Part 1 - Lithium

The SIMS method (secondary ions mass-spectrometry) determined the impurity composition of a beryl crystals (aquamarine) from the pegmatites of the Pashki lithium deposit (Nuristan province, Afghanistan). 12 local determinations of the content of 20 chemical elements (including halogens and water) were performed. In comparison with aquamarine from rare metals, including spodumene pegmatites from other regions of the world, the studied beryl is significantly enriched with large ion lithophile elements: Li (about 1100 ppm), Na (4500 ppm) and K (300 ppm). High concentrations of alkaline elements in the beryl of lithium pegmatites are considered as a genetic sign of the high potential of alkalis created during the crystallization of spodumene associated with beryl and other lithium minerals. This well-known genetically determined feature of beryl, characteristic of productive lithium pegmatites, therefore is promising in the development of search and evaluation criteria for lithium pegmatites of Nuristan and other pegmatite provinces.

Pegmatites are crucial sources of rare metals, and their formation is closely related to granites. However, the magmatic evolution process of granite–pegmatite systems, including the changes in environmental characteristics and the rare-metal enrichment mechanism, remains controversial. The Mufushan complex of Southeast China, which formed through multiple episodes of large-scale magmatism, comprises seven lithological units: biotite granite, two-mica granite, muscovite granite, microcline pegmatite, microcline–albite pegmatite, albite pegmatite, and spodumene–albite pegmatite. These units record multistage magmatic evolution and are closely related to rare-metal mineralization. Garnets in these units, primarily occurring as accessory minerals, are magmatic garnets belonging to the almandine–spessartine solid solution series. Chemical analyses of these garnets provide insights into the evolution of the granite–pegmatite system and rare-metal mineralization. Linear trends in the MnO, rare earth element (REE), Y, and Sc contents and the (Gd/Yb)N versus Y/Yb ratios in garnets suggest that the granites and pegmatites of the Mufushan complex originated from the continuous evolution of a homologous magma. Moreover, the variation of garnet δ56Fe values reflects a decreasing-then-increasing trend in oxygen fugacity during the evolution of the granite–pegmatite system. However, the evolution of the granite–pegmatite system was not merely a gradual transformation. An abrupt event occurred in the late stage. Significant H2O enrichment in spodumene–albite pegmatites is evidenced by the garnet H2O, REE, Y, and Sc contents, Y/Ho ratio, and δ56Fe values, marking a shift from the magmatic stage to a magmatic fluid-rich stage. Petrographic evidence further indicates that garnets crystallized earlier than spodumenes, suggesting that the pegmatite melt was already significantly H2O-enriched before spodumene formation began. Additionally, the MnO content in garnets is closely correlated with pegmatite evolution and rare-metal mineralization, making MnO-rich garnets indicators of highly fractionated spodumene pegmatites. Multiple factors contribute to the excellent mineralization potential of the Mufushan complex. Multiple episodes of magmatism facilitate continuous magma evolution and rare-metal enrichment. The initial granitic magma in the Mufushan complex was fertile, with the Lengjiaxi Group providing a substantial source of materials for rare metal mineralization. Moreover, the significant enrichment of H2O before the crystallization of spodumene during the late pegmatite stage played an important role in the formation of spodumene and lithium mineralization.

