In this paper we present textural and compositional data for columbite group minerals (CGM) and associated Nb-Ta-Sn oxides from lithium-beryllium-tantalum pegmatite deposits of the Kolmozero-Voronja belt, NW Russia, with the aim of deciphering the above mentioned features for minerals from deposits with different mineral signatures and lithium ore grade. Minerals from four deposits, including two of world-class (Kolmozero and Polmostundra), are examined. It is shown that the main controlling factors are the diversity and rate of magmatic fractionation, hydrothermal overprint and mineral paragenesis followed from the specific geochemical signature of the different pegmatite deposits. CGM from Kolmozero include several mineral species (columbite-(Fe), columbite-(Mn), tantalite-(Fe), tantalite-(Mn)) showing large compositional variations, mainly controlled by Nb-Ta fractionation (Ta/(Ta+Nb) = 0.16-0.70; Mn/(Mn + Fe) = 0.45-0.63). Textural patterns are extremely various (oscillatory, homogeneous, patchy, spongy, somewhere with over-growing Ta-rich rims) and indicate the involvement of numerous magmatic and hydrothermal processes. The Polmostundra CGM are represented by columbite-(Fe) with Ta/(Ta+Nb) ranging from 0.05 to 0.39 with homogeneous, mottled, oscillatory, patchy and irregular reverse textures. The Okhmylk CGM are irregular normal, patchy and homogeneous columbite-(Fe) and columbite-(Mn) with Ta/(Ta+Nb) = 0.09-0.24 and Mn/(Mn + Fe) = 0.29-0.92, indicating the suppressed magmatic fractionation and iron drop due to precipitation of Fe minerals. Columbite-(Fe) and columbite-(Mn) from the Be-Ta Shongui deposit are less evolved with Ta/(Ta+Nb) = 0.07-0.23 and Mn/(Mn + Fe) = 0.31-0.55. The minerals are characterized by progressive normal, oscillatory, homogeneous and ir-regular reverse patterns. Associated pyrochlore minerals occur both as early magmatic (Kolmozero) and late hydrothermal (Polmostundra, Okhmylk). Cassiterite is found only in the Okhmylk dykes and is apparently of hydrothermal origin. CGM from Li pegmatites have impurities of Ti (0.01-0.05 apfu) and W (up to 0.02 apfu), whereas CGM from Be pegmatites contains elevated Ti (up to 0.09 apfu). The mineral systems analysis presented here is relevant for exploration.

The Sidi Bou Othmane (SBO) pegmatite district is in the Central Jebilet massif, Occidental Meseta domain, Morocco. The SBO district is hosted essentially in a volcano-sedimentary series composed of the Late-Devonian Sarhlef shales. Pegmatite bodies crop out as dykes, which are oriented from N-S to E-W and are generally variably deformed with ductile and/or brittle structures with ante, syn- or post kinematic criteria. Petrographic observations of pegmatite dykes show that feldspars (i.e., albite, microcline) are the most abundant mineral phases, followed by quartz, micas, with tourmaline and accessory mineral as garnet, and zircon and secondary minerals as clinochlore, sericite, and illite. The geochemical study indicates that, according to the major pegmatite elements dykes of SBO have mainly a S-type granitic composition and are peraluminous granite with calc-alkalic affinity. The study of trace elements pointed out that SBO pegmatite formed under post-orogenic syn-collision context during the Variscan orogeny, by the partial melting of argilliferous sediment and can be ascribed to the muscovite-bearing pegmatite; moreover, they have a good potential on ceramic and contain minerals, such as feldspar, recently assessed as Critical raw materials by European Union.

The Huayangchuan uranium deposit, located in the west of the Xiaoqinling belt on the southern margin of the North China Craton, is a polymetallic deposit dominated by U, Nb, Pb, and rare earth elements. The Huayangchuan uranium deposit, discovered in the 1950s, has long been known as a carbonatite-type uranium deposit. Recently, new geological work has found uranium mineralisation in many granitic pegmatite veins in the Huayangchuan deposit and adjacent areas. Here, we report a systematic investigation of the petrography, whole-rock geochemistry, zircon U-Pb ages, and in situ Lu-Hf isotopic characteristics of newly discovered U-rich granitic pegmatite veins in the west of Huayangchuan deposit. The petrological results showed that the lithology of the samples is equivalent to that of granite. The U-Pb ages of zircon were 1826.3 ± 7.9 and 1829 ± 11 Ma. Microscopically, the symbiotic characteristics of zircon, betafite, and uraninite exist in the intergranular fissures of K-feldspar and quartz, reflecting metallogenic phenomena in the rock formation process. Almost all whole-rock samples were rich in SiO2 (64.37–70.69 wt.%), total alkalis (K2O+Na2O = 8.50–10.30 wt.%), and Al2O3 (12.20–14.41 wt.%), but poor in Ti2O (0.23–0.73 wt.%), MgO (0.38–0.90 wt.%), P2O5 (0.14–0.83 wt.%), MnO (0.04–0.57 wt.%). Additionally, they showed enrichment of LILEs (such as Rb, Ba, Th, U, and K), depletion of HFSEs (such as Ta, Nb, P, Ti, and Hf), no alkaline dark minerals, and the characteristics are typical of intraplate A1-type granite. The A1-type granite displayed low zircon εHf(t) values (-19.42– -15.02) with zircon two-stage Hf model aged 3.10–2.76 Ga, indicating that the U-rich granitic pegmatite was derived predominantly from partial melting of the ancient continental crust (such as the early Taihua group formed in Archean-Neoarchean). Combined with the above results and regional geological data, the U-rich granitic pegmatite discovered in the Huayangchuan deposit was related to granite magma activity that formed in a post-collisional regime after the Luliang movement in the late Palaeoproterozoic. This study suggests that future uranium prospecting work in this area should focus on late Palaeoproterozoic U-rich granitic pegmatites.

Modern surface analysis techniques are expanding significantly possibilities in description and attribution of historical artifacts. The present study is aimed to compare analytical ability of the X-ray fluorescent analysis (XRF) typically applied for studies ceramic art items with novel surface analysis methods: time-of-flight secondary ions mass spectroscopy (SIMS) and X-ray photoelectron spectroscopy (XPS) that were applied on measurements of elemental compositions of powder raw materials for porcelain fabrication: pegmatite P-1, Vesco-prima clay, kaolin, bone earth, dolomite, and feldspar. It was shown that SIMS successfully measures light elements unnoticeable for XRF such as lithium, beryllium, boron and heavy impurities not found out by XRF such as cobalt, cerium, copper, rubidium, vanadium. XPS has found thorium in the kaolin sample that was not detected by SIMS and XRF. The paper provides also values of chemical shifts of some XPS lines observed in materials under examination. The obtained information on relations of basic and impurity elements revealed by XRF and SIMS together with XPS chemical shifts data could be used to expose contemporary falsifications of historical porcelain and to attribute porcelain items during conservation process.