Northeastern Yunnan Research Articles

Clematis jialasaensis var. macrantha and C. napoensis (Ranunculaceae), another two new synonyms of C. armandi from China

Based on consultation of literature, survey of specimens (including type material), and observations of living plants in the wild, we confirm that Clematis jialasaensis var. macrantha and C. napoensis (Ranunculaceae), described respectively from northeastern Yunnan and southwestern Guangxi, China, actually belong to C. armandi, a species widely distributed in the country. We therefore place both C. jialasaensis var. macrantha and C. napoensis in synonymy with C. armandi. We also determine that two collections of Clematis, J.M. Delavay 4 and J.M. Delavay 5146, from Tchen-fong Chan in northeastern Yunnan, China, the type locality of C. jialasaensis var. macrantha, also belong to C. armandi. These two collections have been previously referred to C. meyeniana or C. finetiana.

A new post-LOME (Late Ordovician Mass Extinction) recovery brachiopod fauna from South China

AbstractFollowing the Late Ordovician Mass Extinction event, brachiopod faunas were in a phase of recovery during the late Rhuddanian (early Silurian), documented by a drastic turnover of Ordovician-type to Silurian-type faunas. In this study, we present a recovery brachiopod fauna, from the Niuchang Formation (late Rhuddanian-based graptolite zonation) at the Wanzi section of Zhenxiong in northeastern Yunnan Province, South China. The fossils include 26 species assigned to 25 genera, with a dominance of strophomenides and orthides, but also a diverse suite of atrypides and pentamerides, which exhibit compositional differences compared to the earlier Edgewood–Cathay fauna. The emergence of a more typical Silurian brachiopod fauna suggests a delayed community turnover after the Late Ordovician Mass Extinction event. The shallowing marine environment trend evinced in the brachiopod assemblages in the section indicates a balance between the global transgression and the regional Qianzhong Uplift, which provided a stable environment for the brachiopod recovery. The presence of diverse pentamerides, including the earliest species of the large-shelled genus Sinostricklandiella, suggests early diversification of this clade in South China.

Origin of Color and Spectral Characteristics of Nanhong Agate from Northeast Yunnan, China

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.

Environment and management jointly shape the spatial patterns of plant species diversity of moist grasslands in the mountains of Northeastern Yunnan

Grasslands account for about a quarter of the Earth’s land area and are one of the major terrestrial ecosystems, with significant ecological and economic value. The influence of environmental factors and management types on grassland biodiversity has garnered considerable attention. This study investigated how patterns of species richness are influenced by geographical distance, environmental gradients, and management type in the grasslands of northeastern Yunnan, China. We used structural equation modeling to disentangle the impacts of environment and management on phylogenetic community structure, and partial Mantel tests to estimate the roles of dispersal limitation and environmental filtering on taxonomic and phylogenetic beta diversity of three types of grasslands. Our results show that taxonomic alpha diversity increased in grazed grasslands and decreased in mowed grasslands, compared with protected grasslands. However, the phylogenetic structure of both grazed and mowed grassland communities was clustered, whereas that of protected communities was random. Moreover, both grazing and mowing significantly reduced the taxonomic and phylogenetic beta diversity of grasslands, with the lowest values observed in mowed grasslands. Both taxonomic and phylogenetic beta diversity were dominated by species turnover under different management types. The taxonomic and phylogenetic beta diversities of protected and grazed grasslands were simultaneously affected by environmental filtering and dispersal limitation, with the later playing a stronger role. In addition, mowing and related management measures had a stronger filtering effect on grassland community structure, as reflected by changes in community composition.

Mineralogical and geochemical composition of the early carboniferous Li-enriched coals of the Zhaotong coalfield, Northeast Yunnan, China

The Middle and Lower Carboniferous sedimentary sequences in the central and western parts of Guizhou, southwest China, are enriched in bauxite, and are characterized by increased levels of the critical element Li. In the adjacent area (northeastern Yunnan), the Lower Carboniferous sequences contain coal seams. Whether these coal seams are enriched in Li, and the provenance affinity between the bauxites and these coal seams are still unclear. In this study, the mineralogy and geochemistry of the C1 coal seam in the Wanshoushan Formation, Lower Carboniferous sedimentary sequences, Zhaotong Mining Area, northeastern Yunnan Province, were investigated. The results showed that the major minerals in the C1 coal seam are clay minerals, Al-bearing minerals, quartz, pyrite, and so on, most of which are of authigenic origin. This coal seam was enriched in Li, Cu, Zn, and so on with the Li concentration coefficient reaching to 8.92. The trace elements in the C1 coal seam of the Wanshoushan Formation and the elements in the bauxites of the Jiujialu and Dazhuyuan Formations were similar, and their provenance was the underlying Cambrian - Ordovician carbonate rocks.

