Petro fabric characteristics of olivine from xenoliths, peridotites, and basalts (from Canary Islands, Kuznetsk Alatau and Yoko-Dovyren Massif)

This paper presents results of study of petro fabric specific characteristics of olivine from xenoliths, peridotites, and basalts (from Canary Islands, Kuznetsk Alatau and Yoko-Dovyren Massif

Sedimentary deposits and petrography of the basalts of the island of Tenerife of the Canary archipelago (Spain)

The article is devoted to the study of sedimentary deposits on the slopes of the Teide volcano and petrography of the volcanic rocks of the island of Tenerife of the Canary archipelago (Spain). A description of the sediments, which are presented on the island's territory, and an analysis of the features of the material composition of rocks are given

Features of geology and composition of rocks from the alkaline-gabbroid University massif (NE Kuznetsk Alatau ridge, Siberia)

This paper discusses specifics of petrography and structural tectonic position of the alkaline-gabbroic University massif, which is a sort of analogue of the Kiya-Shaltyr deposit of nepheline ores in this area that was very slightly eroded. In this work, we will also present new precise analytical data on rare and trace element distribution in major intrusive phases of this geological object, and also isotope dating on the basis of Sm-Nd method

The Barkhatny ultramafic-mafic massif (Kuznetsk Alatau Ridge, SW Siberia): structural and compositional evolutions of rocks

A complex of petrographic and petrofabric analyses that was carried out for rocks from an ultramafic-mafic massif of the Barkhatnaya Mountain in the Northern part of the Kuznetsk Alatau allowed us to prove that internal anisotropy of mineral aggregates had deformation-type evolution, which indicates possible plastic exhumation of lithosphere mantle fragments into upper crust levels. Additional mineralogical and geochemical researches of the basic component point out high possibility of multistage model for obduction of ophiolite association segments proposed for this region

Geological structure and prospects of noble metal ore mineralization of the Khayrkhan gabbroid massif (Western Mongolia)

An analysis of the distribution of noble metals in zones of sulfide mineralization makes it possible to justify the isolation of four ore-bearing horizons with a specific geochemical zonation. A rise in the gold content relative to palladium and platinum is observed from the bottom upwards along the section of the stratified series of gabbroids. The study of the mineral phases of sulphides and the noble minerals itself indicates the evolution of hydrothermal solutions, which determines the different activity and mobility of the fluid (mercury, tellurium, sulfur) and ore (copper, nickel, iron, platinum, gold and silver) components

Features of geology and composition of rocks from the alkaline-gabbroic University massif (N-E Kuznetsky Alatau ridge, Siberia)

This paper discusses specifics of petrography and structural tectonic position of the alkaline-gabbroic University massif, which is a sort of analogue of the Kiya-Shaltyr deposit of nepheline ores in this area that was very slightly eroded. In this work, we will also present new precise analytical data on rare and trace element distribution in major intrusive phases of this geological object, and also isotope dating on the basis of method Sm-Nd

Thermodynamic modelling of metamorphic processes: state of the art in pseudosection approach

Understanding global-scale orogenic processes related to supercontinents, and their relationship to the secular evolution of the Earth's lithosphere, represent important challenges for Earth scientists today. The record of these processes is preserved in the microstructures, mineral assemblages and mineral compositions of lithospheric rocks exhumed to the Earth's surface. Given a well-characterized microstructural evolution, thermodynamic modelling is the key to quantifying changes in pressure and temperature, with the rate of these changes being provided by rock-forming and accessory mineral-based geochronology. Thus, metamorphic rocks provide Pressure–Temperature–time–deformation (P–T–t–d) data that help to parameterize orogenic processes

Ore-forming Сonditions of the Blagodat Gold Deposit in the Riphean Metamorphic Rocks of the Yenisey Ridge According to Geochemical and Isotopic Data

Neodymium and strontium isotopic composition and rare earth elements (REE) distribution pattern have been determined in whole rocks and minerals were separated from host metamorphic rocks and disseminated sulfide ores of the Blagodat gold deposit. Isotopic data are given to construct few isochrones that could be reflected an age of main stages of metamorphic and metasomatic alteration in rocks varieties during a successive accumulation of gold in structural traps. The significant temporal range in the forming of the studied rocks can be interpreted as an evidence of multi-stage tectonic destruction accompanying with trust-folding processes, shear deformations and development of local fracture zones that had place from the Late Riphean to Middle Paleozoic time. According to isotopic data basic ore-forming processes were realized in the relatively narrow interval from 690 to 750 Ma that correspond to a beginning of continental rifting on the western margin of Siberian craton. Chemistry and trace element distribution are closed for host and auriferous schists and mainly showed differences in the composition initial sedimentary units. The middle negative value εNd (from -14 to -16) and very high positive value εSr (from +570 to +725) are mostly corresponded to that of upper continental crust matter. The role of synchronic granite intrusions in the studied area can be only estimated due to a generation of thermal energy and crustal fluids