It is shown that the concept of "rare elements" is rather conditional. The list of rare elements, as well as their selection criteria, constantly changed over time. Geochemical and mineralogical criteria gradually became closely connected with technological and economic criteria. Such criteria as insignificant distribution in the earth's crust, weak mineral formation, and the lack of large deposits were joined by technological difficulties of extraction, minimal use in technology, unprofitable extraction, or artificial shortages due to monopolization of reserves by supplying companies. The list of critical mineral raw materials, which is based on rare chemical elements, is growing every year, with almost all the elements with a clarke of less than 100 ppm being in short supply. This encourages mineralogists to look out for a wider range of carrier minerals of rare elements than it was before, thus expanding the list of rare elements. It is reasonable to group carrier minerals of rare elements not by geochemical, but by chemical properties of the elements, since similar properties are crucial for their use in the same industries. The mineral database of Ukraine includes about 900 mineral species, and in six hundred of them rare elements are species- and speciation-forming. It is suggested to divide them into the following groups: minerals of alkaline (Li, Rb, Cs), alkaline earth (Be, Sr, Ra), transition (Sc, Zr, Hf, V, Nb, Ta, Mo, W, Re, Cd, and Hg), amphoteric (Ga, In, Sn, Tl, Bi), noble (Pt, Ru, Rh, Pd, Os, Ir, Au, Ag), rare earth (Y, La, Ce and other lanthanides) and radioactive (Th, U) metals, semi-metals (B, Ge, As, Sb, Te), non-metals and halides (Se, Br, I). The database should be supplemented with minerals of such low-clarke transition elements as Cu, Co, Cr, Ni, Zn, and Pb, which are predicted to be the elements of the future. Mineral resources of Ukraine contain significant potential for expanding the database of rare element minerals and increasing the reserves of critical raw materials.

We measured noble gases in amorphous silica of geothermal origin. These samples were formed by precipitation from geothermal water in neutral pH, and by the leaching of rocks in acid hot springs. The concentration of 132Xe has a negative correlation with the temperature of geothermal water although 36Ar and 84Kr show no such correlation. The relationship between 132Xe content A (×10−8cm³STP/g) and temperature T(°C) is approximated by the equation A=−(4.5×10−3)T +0.50. The obtained equation should be useful for estimating the silica‐forming temperature that cannot be easily measured by other methods.

Granitic pegmatites are a significant source of critical metals including tin, tantalum, and most notably lithium. To meet future demand, a comprehensive exploration model is required to assist in the discovery of new hard rock deposits. Whereas recent work has largely focused on understanding the source and mineralization processes of pegmatites, the structural controls on the distribution and size of individual deposits remains poorly understood and understudied. In this contribution, we present a structural study on the Zulu pegmatite field in Zimbabwe, which provides a good example of the influence of shear zones, host rock rheology, and lithological competency contrasts on the orientation, size, and distribution of pegmatite bodies within a pegmatite field. At Zulu, we observe both structural and petrographic evidence for two types of pegmatite emplacement within an active shear zone during D2 strike-slip dominated deformation. An early generation (Type 1) was emplaced syn-kinematic to D2 within dilational jogs subparallel to the shear fabric, and continued ductile shearing also drove significant recrystallization which affected the primary magmatic phases and therefore influenced the preserved mineralogy. A later generation (Type 2) was emplaced syn-to-late-kinematic to D2 along tension gashes and subordinate fracture sets oblique to the shear fabric, which served to truncate the cooling history and preserve a primarily magmatic mineralogy within this pegmatite group. By comparing Zulu to other large pegmatite deposits, we conclude that geologic structures are critical to source-to-sink connectivity in lithium pegmatite systems, and affect the mineralization potential of individual deposits by driving recrystallization. Assessing the structural history and relative timing of emplacement within a pegmatite field, in conjunction with detailed (micro)textural observations from within pegmatite bodies, is essential to understanding pegmatite emplacement geometries. A more systematic approach in constraining these relationships will therefore aid in generating new exploration targets in both greenfield and brownfield settings.