Source analysis and contamination evaluation of potentially toxic elements in soil in typical high geological background areas at the county scale in northeastern Yunnan, China

The pollution risk of potentially toxic elements (PTEs) in soil is a common concern in the fields of environmental science and agriculture. The spatial distribution characteristics, pollution risk assessment and genetic sources of PTEs in soil in high geological background areas are crucial to the safe use of land. Based on the data for five PTEs in 921 surface soil samples from typical high geological background areas in SW China, we discuss their spatial distribution characteristics using geostatistics, the semivariance function and its model. We carry out pollution risk assessment using the influence index of comprehensive quality (IICQ) and analyse their genetic sources using the UNMIX receptor model. The spatial distribution of element content has a high spatial coupling with the stratigraphic spread, which is affected by external random factors, resulting in a weakened autocorrelation. The IICQ indicates that soil is dominated by mild and moderate pollution, accounting for 42.24 and 44.95%, respectively, with cadmium contributing up to 63.00% to the IICQ. Chromium and cadmium are controlled by natural sources, accounting for 83.98 and 69.39%, respectively. Arsenic and mercury have anthropogenic sources, accounting for 68.7 and 44.0%, respectively. Lead is controlled by both lead–zinc mining and geological background, accounting for 47.7 and 36.4%, respectively. The UNMIX model demonstrates that the spatial variability of PTEs is influenced by anthropogenic factors, such as coal combustion emissions, which account for 30.1% of the pollution sources. Soil parent material sources contribute 49.4%, followed by lead–zinc mining and smelting activities at 20.5%.

Oblique distribution patterns and the underlying mechanical model of orebody groups controlled by structures at different scales

The oblique distribution of orebodies is a basic feature of the spatial distribution of orebody groups in hydrothermal deposits, and it is closely related to the shearing effect. However, the oblique distribution patterns of orebody groups controlled by ore-controlling/ore-forming structures at different scales (orebody, ore deposit and ore field scales) and the underlying formation mechanism are unclear but could be used to directly constrain mineral exploration and prospecting breakthroughs in the deep and peripheral areas of ore deposits. This paper uses the northeastern Yunnan Ge-rich Pb–Zn ore concentration area in the Sichuan–Yunnan–Guizhou metallogenic area as an example to analyse and demonstrate the oblique distribution patterns of orebodies (orebody groups) controlled by ore-forming/ore-controlling structures at different scales and the underlying mechanical model based on the Theory and Methods of Ore field Geomechanics. The results indicate that in 3D space, the oblique distributions of orebodies (veins), orebody groups and ore deposits are controlled by the mechanical properties, kinematic characteristics, and tectonic stress fields of ore-forming/ore-controlling fault structures of different sequences during the mineralization period. This study has an important guiding role for ore field-scale exploration deployment, evaluation of deep and peripheral prospecting, and exploration project arrangement, with the aim of helping mining companies increase resource reserves and production.

Numerical simulation of fault-fold structures controlled ore formation: Case studies of the Huize and Maoping lead-zinc deposits in Northeastern Yunnan Province, southwest China

Understanding the intricate relationship between fault-fold structures and ore body localization is paramount in economic geology. However, there is a lack of quantitative data on the influence of the geometry characteristics of faulted fold structures on the migration of ore-forming fluids. In this study, the differential ore-controlling characteristics of the steep flank of the anticline (Huize fault-fold belt,the ore body is located in the SE flank of the anticline) and the overturned flank of the anticline(Maoping fault-fold belt, the ore body is located in the NW flank of the anticline) were studied by using multi-physical finite element numerical simulation method. The findings of the study indicate that:(1) The local pressure anomalies in the core and southeastern flank of the Huize fault-fold belt is relatively higher than in comparable elevations elsewhere, while pressure anomalies in the Maoping fault-fold belt are concentrated in the core of the folds. (2) In the internal fault-fold belt of Huize, there is no significant temperature difference on either side of the folds. However, in the Maoping fault-fold belt, after reaching the core, heat predominantly transfers to the top pressure anomaly zone, resulting in noticeably higher temperatures in the northwest flank compared to the southeast flank. (3) Within the Huize fault-fold belt, ore-bearing fluids initially migrate along the fault, then move towards the core and SE flank upon reaching the mineralized strata. In contrast, within the Maoping fault-fold belt, ore-bearing fluids, after entering the layers, primarily migrate towards the core. (4) In the Huize ore deposit, the concentration of Zn2+ is significantly higher in the SE flank than in the NW flank, while in the Maoping deposit, the concentration is higher in the NW flank. The research results align with geological facts and provides valuable insights into the quantitative analysis of ore distribution controlled by the fault structure. This study provides crucial insights into exploring the control and influence of differential structural deformation on ore-bearing fluid migration, offering favorable exploration targets.

