The results of geological, geochemical, and geochronological studies of granophyre rocks from the Jarva-Varaka Massif (Kola region) are presented. The 2-km section of the massif is composed of mafic and felsic norites, hypersthene diorite, pigeonite-augitic diorite, quartz diorite, and granodiorite. All these rocks contain a variable amount of granophyre (micropegmatite), from 10

Первая находка псевдотахилитовой брекчии и другие признаки ударного метаморфизма в породах обрамления массива Ярва

Аннотация.Проведено локальное SHRIMP II датирование бадделеита и циркона из пижонитавгитовых диоритов расслоенного массива Ярва-варака, расположенного в Мончегорском районе.Ранее на основе геолого-петрологических исследований была предложена импактная модель происхождения массива.

Аннотация.По результатам геоморфологического анализа района горы Домашняя сделаны выводы о местных тектонических событиях в недалеком прошлом, а также об их возможном повторении в скором будущем.Для проверки этого предположения проведены исследования физических свойств (плотность, упругая анизотропия) образцов горных пород, отобранных с земной поверхности.Результаты измерений подтверждают выводы более ранних работ аналогичного содержания: для поддержания стабильных условий в поле напряжений горного массива необходимо наличие обратной зависимости между

Физические свойства (упругая анизотропия и плотность) образцов горных пород массива Ярва-варака (Мончегорский район)

4. Иванов А.С.Методика статистической обработки составов типоморфных минералов кимберлитовых трубок в Якутии.Прикладная Геохимия.Вып. 5. Москва.2005. 5. Иванов А.С.Методика вычисления минеральных парастерезисов в кимберлитах.Труды XIII Всеросcийской (с международным участием) научной школы «Математические исследования в естественных науках».КНЦ РАН Апатиты,

ПЕТРОФИЗИЧЕСКИЕ СВОЙСТВА ПОРОД И РАСПРЕДЕЛЕНИЕ УРАНА В ЛИЦЕВСКОМ УРАНОВОРУДНОМ РАЙОНЕ КОЛЬСКОГО ПОЛУОСТРОВА

Fluid inclusions in quartz from rocks of different ages and with different uranium contents were studied by microthermometry, gas chromatography, and Raman spectroscopy in three areas with uranium mineralization (Skal'noe, Polyarnoe, and Dikoe) in the Litsa ore district of the Kola Peninsula. The studies have revealed differences in the homogenization temperatures, composition of water-salt systems, and salinity of primary and secondary fluid inclusions in the rocks of these areas. Primary fluid inclusions in the rocks of the Skal'noe and Dikoe areas are characterized by a water-salt system with K and Mg (seldom, Na) chlorides and salinity of 0.2 to 13.9 wt.% NaCl equiv. Secondary inclusions are of higher salinity, up to 19.5 wt.% NaCl equiv., and contain Ca chlorides. Primary inclusions in the rocks of the Polyarnoe area show a more complex salt composition with K, Mg, Ca, and, probably, Li chlorides, with salinity varying from 1.7 to 10.4 wt.% NaCl equiv. Salinity of secondary inclusions is higher, up to 16.9 wt.% NaCl equiv. The gas component of fluid in the rocks of the Skal'noe and Dikoe areas is almost pure CO2 (99.3-100 mol.%); the presence of N-2 (1.1 mol.%) and CH4 (0.4 mol%.) was revealed in few inclusions only. In the Polyarnoe area, only water inclusions with N-2 were found in the rocks. Thus, the fluids in the rocks of the three areas have mostly a CO2-H2O composition with the presence of K, Mg, and Ca chlorides and, seldom, a water-salt composition with the presence of Na salts only. The increased salinity of secondary inclusions and their more complex composition (CO2 with N-2 and CH4 impurities) indicate that the fluid became more reducing and might be responsible for the formation of uranium mineralization. (C) 2017, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.

Zircon crystals from granophyre norites of the Jarva-varaka massif of the Monchegorsk ore region (the Kola Peninsula) have been studied by means of back-scattered electron (BSE) imaging and Raman spectroscopy. The Jarva-varaka massif according to geological and geochemical data has been compared with the Sudbury structure, for which an impact origin is assumed. Zircon study is stipulated by zircon ability to keep signs of shock metamorphism even under granulite-facies conditions, thus it can be used for identification of ancient impact structures. BSE images reveal complicated internal texture – darker central domains (cores) and light rims without texture. Mineral inclusions in zircon are represented by sillimanite and plagioclase which indicates that the studied zircon grains were inherited from the host aluminous gneisses. Zircon crystals show variation of Raman spectra from the core of crystals with typical zircon Raman pattern to complete absence of spectral bands in the marginal parts and rims. Mineral inclusions in zircon rims also have no Raman spectra. Such patterns may be associated with the transformation of crystalline zircon (and mineral inclusions in it) to diaplectic glass under the influence of shock metamorphism, core domains were screened by rims and thus preserved their structure. The received data suggest the participation of the meteorite impact in the formation of the Jarva-varaka massif that requires further investigation.

Anisotropy of elastic properties of core specimens of Cretaceous terrigenous sedimentary rocks, which serve as collectors for the gas condensate field with unique reserves, has been estimated for the first time using the acoustopolarization method. Elastic and density characteristics of rocks are compared with their petrographic description, while the spatial positions of elastic symmetry elements of specimens are compared with their structures. Facts presented in the paper give grounds to hope that scrutinization of the nature of variations in the elastic anisotropy of sedimentary sequences along the vertical and lateral directions can foster works devoted to engineering-geological investigations, as well as forecasting and prospecting for new deposits.

Elastic characteristics of rock samples from the Luchlompolo fault zone taken from outcrop surfaces are compared with elastic characteristics of core samples of the Kola ultradeep borehole taken in an analogous interval. An inversion consisting of a discrepancy between the schistosity levels of rocks in the borehole (below the Luchlompolo fault) and their analogues at the surface (above the fault) is explained by a considerable difference in the force actions that caused the schistosity and layering of rocks in the borehole and at the surface. A kinematic scheme of the fault is constructed, and a hypothesis about the existence of an inversion point (region) in the fault zone and its probable collecting properties is put forward.An inverse dependence of variations in density characteristics of rocks on acoustic dichroism and their elastic anisotropy coefficient for transverse waves is established for the first time.