В статье приведены опубликованные результаты и новые данные по керну скважин Колмозерского литиевого место рождения (Кольский п-ов, Россия). Колмозерское месторождение — крупное (world-class) по количеству запасов литиевых руд. В России оно наиболее изучено современными геохимическими и минералогическими методами и детально разведано геологическими. Установлены геологические, геохимические и минералогические критерии для поисков литиевых пегматитов на примере Колмозерского месторождения. Месторождение контролируется зоной сдвигового течения (shear zone), расположенной на границе крупных блоков земной коры. Колмозерское месторождение локализовано в архейских мета габбро-анортозитах Патчемварекского массива, входит в состав Колмозерского пегматитового поля и Кольского редкометалльного пегматитового пояса. Редкометалльные пегматиты имеют высокие концентрации SiO2 и Al2 O3 , низкие концентрации TiO2 , СаO и MgO, обеднены Ba, Sr, Y, ∑REE и имеют низкие величины индексов фракционирования — Mg/Li и Zr/Hf, на фоне высоких содержаний Li. Основным источником лития является рудообразующий сподумен. Содержание сподумена составляет 18–20 об.%. Блоковый калиевый полевой шпат и мусковит обогащены Li, Rb и Cs. Отношения элементов в блоковом калиевом шпате — K/Rb, K/Tl, K/Cs, K/Li, K/Ba, K/Sr, Rb/Sr и Rb/Ba могут быть использованы как индикаторы литиевой минерализации. Во вмещающих породах появляются новые минералы — литиевый минерал холмквистит и биотит, обогащенный Li, Cs и Rb. The article presents the published results and new data on the core of the wells of the Kolmozero lithium deposit (Kola Peninsula, Russia). The Kolmozero deposit is a world-class deposit in terms of the amount of lithium ore reserves. In Russia, the Kolmozero deposit is the most studied by modern geochemical and mineralogical methods and has been explored in detail by geological methods. Geo logical, geochemical, and mineralogical criteria for searching for lithium pegmatites are established using the example of the Kolmozero deposit. The deposit is controlled by a shear zone located on the boundary of large blocks of the Earth’s crust. The Kolmozero deposit is localized in the Archean metagabbro-anorthosite of the Patchemvarek massif. Rare-metal pegmatites have high concentrations of SiO2 and Al2 O3 , low concentrations of TiO2 , СаO and MgO, and are depleted in Ba, Sr, Y, ∑REE and have low values of fractionation indices — Mg/Li and Zr/Hf, against the background of high Li contents. The main source of lithium is the rock-forming spodumene. The content of the spodumene is 18–20 vol. %. The megacrystic blocky K-feldspar and muscovite are enriched in Li, Rb and Cs. Indicator ratios in blocky K-feldspar are K/Rb, K/Tl, K/Cs, K/Li, K/Ba, K/Sr, Rb/Sr, and Rb/Ba, can be used as indicators of lithium mineralization. The host rocks contain new minerals, the lithium mineral holmquistite and biotite, enriched in Li, Cs, and Rb.

Granitic rocks in the Nubian Shield rocks of Egypt and elsewhere in the world are major resources of important economic minerals that bear rare metals and/or rare-earth elements. Peraluminous granites and related pegmatites (quartz-rich and excess Al2O3) are potential sources of rare metals. They are developed by re-melting of pre-existing felsic intrusions or metasedimentary rocks. On the other hand, granites and pegmatites that host rare-earth elements are mostly peralkaline (quartz-poor and excess alkalis) that are crystallized within their host igneous rocks during magmatic events. Rare earths are not naturally found as native elements but reside as components within some specific minerals such as bastnaesite, allanite, monazite and xenotime. Tungsten, tantalum-niobium (Ta-Nb) and rare-earth elements (REE) are classified as strategic metals. Strategic metals can be generally defined as metals vital to modern technology and industry, but that have sources susceptible to disruption (UK Science and Technology Committee 2011; Blevin 2012). Generally, the amount and value of production vary markedly in the following order Cr Mn Ti ≫ REE ≫ Ge ≫ Tl. In general, the most common rare metal-bearing minerals in nature are beryl (Be), pollucite (Cs), petallite-spodumene-lepidolite (Li), columbite-tantalite-pyrochlore (Nb-Ta), cassiterite (Sn) and wolframite (W). Sn-W-Ta-Mo-REE mineralizations are associated with a variety of granitic rocks in the Nubian Shield of Egypt. Hussein (1990) groped them as deposits associated with granitic rocks generally of GII and GIII types. Igla is the most prominent example of the tin-tungsten ores near Mersa Alam. Abdalla and El Afandy (2003) believed that the majority of such deposits are hosted by pegmatites that are related to A-type granites, i.e. alkaline magmatism in a within-plate environment in most. This variety of deposits also includes some significant radioactive mineralizations (e.g. Ibrahim et al. 2001; Abdel Warith et al. 2004; and many others).

