Yunnan Province, China, harbors numerous ancient plateau lakes, some of which have dried up. Recent research has uncovered a wealth of gastropod fossils from these desiccated lake basins, with most representing Yunnan-endemic species. For the family Viviparidae, these subfossils and fossils typically possess large shells, a trait that facilitates their preservation in deeper clay layers. This study investigated ancient lake basins in Qujing, Mengzi, and Zhaotong cities, Yunnan Province. Viviparidae specimens were collected from different stratigraphic layers to explore the evolutionary patterns of shell morphology in endemic species of these ancient lakes. The study describes fifteen new species: Anularya bengu H.-Q. Xiang, B.-Y. Wang, Y.-M. He & A.-S. Lv sp. nov., Cipangopaludina somnumbra H.-Q. Xiang, B.-Y. Wang, Y.-M. He & T.-X. Xie sp. nov., Dalipaludina zhanglejiai H.-Q. Xiang, B.-Y. Wang, Y.-M. He & H. Chen sp. nov., Dalipaludina zhaolu H.-Q. Xiang, B.-Y. Wang, Y.-M. He & H. Chen sp. nov., Tchangmargarya ashimaae H.-Q. Xiang, B.-Y. Wang, Y.-M. He & H. Chen sp. nov., Tchangmargarya buhou H.-Q. Xiang, B.-Y. Wang, Y.-M. He & L.-R.-X. Chen sp. nov., Tchangmargarya cunshan H.-Q. Xiang, B.-Y. Wang, Y.-M. He & A.-S. Lv sp. nov., Tchangmargarya sparkleae H.-Q. Xiang, B.-Y. Wang, Y.-M. He & H. Chen sp. nov., Tchangmargarya laojin H.-Q. Xiang, B.-Y. Wang, Y.-M. He & H. Chen sp. nov., Tchangmargarya liyoufui H.-Q. Xiang, B.-Y. Wang, Y.-M. He & H. Chen sp. nov., Tchangmargarya luyizhii H.-Q. Xiang, B.-Y. Wang, Y.-M. He & H. Chen sp. nov., Tchangmargarya mohou H.-Q. Xiang, B.-Y. Wang, Y.-M. He & L.-R.-X. Chen sp. nov., Tchangmargarya yangjizhoui H.-Q. Xiang, B.-Y. Wang, Y.-M. He & H. Chen sp. nov., Tchangmargarya yumi H.-Q. Xiang, X.-C. Zha, Y.-M. He & H. Chen sp. nov., Tchangmargarya zhangxianmingi H.-Q. Xiang, X.-C. Zha, Y.-M. He & H. Chen sp. nov. The species previously known as Tulotomoides tulotomoides (Yen, 1935), Idiopoma tingi (Yen, 1935) and Idiopoma chutsingensis (Yen, 1935) are moved to Tchangmargarya J. He, 2013 genus; Idiopoma wangi (Yen, 1935) syn. nov. being assigned as a junior synonym of Tchangmargarya tingi comb. nov.; Vivipara margaryaeformis Mansuy, 1918 is moved to the Anularya Zhang & Chen, 2015 genus.

Nanhong agate has attracted public attention as the most distinctive gemstone in China. Owing to the limited data on Nanhong agates from a new production area in northeastern Yunnan, this paper presents the first data from gemological studies on these agates. Complex investigations using Fourier-transform infrared (FTIR) spectrometry, ultraviolet–visible (UV–VIS) luminescence spectrometry, Raman spectroscopy, polarizing microscopy, scanning electron microscopy (SEM), electron microprobe (EPMA), and laser ablation–inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses were carried out to obtain basic data concerning the gemological properties, microstructure, and spectroscopic and geochemical characteristics of this interesting material. The results illustrate that Nanhong agates from northeastern Yunnan are mainly composed of α-quartz and also contain certain amounts of moganite, illite, goethite, and hematite. The typical red (yellow) and white appearance can be attributed to the microstructure of the agates, the contents of Fe and Al impurities, and trace elements. The Raman spectra, microstructure, and chemical composition of the unique “yellow-skinned” agates from northeastern Yunnan are significantly different from those of other types of Nanhong agate. This work lays a foundation for the future identification and research of this type of Nanhong agate.

