The results of the study of mineral composition and microstructure of representative metapelitic and calcic pelitic schist and amphibole-biotite gneiss, occurring in the northern part of the Western Ny Friesland anticlinorium, are reported. Mineral composition was analyzed with a JSM-6510LA scanning electron microscope with a JED-2200 (JEOL) energy dispersive spectrometer. Metamorphic conditions were assessed with various mineral geothermometers (garnet-biotite, Ti-in-biotite, Ti-in-muscovite, Ti-in-amphibole, garnet-amphibole, amphibole-plagioclase, and chlorite) and geothermobarometers (GASP, GBPQ, GRIPS, GBPQ, phengite, etc.). It has been shown that peak temperature and pressure for rocks of the Paleoproterozoic Atomfjella Series forming the western limb of the anticlinorium are consistent with those for the high-pressure part of the upper amphibolite facies (690-720 °С, 9-12 kbar), and the peak temperature and pressure for rocks of the Mossel Series occurring in the eastern limb and rest on the Atomfjella rock sequence, are consistent with the high-pressure part of the lower amphibolite facies (580-600 °С, 9-11 kbar). In addition to the high-temperature parageneses Ms-Bt-Grt-Pl (±Ky, St), Bt-Grt-Pl-Kfs-Cal (±Scp) and Bt-Hbl-Ep-Grt-Pl, the rocks of the both series display the low-temperature assemblage Ms-Chl-Ep-Ab-Prh-Ttn, which was formed upon transition from greenschist to prehnite-pumpellyite facies (260-370 °С).
The paper discusses some general relations between the structure of metamorphic rocks and mechanisms of phase reactions. Among these relations is the influence of nucleation and growth of kinetics on the crystal size distribution. A brief overview is made of theoretical models which have been proposed to explain granulometric properties of rocks, and kinetic laws and factors on the metamorphic crystallization are considered by the example of metapelitic garnets, including the phenomenon of avalanche nucleation at finite overheating as well as the growth of porphyroblasts under diffusion-limited conditions. As a result, a new approach to modeling of native granulometric curves is presented.
The main objects of the research were the deposits of noble and non-ferrous metals of the Urals, Siberia and Novaya Zemlya. It is shown that the study of the variability of the material composition and stereometric features of ores (with computer modeling of the most important types of mineral aggregates) in the geological space is extremely important to reduce losses of useful components, predict the technological properties of mineral raw materials and identify the conditions of ore formation.
The main objects of the research were the deposits of noble and non-ferrous metals of the Urals, Siberia and Novaya Zemlya. It is shown that the establishment of a pomineral balance of distribution of chemical elements in ores, the study of variability of the material composition and stereometric features of ores in the geological space is extremely important to solve the problems of rational use of ore deposits and the prediction of environmental consequences of their development. When assessing the environmental impact of the deposits involved in the exploration and exploitation, both the regularities of distribution of toxic elements and minerals in the volumes of ore bodies and fields, and landscape-geochemical conditions determining the factors of migration and accumulation of these components after their extraction on the earth surface should be taken into account. For geological-economic and environmental forecasting it is necessary to accumulate materials on the distribution of impurity elements, sometimes not playing a role in assessing the industrial importance of deposits, but leading to the emergence of various man-made geochemical anomalies in areas of exploration and mining operations, as well as the formation of man-made deposits in places of waste storage of concentration plants and metallurgical plants.
The article considers the main directions of research in the analysis of the regularities of the location, properties and state of the main types of deposits of solid minerals in Russia. A summary of the available data on the main patterns of variability of both individual minerals and aggregates in the main types of endogenous ore deposits is made. Mineralogical features of large and unique deposits connected with granite magmatism are analyzed. It is concluded that their formation was determined by the long-term evolution of deep fluid systems serving as a means of mantle-core interaction and redistribution of matter in the Earth's crust. The principles of granite pegmatites analysis and methods of its carrying out are offered. The computational modeling of the processes of structure formation during magma solidification using the Monte Carlo method has been carried out. The possibilities of application of fractal analysis to solve the problems of ore geology are investigated. Possibilities of quantitative assessment of morphology of ore bodies are shown. Methods of studying and modeling of anomalous geochemical fields associated with mineral deposits are outlined. Tasks of geological exploration and prospecting works in connection with the further development of the coal industry are given.
Проанализированы состояние проблемы и подходы к прогнозированию редкометального оруденения, обсуждены принципы и методике прогнозирования, показано, что прогнозирование эндогенных, в том числе редкометальных, месторождений должно базироваться на системном анализе, моделировании в геокибернетическом (количественном) подходе.
За последние годы в олсворудных районах Дальнего Востока выявлен ряд объектов грейзенового типа касситерит-кварцевой формации ...
Минерализованные купола - один из наиболее распространенных морфологических типов грейзенов - представляют интерес не только с практической точки зрения как концентраторы олова, вольфрама, молибдена и других редких металлов, но и в плане изучения вертикальной зональности ...
