanding the genesis of ore mineralization.     

Molar tooth structures and origin of peloids in proterozoic carbonate platforms (Middle Riphean of the Turukhansk Uplift,Siberia)

Structures and textures of the peloidal wackestones, as well as size, shape, and composition of peloidal grains, from the Mesoproterozoic (Middle Riphean) Sukhaya Tunguska carbonate platform in the Turukhansk Uplift (Siberia) are considered. It is shown that these grains formed in the course of diagenesis were closely associated with the microsparitic replacement and the formation of molar tooth (MT) structures. Diagenetic transformations of rocks were related to the activity of anaerobic microbial communities inside the buried carbonate silt layers. The microbial activity during diagenesis was governed by the carbonate sediment composition and conservation mechanism of the high-molecular organic matter of primary producers therein, since this organic matter was the nutritious substrate for the primary anaerobe communities.     

Stratigraphy and correlation of Mesoproterozoic rocks associated with Mohar cauldron,Shivpuri district,Madhya Pradesh

A circular structure, termed as cauldron of volcanic origin, was located near Mohar village in Shivpuri district (M.P.) in the year 2000. Subsequently, the same structure was called as Dhala structure of impact origin. There may be debate over the origin and evolution of this circular structure, but it is characterized by a unique lithological set-up within the Bundelkhand craton. The circular structure is defined by annular disposition of igneous and sedimentary rocks. This includes a set of felsic volcanic rocks and associated breccias named as Mohar Formation, exposed in the outer rim of the circular structure. The inner part of the circular structure has sedimentary sequence, termed as Dhala Formation.The field relations indicate that the Mohar and Dhala foarmations are younger than Bundelkhand granitoid complex but older than Kaimur Group. This period in Indian stratigraphy corresponds to Semri Group which consists of Porcellanite Formation, the rocks of which have formed due to deposition of volcanic ash.The geochronological data and field relations between different litho-units indicate that the Mohar volcanism which generated large volume of volcanic ash was a possible source for the formation of Porcellanite Formation. The deposition of sedimentary sequence in main Vindhyan basin was continued, whereas the volcanic activity in Mohar area continued till H ≈ 1.0 Ga. Since, acid volcanic activity has been reported in different parts of the world at H ≈ 1.0 Ga., it is possible that the Mohar acid volcanic activity is not an isolated event; instead it may be a part of global volcanic activities around H ≈ 1.0 Ga.     

Dump slope stability analysis – A case study

In opencast mining operation, the stability of waste materials stands at high priority from the safety and economic perspective. Poor management of overburden (OB) dump results the instability of slope in an opencast mine. The present paper deals with the stability analysis of dump material of an opencast coal mine at Talcher coal field, Angul district, Odisha, by means of different geotechnical parameters and mineralogical composition affecting the dump slope. The prolonged rainfall in the mining area causes dump failure and loss of valuable life and property. A recent dump failure that occurred in 2013 at Basundhara mines of Mahanadi Coalfields Limited (MCL), Odisha, took 14 lives, and created problems for the mining industry. Most of the dump failure that occurs in the study area are mainly due to increase in pore water pressure as a result of rainfall infiltration. The stability of the waste dump was investigated using the limit equilibrium analysis to suggest an economical, sustainable and safe disposal of the dump in the study area.     

Nuclear fuel cycle and its impact on the environment

In this paper, we consider the present-day situation and outlooks of the development of nuclear power generation in Russia and other countries. It was noted that the implementation of the concept of a closed nuclear-fuel cycle accepted in Russia relies on the solution of the problem of the disposal of spent nuclear fuel (SNF) and radioactive waste (RAW). This paper presents the main results of investigations focused on the development of radiation-safe methods of manufacturing nuclear fuel elements, including mixed uranium–plutonium oxide fuel for fast-neutron reactors; creation of low waste-production technologies of SNF processing and RAW disposal; and the analysis of fundamental features of the behavior and speciation of radionuclides in environmental objects for the development of efficient methods of radioecological monitoring and remediation of radionuclide-contaminated areas.     