Yuanjiang County is one of the most important gem-producing areas in China. The authors of this study discovered and collected gem-quality andradite Garnsts in the epidote amphibolite from the periphery of the ruby deposit in Shaku Village, Yuanjiang County. After careful observation of the collected andradite, it was found that these andradite samples appear green when the thickness is less than 2 mm and reddish-brown when the thickness is greater than 2 mm, exhibiting the typical Usambara effect. To investigate the gemological and spectroscopic characteristics of Yuanjiang andradite, this study conducted basic gemological tests, microscopic observation, electron probe microanalysis (EPMA), ultraviolet–visible (UV-Vis) absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and laser Raman spectroscopy on the collected samples. Tests show that Yuanjiang andradite has a lower specific gravity than typical andradite, which is due to the presence of epidote inclusions inside. EPMA results indicate that the samples contain a certain amount of Cr element. The crystal chemical formula of the samples calculated from the EPMA results is (Ca2.89–2.93, Mn0.01–0.02, Fe0.15–0.10)(Fe1.69–1.95, Al0.00–0.23, Cr0.00–0.23, Si0.05–0.08)(SiO4)3. UV-Vis tests show that the samples have transmission windows in both the green- and red-light regions, with Fe3+ and Cr3+ acting as the main chromogenic ions, among which Cr3+ is crucial for the occurrence of the Usambara effect. The FTIR and Raman test results are basically the same as previous research results, but some peak positions related to metal cations differ from the theoretical values, which may be caused by the presence of a certain amount of Cr3+ in the samples.

The Bozhushan in southeastern Yunnan is a composite granite body that was formed by multi-phase magmatic intrusion. The genesis of the tourmaline-supergroup minerals occurring therein remains uncertain, as it has been the subject of only a limited number of studies. This investigation employs an integrated analytical approach combining EPMA, LA-ICP-MS, and boron isotope geochemistry, supplemented by detailed field geological investigations and petrographic observations of tourmaline textural characteristics. This study aims to elucidate the genetic relationships between distinct tourmaline varieties, establish temporal correlations between mineral crystallization stages and magmatic–hydrothermal evolution processes, and evaluate the petrogenetic significance of tourmaline geochemical signatures for regional mineralization events. This study analyzes tourmaline-supergroup minerals in granitic pegmatites and aplites, which occur as nodular, radial, and columnar aggregates. Most tourmaline crystals exhibit well-defined rhythmic zoning patterns, which are clearly observable under cross-polarized light microscopy. Chemical composition analysis has identified two tourmaline species: schorl and dravite. The formation of tourmaline is primarily of magmatic origin and is characterized by a magmatic–hydrothermal transition. It predominantly belongs to the alkali subgroup and is formed in Li-poor granitoids and associated pegmatites and aplites, Ca-poor metapelites, metapsammites, and quartz-tourmaline rocks. The inter-ionic substitution mechanism in this system is predominantly governed by Fe²⁺Mg₋₁ and (X_vacAl)(NaR²⁺)₋₁ exchange equilibria. Additionally, geochemical evidence indicates that the primary ore-forming fluids originate from granitic magmas, which are likely sourced from the partial melting of metasedimentary rocks. During the late Yanshan period, the upwelling of granitic magma in the Bozhushan area introduced a substantial heat source and mineralizing fluids, which interacted with the Cambrian units to form tungsten–tin mineralization. The geochemical data on tourmaline indicate that the Bozhushan granite body has considerable potential for ore mineralization.

The Posongchong Flora is an important window for understanding early vascular plant evolution. During a recent investigation of the Feigucun Section in the Bainiuchang area, Southeastern Yunnan, the author’s team discovered a large number of plant fossils from the Posongchong Formation of the Pragian Stage, Lower Devonian Series. Among the fossils collected in this investigation, there are six morphologically distinct drepanophycalean fossils, characterized by irregular dichotomous branching forming clustered stems, with the surface of the stems densely covered with spirally arranged falcate leaves. After comparing with coeval plant fossil records, it was found that the above characteristics are consistent with the generic characteristics of Hueberia fossils found in the Posongchong flora, indicating that these specimens should be assigned to the genus Hueberia. The team compared the newly discovered Hueberia fossils with the previously described Hueberia zhichangensis. The comparison revealed that the Hueberia specimens collected in the Bainiuchang area have thicker stems, longer intervals between successive branchings, and certain differences in leaf morphology from Hueberia zhichangensis. Therefore, the team considers that there are significant differences between it and Hueberia zhichangensis in morphology, geographical distribution, and other aspects, and there is sufficient reason to erect a new species, Hueberia bainiuchangensis sp. nov. The discovery of this species enriches our understanding of the species diversity of the genus Hueberia, expands the geographical distribution range of the Posongchong Flora, further corroborates that the Southeastern Yunnan region had extremely high biodiversity during the Pragian Age of the Early Devonian, and provides new clues for the study of Early Devonian plant evolution.

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.