Students of Igneous phenomena have long since become familiar with the occurrence of rare minerals in pegmatitic bodies. The great local concentration of rare elements in pegmatite minerals provides a remarkably good opportunity for the Investigation of deep‐seated rock constituents, for it is reasonable to suppose that these same elements are widely distributed in minute amounts through the parent rocks to which they are genetically related; but their concentration in pegmatite bodies affords a record of their presence that is lacking in other rocks.The unusual number of rare minerals of the Amelia, Virginia, pegmatites has long attracted attention, and the rare elements of the more abundant minerals which have been investigated in the laboratories of the United States Geological Survey afford an unusual opportunity to study the rare constituents of a pegmatite. This famous locality for rare minerals is situated 38 miles southwest of Richmond, just south of Appomattox River, on the Piedmont plateau.

The role of primary energy and in this context the current and planned role of renewable energy sources in the energy system of Republic of Armenia are presented. The article also discusses the global geothermal energy developments, the current state of exploration of its resources in Armenia and trends in its application. Based on the studies, it can be concluded that Jermahbyur, Karkar, Gridzor, Sisian, Vayots Sar, Aknalich, Armenian NPP and Mukhan are among the most promising geothermal resource sites. However, it is important to note that due to limited exploration, information on geothermal resources in Armenia is not complete and reliable, this range is somewhat conditional, and the real potential of geothermal resources may be much higher. A number of literary sources note that mineral and hot waters of Armenia contain such a quantity of lithium and other rare elements that they can be extracted using the existing and widely used technologies. As follows from some sources, the mineral waters of Hankavan and Azatavan have been studied, in which the quantities of lithium and rare elements up to 15 g / l are found, and these quantities can be extracted from the water using the known technologies. Among these sources are also the outlets of the Dvina, Ptghni and Bjni wells. Meanwhile, such mineral waters with large reserves as Jermuk, Arzni, Dilijan and other water deposits were left beyond these studies. The development of technologies for extracting critical elements from these waters is impossible without a thorough study of their composition. Given the high mineralization of hot springs and mineral waters of Republic of Armenia, it will be beneficial for the republic to conduct research to clarify the composition of geothermal and mineral hot springs. It is proposed to obtain geothermal energy from geothermal and hot mineral waters in combination with the use of technology for extracting lithium and other critical elements.

Mineralogical, geochemical and Sr-Nd isotopes characteristics of fluorite-bearing granites in the Northern Arabian-Nubian Shield, Egypt: Constraints on petrogenesis and evolution of their associated rare metal mineralization