The evolution of slump-induced destruction of Kukuy Griva slope (Lake Baikal) revealed on the base of the data of seismic and acoustic surveys

As a result of careful interpretation of the data of recent seismo-acoustic surveys, two major seismic complexes were identified in the structure of the upper sedimentary section of the north-western slope of Kukuy Griva (ridge). They are composed of several inner seismo-facies, which are very characteristic and separated with well-expressed regional reflector. Seismic and acoustic data revealed evidences of numerous landslide processes which were different in age and peculiarities of manifestation. For the first time, detailed schemes of seismo-facies distribution are compiled for major seismic complexes at the area. The boundary between seismic complexes is dated as 150 thousands years. It is shown that sliding was more intensive during Late Pleistocene and Holocene, reflecting activation of tectonic movements in this part of Baikal rift system.     

The subsidence and thermal history of the Baikit anteclise sedimentary basin

The Riphean rocks of the Baikit anteclise have been examined using pyrolysis Rock–Eval 6 to evaluate the subsidence history and erosion level. The studied Riphean rocks have the МK₃–МK₄ catagenesis grade. Based on the catagenesis of organic matter we propose a model of maximum burial before the beginning of the accumulation of Vendian deposits. Estimated calculations of subsidence and erosion have shown that the assessed catagenesis grade could be reached at a depth of 7 km, while the erosion level was approximately 5–7 km.     

New insight into the composition and the structure of the deep layers of the terrestrial planets

New approaches, which expand the ideas about the compositions and structures of the mantle of the Earth and terrestrial planets, are considered. New data indicate a more fractional structure of the deep layers of the Earth and the Moon. The experimental results at high pressures and temperatures allow modeling the change in the structure and properties of the most important components of the composition of the mantle and cores of the Earth and Moon, as well as the gas (Jupiter and Saturn) and ice (Uranus and Neptune) giants.     

Mineralogy and geochemistry of granitoids from Kinnaur region,Himachal Higher Himalaya,India: Implication on the nature of felsic magmatism in the collision tectonics

Felsic magmatism in the southern part of Himachal Higher Himalaya is constituted by Neoproterozoic granite gneiss (GGn), Early Palaeozoic granitoids (EPG) and Tertiary tourmaline-bearing leucogranite (TLg). Magnetic susceptibility values (<3 ×10^?3 SI), molar Al₂ O ₃/(CaO + Na₂ O + K ₂O) (≥1.1), mineral assemblage (bt–ms–pl–kf–qtz ± tur ± ap), and the presence of normative corundum relate these granitoids to peraluminous S-type, ilmenite series (reduced type) granites formed in a syncollisional tectonic setting. Plagioclase from GGn (An₁₀–An₃₁) and EPG (An₁₅–An₃₃) represents oligoclase to andesine and TLg (An₂–An₁₅) represents albite to oligoclase, whereas compositional ranges of K-feldspar are more-or-less similar (Or₈₈ to Or₉₅ in GGn, Or₈₆ to Or₉₇ in EPG and Or₈₇ to Or₉₄ in TLg). Biotites in GGn (Mg/Mg + Fe^t= 0.34–0.45), EPG (Mg/Mg + Fe^t= 0.27–0.47), and TLg (Mg/Mg + Fe^t= 0.25–0.30) are ferribiotites enriched in siderophyllite, which stabilised between FMQ and HM buffers and are characterised by dominant 3Fe\(\rightleftharpoons \)2Al, 3Mg\(\rightleftharpoons \)2Al substitutions typical of peraluminous (S-type), reducing felsic melts. Muscovite in GGn (Mg/Mg + Fe^t=0.58–0.66), EPG (Mg/Mg + Fe^t=0.31?0.59), and TLg (Mg/Mg + Fe^t=0.29–0.42) represent celadonite and paragonite solid solutions, and the tourmaline from EPG and TLg belongs to the schorl-elbaite series, which are characteristics of peraluminous, Li-poor, biotite-tourmaline granites. Geochemical features reveal that the GGn and EPG precursor melts were most likely derived from melting of biotite-rich metapelite and metagraywacke sources, whereas TLg melt appears to have formed from biotite-muscovite rich metapelite and metagraywacke sources. Major and trace elements modelling suggest that the GGn, EPG and TLg parental melts have experienced low degrees (～13, ～17 and ～13%, respectively) of kf–pl–bt fractionation, respectively, subsequent to partial melting. The GGn and EPG melts are the results of a pre-Himalayan, syn-collisional Pan-African felsic magmatic event, whereas the TLg is a magmatic product of Himalayan collision tectonics.