Numerical simulation of Huize germanium-enriched lead-zinc deposit formation and its implications for concealed zinc mineralization distribution and controlling factors in northeastern Yunnan Province, southwest China

The Huize germanium-enriched Pb–Zn deposit is globally recognized as a high-grade and supergiant Pb–Zn deposit, boasting reserves exceeding 7 Mt of Pb and Zn at an ore grade ranging from approximately 25 % to 35 % Pb + Zn. Employing numerical simulation methods, we investigate factors challenging identification through conventional approaches in elucidating the formation of the Huize deposit ore-forming system. Within a multi-field coupling framework integrating thermal and fluid dynamics, our objective is to faithfully reproduce the intricate process of ore-bearing fluid migration. This study unveils the principal controlling factors governing the distribution of ore bodies (sphalerite) within a defined fault-fold structure. Our model establishes a link between the four elements of the ore body formation process: Time-Space-Material-Evolution, highlighting the presence of temperature and barotropic stress anomalies in fluid convergence, with Zn2+ spatial distribution correlating with known mineralization distribution. Numerical simulation experiments indicate that, under the influence of thermal flow fields and pressure, the migration of ore-bearing fluids may result in mineral enrichment in areas exhibiting significant barotropic stress anomalies. These areas, characterized by favorable mineralization conditions, offer an explanation for the observed differences in mineralization between the southeast and northwest flanks of the Kuangshanchang fault-fold structure. Our findings present a novel methodology for conducting further in-depth research on predicting concealed lead–zinc deposits in the Huize area.

A new species of Dichocarpum (Ranunculaceae) from northeastern Yunnan, China

A new species of Ranunculaceae, Dichocarpum yongshanense, is described and illustrated from northeastern Yunnan, China. Morphologically, it is similar to Dichocarpum hypoglaucum, but differs from the latter by its two basal leaves, membranous and abaxially non-pruinose leaf blade, and pinkish sepals. The new species is assessed to be Endangered (EN) according to IUCN categories and criteria.

Geological and Geochemical Characteristics and Genesis of the Laoyingqing Zinc Deposit in Northeastern Yunnan

The Laoyingqing zinc deposit is located in the Pb-Zn deposit concentration district in northeastern Yunnan, with a geotectonic location on the southwestern edge of the Yangtze block. This deposit occurs in the interlayer fracture zone of the Huangcaoling Formation slate in the Middle Proterozoic Kunyang Group. In this deposit, zinc is significantly enriched compared to lead, and the sulfur isotopic composition of sphalerite shows δ34SCDT close to negative values. These characteristics are different from the common Pb-Zn deposits that occur in Sinian and Carboniferous carbonate rocks in northeastern Yunnan. The genesis of this deposit and its similarities to and differences from other Pb-Zn deposits hosted in carbonate rocks in the Sichuan–Yunnan–Guizhou Pb-Zn metallogenic triangle area (SYGT) need further research. This article selects typical rock (ore) samples for fluid inclusion, trace element, and H–O isotope analyses. The results show that (1) the homogenization temperature of the fluid inclusions is 130~306.5 °C, the salinity is 7.17 wt%~20.67 wt% NaCleq, and the density of the ore-forming fluids is 0.86–1.07 g/cm3. Overall, these ore-forming fluids belong to medium–low-temperature, medium–low-salinity, and medium–low-density ore-forming fluids, and they have reducibility. The fluid pressure is 36.3~85.6 Mpa, and the mineralization depth is 1.34~3.17 km. (2) The ore-forming fluids mainly came from deep-source metamorphic water and basin brine containing organic matter. (3) The ore-forming materials mainly came from the surrounding rocks (Kunyang Group). (4) The trace element characteristics of this deposit are different from sedimentary-exhalative type, magmatic hydrothermal type, and skarn type of Pb-Zn deposits, and have little difference from MVT Pb-Zn deposits. Based on the comprehensive analysis, this deposit is classified as a medium–low-temperature hydrothermal vein-type zinc deposit unrelated to magmatic activity. This study extends the ore-bearing surrounding rocks of Pb-Zn deposits in the SYGT to the slate of the Kunyang Group, enriching the regional Pb-Zn deposit mineralization theory and providing new ideas for mineralization prediction.