Tin with associated tungsten and rare earth element mineralization at the Zaaiplaats mine is hosted by alkali feldspar granites of the Lebowa Granite Suite which intrude granophyric granites of the Rashoop Granophyre Suite. From the upper contact downward the alkali feldspar granites include a marginal pegmatite (stockscheider), the fine-grained Lease Granite, and the coarse-grained Bobbejaankop Granite. The major mineralization styles consist of subhorizontal, tabular zones (low-grade orebodies) containing disseminated cassiterite in the Lease Granite, a zone of disseminated cassiterite mineralization (ZDM) in the Bobbejaankop Granite approximately 50 m below the Lease Granite, and a series of shallowly plunging and branching pipe orebodies which occur in both granite types and which show a close spatial relationship to zones of disseminated mineralization.The granites contain miarolitic cavities generally less than 5 mm in diameter which range from more than 10 vol percent in the upper facies of the Lease Granite to less than 1 vol percent in the deeper part of the Bobbejaankop Granite. Miarolitic cavities are filled or partially filled by hydrothermal minerals including quartz, albite, chlorite, sericite, fluorite, hematite, and calcite. The zones of disseminated mineralization contain high abundances of miarolitic cavities and appear to reflect zones of hydrothermal fluid accumulation during crystallization. In addition to the small cavities within the disseminated cassiterite mineralization zone, the Bobbejaankop Granite contains a series of large cavities (to approx 1 m) and patches of strongly miarolitic granite. Additional infill phases in mineralized zones include cassiterite, scheelite, synchisite, arsenopyrite, chalcopyrite, galena, and other sulfide phases. Pervasive alteration of the granites is expressed mainly by the replacement of primary biotite by chlorite, sericite, and hematite, by ordering of alkali feldspar (maximum microcline, low albite), and by substantial replacement of alkali feldspar by chlorite, sericite, hematite, and other hydrothermal phases.In the Bobbejaankop Granite below the disseminated cassiterite mineralization zone amounts of Al 2 O 3 , K 2 O, Na 2 O, Ba, Rb, Nb, Ta, and U increase with increasing elevation whereas SiO 2 and Ti decrease. This is compatible with upward crystallization in an evolving F-rich magma, but it may partly reflect upward transport of alkalies and incompatible elements via a fluid phase. The ZDM is a zone of enrichment in SiO 2 , Ba, Cu, Pb, Zn, and Sn, whereas it is depleted in Al 2 O 3 , K 2 O, Na 2 O, Rb, Ta, and U compared to the underlying granite.The increasing importance of sericite as an infilling and replacement mineral as the Alpha pipe is approached suggests that part of the alteration and cavity filling in the Lease Granite occurred at the same time as alteration and mineral precipitation in the Alpha pipe. This increasing importance of sericitic alteration is reflected in the geochemical data by increasing CO 2 , Rb, and Cs contents and decreasing Na 2 O, F, and Ba contents with proximity to the pipe.The distribution of disseminated and pipe-style mineralization at Zaaiplaats reflects a combination of processes including (1) early separation of an H 2 O-NaCl-CO 2 fluid enriched in boron to produce pipelike conduits by collection and upward flow beneath crystallization fronts, supplemented by later dissolution of granite, (2) accumulation of fluorine-rich fluids evolved at a more advanced stage of crystallization beneath downward-advancing crystallization fronts to produce strongly miarolitic zones of the Lease Granite containing disseminated cassiterite (low-grade orebodies), (3) accumulation of fluorine-rich hydrothermal fluids, possibly between upward- and downward-advancing crystallization fronts to produce the disseminated cassiterite mineralization zone, and (4) pervasive alteration of the granites accompanied by filling of miarolitic cavities and pipes. The lack of significant hydraulic or tectonic fracturing during crystallization of the granites at Zaaiplaats was probably the most crucial factor in the development of these unusual styles of mineralization.

The subject of the study are manifestations of carbonatites in the quartz deposit “Vein № 175” - the largest deposit of granular quartz of Ufalei block in the Southern Urals. In the vein № 175 new outcrops of carbonatites are described; thin sections, plates and polished sections from 58 selected samples are made. Mineralogical and petrographic analysis of carbonatites and host rocks was carried out using Axiolab ZS and Olimpus BX 51 polarization microscopes with digital prefixes. The total mineral composition was determined by X-ray diffraction analysis. Fluid inclusions were studied in a Linkam THMSG-600 microcooler using the Olimpus BX 51-52 microscope and the LinkSistem 32 DVNS software. It was established that the deposition of vein quartz preceded to the formation of carbonatites. The quartz vein inherited a tectonic structure which controlled the deposition of carbonate material. The fragments of carbonatite bodies are observed throughout the quartz veins, where they have been preserved. It is established that the carbonatites of the “Vein 175” differ from the carbonatites of the Vishnevogorsk alkaline complex by a low content of rare metal minerals characteristic of carbonatites: pyrochlore, zircon, columbite, eshenite and monazite. It is obvious that the source of rare-metal minerals in the carbonatites of the Vishnevye Mountains, as well as in the magmatic carbonatites of zonal massifs with ultrabasic alkaline complexes, is the substance from which the alkaline rocks were formed. Carbonate rocks of these complexes concentrate rare-metal minerals and have the mantle spectrum of rare and rare-earth elements in their composition. The source of the carbonate material of “Veins № 175” can be sedimentary carbonates lying at the base of the crystalline basement. The absence of rare-metal minerals in the carbonatites confirm this thesis.

