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Lithium is one of the important strategic energy metals, which is in short supply in China. There are three major types of lithium deposits: brine and salt lake type, highly differentiated granite or pegmatite type, and carbonate-clay type. In recent years, some new types of lithium deposits have also begun to receive great attention and subject recent research. There are many crypto-explosive breccia pipe type deposits in the world, including copper, gold, lead, zinc, tungsten and tin deposits, but little is known about this type of lithium deposit. This paper introduces the latest research results of the Weilasituo Sn−Li−Rb polymetallic deposit in Inner Mongolia (NE China), which occurs in the middle-southern section of the Great Xing'an Range metallogenic belt. A remarkable feature of this deposit is the coexistence of various mineralization types, including granite type Rb and Sn−Zn, hydrothermal crypto-explosive breccia pipe type Li−Rb, quartz vein type Sn−Zn and sulfide vein type Pb−Zn−Ag mineralization. Among them, hydrothermal crypto-explosive breccia pipe type Li-Rb deposit is currently very rare at home and abroad, which is likely a new type of rare metal deposit that worthy of our attention. This paper systematically summarizes the geology, alteration and mineralization, geochemistry, isotopes and geochronology of the Weilasituo deposit, and establishes a new petrogenic and metallogenic model. [ABSTRACT FROM AUTHOR]

The spatial distribution characteristics of heavy metals (As, Cd, Cu, Pb, and Zn) in a typical lead-zinc mine located in Inner Mongolia were studied by applying mathematical statistics and the ArcGIS spatial interpolation analysis. The Nemerow index and potential ecological-risk index were applied to the pollution assessment of heavy metals from the soil in accordance with the Environmental Quality Standard for Soils of China (grade 2) and background value for heavy metals. Results indicated that the average concentrations of As, Cd, Cu, Pb, and Zn were 82.39, 1.01, 33.47, 96.47, and 254.64 mg kg−1, respectively, and these values were higher than the regional background values in the studied scale. The average single-factor index (Pi) values of As, Cd, Cu, Pb, and Zn were 6.46, 6.61, 1.81, 3.93, and 4.02, respectively, when the regional background value was used as the assessment standard. Based on the Nemerow pollution index (PN), all areas over the mine were in moderate or heavy pollution. The result of potential ecological-risk assessment showed that the mining-activity area and its surrounding areas were in the moderate risk level or above. Pollution was concentrated in the centre mining-activity area of tailing reservoir, concentrator, and waste dumps. The degree of heavy-metal pollution decreased with increased distance from the mining-activity area. [ABSTRACT FROM AUTHOR]

[Display omitted] • Textural and chemical features of beryl can trace magmatic-hydrothermal evolution. • Cs in beryl is an ideal trace element to monitor the magmatic evolution. • Fluid exsolution can promote the remobilization of Ta and Rb. In the large Shihuiyao Rb-Nb-Ta-Be deposit, a beryl-bearing granite was identified with three texturally different zones that show an increasing degree of fractionation, including the albite granite (bottom zone), albite granite with pegmatite pockets (intermediate zone), and intercalation of granite and pegmatite layers (top zone). Beryl occurs both in the intermediate and top zones. Microtextural (SEM), Raman spectra, and trace-element (LA-ICP-MS) data on beryl from these zones shed new light on the behavior of trace elements during magmatic-hydrothermal evolution. In the intermediate zone, magmatic beryl (Brl-1) has a homogeneous texture, while beryl in the top zone (Brl-2) can be divided into magmatic (Brl-2a) and metasomatic subtypes (Brl-2b). The magmatic Brl-2a shows oscillatory zonation, whereas the metasomatic Brl-2b is darker in BSE images and highly porous. Fractional crystallization led to an increase in Na, Sc, Fe, Rb, and Cs contents from Brl-1 to Brl-2a. Comparing these data with those of beryl in other pegmatites worldwide reveals that Cs in beryl is an ideal trace element to monitor the magmatic evolution of the pegmatite host. Distinct textural and chemical features of Brl-2a and Brl-2b reflect metasomatic alteration by a dissolution-reprecipitation process for Brl-2b. In combination with published experimental and fluid inclusion data, we propose that metasomatic fluids exsolved from the magma during late-magmatic stages could transport large amounts of rare metals, such as Ta and Rb. The higher content of Ta in Brl-2b compared to Brl-2a suggests that metasomatic fluids exsolved from the magma play a favorable role in Ta mineralization. In contrast, decreasing Rb contents in Brl-2b is attributed to the high mobility of Rb in the fluid. Such Rb-rich fluids are expected to generate Rb orebodies of economic value surrounding the ore-bearing granite, implying that more investigation into hydrothermal Rb mineralization in the Shihuiyao district is warranted. [ABSTRACT FROM AUTHOR]

Abundant tourmaline occurs in the Mopanshan pluton in Inner Mongolia of NE China, and can be classified by its occurrence into four types: nodular tourmalines (ND type), pegmatite-pocket tourmalines (PP type), stockwork tourmalines (SW type) and vein tourmalines (VT type). All these tourmalines belong to the alkali group and are dravite-schorl. Petrography and major elements data suggest that the ND- and PP-type tourmalines crystallized during the transition from late-magmatic to early-hydrothermal evolution of granite with all the components derived from the magma. Petrography and trace elements (especially Sr、V、Cr、Ni、Ti) data suggest that the SW- and VT-type tourmalines may form by the mixing of magmatic and country rocks components in the post-magmatic hydrothermal environment. Due to the similar δ11B of the SW-type with the ND- and PP-type tourmalines (variation <2‰, and all averaged at −15.8‰), the boron source of the SW-type tourmalines is likely the same as the ND- and PP-type ones, i.e., from the granitic magma. The VT-type tourmalines have extremely negative δ11B values from −27.0‰ to −29.8‰, indicating a distinct and isotopically lighter boron source. The potential presence of non-marine evaporites (with very light boron isotopes) in the meta-sedimentary strata deep in the region may contribute boron to the VT-type tourmalines. The high Sn contents in the tourmalines, in particular the SW-type (918–2172 ppm) may have prospecting significance to target tin mineralization related to granite in the region. Image 1 • Four types of tourmaline occurrences are associated with the Mopanshan pluton. • The tourmalines formed from late-magmatic or post-magmatic hydrothermal fluids. • The Mopanshan tourmalines have high Sn contents up to 2172 ppm. • The tourmalines source their B from two isotopically distinct sources. [ABSTRACT FROM AUTHOR]