Synotisjinpingensis (Asteraceae, Senecioneae), a new species with white ray florets from southeastern Yunnan, China.

Synotisjinpingensis (Asteraceae, Senecioneae), a new species from Jinping county in southeastern Yunnan province, China, is described and illustrated. This species is distinguished by having white ray florets in the genus Synotis, in which only species with yellow ray florets have been hitherto known. In habit and leaf shape S.jinpingensis is most closely similar to S.duclouxii, a species occurring in southwestern Guizhou, southern Sichuan and northeastern Yunnan, China, but differs, in addition to the color of ray florets, by having fewer lateral veins of leaves, obviously longer bracts of calyculus, and larger phyllaries. The membership of the new species within Synotis is strongly corroborated by evidence from floral micromorphology and phylogenetic analyses based on ITS sequence data. Color photographs of living plants, a distribution map, and provisional IUCN status of S.jinpingensis are provided.

Metallogenic Model for Pb-Zn Deposits in Clastic Rocks of the Dahai Mining Area, Northeast Yunnan: Evidence from H-O-S-Sr-Pb Isotopes

The Dahai Pb-Zn mining area is located in the northwestern Pb-Zn district in northeastern Yunnan Province in the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic triangle (SYGT), east of the Xiaojiang fault. Numerous Pb-Zn deposits (spots) occur in clastic rocks in this area. In this study, the Maliping, Laoyingqing, and Jinniuchang Pb-Zn deposits, representative clastic rocks in the Dahai mining area, were selected as research objects. The results of H-O-S-Sr-Pb isotope analyses show that the three deposits mainly formed through the mixing of a basinal brine with a hydrothermal fluid derived from deep within the underlying (deformed) basement, and brines leached organic matter from wall rocks. The δ34S values range from −2.62–30.30‰. The S isotope results show two different sources of reduced S: one in the Laoyingqing deposit derived from the S reduction generated by the pyrolysis of sulfur-bearing organic matter in the carbonaceous slate of the Kunyang Group, and the second in the Maliping and Jinniuchang deposits derived from the S reduction generated by the thermochemical sulfur reduction (TSR) of seawater sulfate in the Lower Cambrian Yuhucun Formation and Sinian Dengying Formation. The Pb isotope results show that the Pb sources of the three deposits are derived from basement rocks (Kunyang Group) with a small portion derived from Devonian–Permian carbonate rocks and Dengying Formation dolomite, both of which have undergone homogenization during mineralization. The Sr content varied from 0.09629 to 0.2523 × 10−6, and the study shows that the main source of Sr is a mixture of ore-forming fluid flowing through basement rocks (Kunyang Group) and through sedimentary cover. However, most of the Sr in the Maliping deposit is derived from marine carbonate, and in the Laoyingqing deposit, it is provided by basement rocks (Kunyang Group). Based on a comparative study of the deposits, the Pb-Zn deposits in the clastic rocks of the Dahai mining area and the SYGT belong to the same metallogenic system and were formed under the same metallogenic geological background. Finally, a unified metallogenic model of the two types of fluid migration and mixed mineralization of the Pb-Zn deposit in clastic rocks of the Dahai mining area is proposed. The metallogenic model provides a basis for the study of the Pb-Zn metallogenic system and guidance for deep and peripheral prospecting in this area.

Distributional responses to climate change of two maple species in southern China.

Climate change is a major factor affecting biodiversity and species distribution, particularly of montane species. Species may respond to climate change by shifting their range to higher elevations. The southeastern Qinghai-Tibetan Plateau (QTP) and the Hengduan Mountains are considered as global biodiversity hotspots. However, information on the response of maple species to climate change in these regions was limited. Therefore, we selected two maple species that occur there and assessed changes in their habitat suitability under past, present and future climate scenarios in Biomod2. The results showed that temperature seasonality (bio4) was the most critical factor influencing their potential distributions. The distribution of potentially suitable habitat for Acer caesium and Acer stachyophyllum was predicted to be larger during the LGM compared to the present. Under the current climate scenario, the largest areas of potentially suitable habitat for these species were mainly located in southeastern Tibet, the Hengduan Mountains in northwestern Yunnan and western Sichuan, the Qinling-Daba Mountains in southern Gansu and the Wumeng-Daliang Mountains in northeastern Yunnan, western Guizhou and southeastern Sichuan. Under future climate change scenarios, the predicted loss of suitable habitat areas for these two species ranged from 13.78% to 45.71% and the increase ranged from 18.88% to 57.98%, with an overall increasing trend. The suitable habitat areas were predicted to shift towards the eastern parts of the QTP under both the pessimistic and optimistic future climate change scenarios in the 2050s and the 2070s, which became evident as global warming intensified, particularly in the eastern QTP and the Hengduan Mountains. Our results highlight the possibility that the diverse topography along altitudinal gradients in the QTP and the Hengduan Mountains may potentially mitigate the range contraction of mountain plants in response to climate warming. These findings provide a basis for planning conservation areas, planting and species conservation in the mountainous areas of southern China under the anticipated global warming.