The article shows first results of the large pantelleritic dike swarm study. Dike swarm breaks through the Middle Paleozoic granites and has a length of up to 40 km with the general Northeastern extension. The swarm rocks composition corresponds to pantellerite trachytes (AGP ~ 1.1) and pantellerites (AGP ~ 1.3). Felsic feldspars and amphiboles (arfvedsonite and cataphorite) as the main phenocrysts, in the microlite paragenesis, represent the mineral composition and the presence of such rare minerals as lorenzenite, Ca-ancylite, catapleiite, monazite, enigmatite eudialite and titanium is noted, such a set of minerals corresponds to typical agpaitic rocks. The distribution of rare elements in the Tsagaan-Uul dike swarm rocks both in character and concentration level corresponds to the petrotype. The key difference is the presence of Nb–Ta anomaly in pantellerite trachytes and pantellerites, which may indicate the involvement of fluid in the formation of the swarm rocks.

The article presents the impact of contact metamorphism on the ores of the large Novo-Uchaly Cu-Zn massive sulfide deposit (South Urals) as well as structural features of the contact zone and change in mineral composition of the ore and dikes. The study of contact metamorphism is also of practical interest because the ores are enriched in precious metals and rare elements in the local contact areas. The author together with geologists from the Uchaly Mining and Processing Plant carried out a geological and mineralogical mapping of the deposit (underground mine). The analytical studies were based on using optical and scanning electron microscopes. The results of detailed geological mapping are as follows: the thick gabbro-diorite dike is alterated by chloritization, hematitization and silicification, and contains quartz-carbonate-sulfide veinlets. The exocontact zones are usually thin, with thickness less than 10 cm, rarely reach 2 m. The signs of the contact metamorphism of the ores: cataclasis, recrystallization of sulfides; the appearance of the increased amount of rare minerals (magnetite, fahlore, galena); violation of the geochemical zoning caused by local redistribution of chemical elements. These factors characterize the ore transformation by the processes — local contact metamorphism and the subsequent hydrothermal mineralization caused by the remobilization of the ore substance.

The results of geochronological studies on columbite-tantalite and monazite from the rare metal pegmatites of the Kawadgaon–Challanpara area in Bastar craton, central India are presented. Columbite-tantalite yielded U-Pb concordia upper intercept age of 1978±16 Ma (MSWD = 0.18). Radiogenic 207Pb*/206Pb* (T7/6) ages on 4 out of 5 columbite-tantalite vary in a narrow range of 1903 to 2077 Ma and are similar to U-Pb age, whereas, one sample shows younger 207Pb*/206Pb*(T7/6) age of 1728 Ma. Younger Pb-Pb age of 1744 ± 250 Ma (MSWD = 150) has also been indicated by these columbite-tantalite samples. Four out of five monazite samples define Pb-Pb errorchron age of 2050±370 Ma (MSWD = 165) and radiogenic 207Pb*/206Pb* (T7/6) ages on 3 out of 5 monazites show a narrow range of 1983 to 2083 Ma. Other two samples show younger 207Pb*/206Pb*(T7/6) ages as 1254 Ma and 1592Ma. Both monazite and columbite-tantalite indicate disturbance in Pb and U isotopic systematics as revealed by high MSWD. However, selected samples from both monazite and columbite-tantalite indicate age of their formation as c. 2000 Ma. Younger ages, i.e., 1254 to 1744 Ma are indicative of later geological disturbances. Reported age of c. 2000 Ma is comparable to Rb-Sr date of pegmatitic muscovite (1850-2330 Ma) from this area and is younger to intrusive granites of c. 2500 Ma. By analogy, therefore, it may be inferred that the age of the rare element mineralization may be ~2000 Ma old, and linked with younger granitic activity that spanned over the period from 2300 to 2100 Ma in the Bastar craton.