The Xiaotunxiang deposit, a newly discovered large-scale fluorite resource (1.28 Mt ore reserves) in southwestern Guizhou Province, China, provides a critical case study for understanding fluorite mineralization in the region. To constrain its genesis, this study integrates detailed ore deposit geology with mineralogy, trace element geochemistry, and strontium isotope analysis of fluorite. The ore mineral assemblage is dominated by fluorite, quartz, and calcite, with minor amounts of barite and pyrite. Trace element data reveal significant enrichment in Ti, Cr, Mo, and Sb relative to the upper continental crust. Fluorite exhibits moderate total REE contents (26.8–138 ppm), slight heavy REE enrichment (ΣLREE/ΣHREE = 0.17–1.88), pronounced negative Ce anomalies (δCe = 0.59–0.72), and negligible Eu anomalies (δEu = 0.95–1.14). These geochemical signatures are closely comparable to those of nearby fluorite deposits (Qinglong, Gaoling, and Getang), indicating a shared source of ore-forming materials. Strontium isotope ratios (⁸⁷Sr/⁸⁶Sr = 0.707468–0.707682) are consistent with local carbonate wall rocks, confirming their role as the primary source of calcium. We conclude that the Xiaotunxiang deposit formed from a low-temperature hydrothermal system where fluorine and associated metals were likely sourced from the Emeishan basalts, while calcium was derived from the interaction of acidic fluids with carbonate host rocks. Precipitation was ultimately triggered by fluid–rock (water/rock) interaction, classifying Xiaotunxiang as a carbonate-hosted hydrothermal deposit.

The Guanfang tungsten deposit in the Bozhushan ore district, southeastern Yunnan, is genetically linked to Late Yanshanian granitic intrusions. To elucidate the petrogenesis and mineralization potential of the causative granite, this study presents a detailed mineral chemical analysis of biotite from the Guanfang pluton using electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The biotite crystals exhibit relatively high euhedrality, show no obvious alteration features, and are chemically characterized by reduced Na and Ca contents. These features, along with petrographic observations, confirm its origin as primary magmatic biotite. Crystallization conditions, calculated from biotite chemistry, indicate temperatures of 700–720 °C and pressures of 1.22–1.73 kbar, corresponding to a mesozonal emplacement depth of 4.6–6.5 km. Oxygen fugacity estimates, plotting near the Ni-NiO buffer, reveal an oxidized magmatic environment. Geochemical discrimination diagrams suggest the Guanfang granite exhibits transitional features between S-type and I-type affinities and is classified as a syn-melting (high-temperature) type. The biotite contains relatively low F (0.71–0.97 wt%), but elevated Cl (0.13–0.20 wt%) and Sn (43–56 µg/g) contents. This specific geochemical signature—combined with the medium- to high-temperature crystallization setting—is highly favorable for W-Sn mineralization. Furthermore, the high-Ti, syn-melting character of the granite implies additional potential for Cu-Pb-Zn-Au-Ag polymetallic mineralization. This study employs biotite chemistry to assess the petrogenesis and metallogenic potential of the Guanfang granite. The subsequent discovery of industrial ore bodies corresponding to some of the elements identified as having metallogenic potential confirms the feasibility of this approach. Accordingly, this method provides a new tool for future exploration in the Bozhushan district.

We report the discovery of a new palaeoscolecid worm specimen from the Bainiuchang area, southeastern Yunnan, China. The specimen exhibits a cylindrical body with annulations, each bearing two rows of Hadimopanella-type sclerites, along with plates, platelets, microplates, and implanted plates. These features are compatible with the diagnosis of the genus Wronascolex, and the specimen is tentatively assigned to Wronascolex sp. However, given the limited number and preservation of the available specimens, which preclude a detailed demonstration of the scleritome morphology for comparison with other palaeoscolecid worms, this assignment should be treated as tentative. This specimen may be the first record of a soft-bodied fossil from the Miaolingian Series (Wuliuan Stage) strata of southeastern Yunnan. Its taphonomic features—preservation as carbonaceous compressions accompanied by iron-rich films—are broadly consistent with Burgess Shale-type (BST) preservation. Whole-rock geochemical analysis of samples from the fossil-bearing interval yielded redox proxy values suggestive of suboxic to weakly reducing depositional conditions, broadly comparable to those reported from some BST deposits, such as the Mackenzie Mountains locality of Canada. However, these geochemical results are preliminary and based on a limited number of samples. Taken together, these observations suggest the possibility that the Bainiuchang area may host a BST Lagerstätte. Should this be confirmed, such a deposit would postdate the Chengjiang and Guanshan biotas (Cambrian Series 2, eastern Yunnan) and predate the Fulu biota, which is the only confirmed BST Lagerstätte in southeastern Yunnan to date. Furthermore, this discovery extends the known paleogeographic range of the genus Wronascolex southward to the southwestern margin of the South China Block. It also represents, to our knowledge, the first reported occurrence of soft-bodied fossil preservation in the Wuliuan Stage of Yunnan Province.

The Sar-e-Sang lapis lazuli deposit has a mining history exceeding 5000 years, producing the world’s finest lapis lazuli. Recently, gem-quality forsterite has been discovered in the marble containing spinel, dolomite, and phlogopite at the periphery of the lapis lazuli ore body at the Pitawak mine, located east of the Sar-e-Sang deposit. The mineral assemblage indicates that the protolith of this marble is dolomite with aluminous and siliceous components. These forsterite crystals occur as colorless, transparent anhedral grains, exhibiting distinct red fluorescence under 365 nm ultraviolet light. To investigate the gemological and spectroscopic characteristics of the Pitawak mine forsterite, this study conducted and analyzed data from basic gemological analysis, electron probe microanalysis (EPMA), Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), ultraviolet–visible absorption spectroscopy (UV-VIS), Fourier-transform infrared spectroscopy (FTIR), laser Raman spectroscopy (RAMAN), and photoluminescence spectroscopy (PL) on four forsterite samples from the Pitawak mine. The analysis results reveal that the samples indicate a composition close to ideal forsterite with a crystal chemical formula of (Mg_2.00Fe_0.02)_Σ2.02Si_0.99O₄. The trace elements present include Fe, Mn, Ca, and minor amounts of Cr and Ni. The UV-VIS spectroscopy results show that the samples possess high transmittance across the visible light range with very weak absorption bands, contributing to the colorless and transparent appearance of Pitawak mine forsterite. This phenomenon is attributed to the extremely low content of chromophoric elements, which have a negligible effect on the forsterite’s color. PL spectroscopy indicates that the red fluorescence of the samples is caused by an emission peak near 642 nm. This emission peak arises from the spin-forbidden ⁴T₁ → ⁶A₁ transition of Mn²⁺ ions situated in octahedral sites within the forsterite structure.