Geology, geochemistry and genesis of the giant Maoping carbonate-hosted Pb-Zn-(Ag-Ge) deposit in northeastern Yunnan Province, SW China

The Maoping Pb-Zn deposit is spatially associated with the late Permian Emeishan basalts and structurally controlled by the NE-trending reverse fault-anticline tectonic system. Nevertheless, there remains limited comprehension of its genetic association with the Emeishan magmatism, as well as the coupling relationship between the overall metallogenic processes and geodynamic evolution. In order to clarify these scientific issues, the syn-ore hydrothermal calcites, sulfides, and sulfates were systematically collected from the representative No. I ore body at different elevations in the Maoping deposit for bulk C-O-S and in situ S-Pb isotopic analyses. Bulk C-O isotopic compositions of syn-ore calcite (δ13CV-PDB = − 4.94 to −0.81‰, δ18OSMOW = +17.66 to +21.16‰) and associated fluids (δ13CV-PDB = −4.56 to −0.48‰, δ18OSMOW = +8.63 to +12.13‰) indicate that C in fluids was mainly derived from ore-bearing carbonate rocks, whereas O was generated by fluid/rock (W/R) interaction process between initial fluids and carbonate rocks. Such process also triggered carbonate dissolution and syn-ore calcite precipitation. In situ Pb isotopic ratios of galena (208Pb/204Pb = 39.116–39.425, 207Pb/204Pb = 15.742–15.767 and 206Pb/204Pb = 18.603–18.753) are more comparable with those of ore-bearing sedimentary rocks, while in situ and bulk S isotopic compositions (δ34SPy+Sp = +20.06 to +23.86‰; δ34SGn = +17.26 to +18.44‰) of sulfides exhibit high consistency with those of sulfates (δ34SBrt = +17.01 to +19.07‰) within the ore-bearing strata. This suggests that the majority of metallogenic materials and reduced sulfur originated from this source. Meanwhile, the S-Pb isotopic data and relatively high ore-forming temperature (206 ℃) further reveal that the ore-bearing fluids underwent gradual migrated and evolved from the basement to the ore-hosting strata. The Emeishan magmatism not only provided the majority of the thermal power for the fluid circulation, but also contributed a portion of the ore-forming fluids and materials. During the late Triassic, ore-forming fluids migrated along compresso-shear reverse faults to coeval secondary extensional ore-hosting structures due to regional compressive tectonic stresses caused by the Indosinian orogeny and Xuefengshan intraplate orogeny. The mixing of metal-rich hydrothermal fluids with the marine evaporites (mainly gypsum) within sedimentary rocks first triggered thermos-chemical sulfate reduction (TSR) process. The subsequent continuous W/R interaction resulted in a decrease in fluid acidity and temperature, ultimately leading to the precipitation of metal sulfides.

Thalictrum minutiflorum (Ranunculaceae), described from Guizhou province, China, is merged with T. ramosum

Based on critical observations on herbarium specimens (including type material) and living plants in the wild, we demonstrate that Thalictrum minutiflorum, described from Dejiang county in Guizhou province, China, is conspecific with T. ramosum, a species widely distributed in China’s Chongqing, northwestern Guangxi, Guizhou, western Hubei, western Hunan, central and southwestern Sichuan and northeastern Yunnan. We therefore reduce T. minutiflorum to the synonymy of T. ramosum herein. The description of hairiness is added for T. ramosum, which has been previously described as glabrous throughout. Mistakes in the documentation of collection information including collection localities and collection number of T. ramosum are corrected. Previous misidentifications of specimens of T. ramosum and the resultant wrong records of geographical distribution of this species are also corrected.

Metallogenesis and Formation of the Maliping Pb-Zn Deposit in Northeastern Yunnan: Constraints from H-O Isotopes, Fluid Inclusions, and Trace Elements

The Maliping large-scale Pb-Zn deposit is located in the Sichuan-Yunnan-Guizhou Pb-Zn polymetallic metallogenic triangle area (SYGT), where the Pb-Zn ore body is hosted in the interlayer fracture zone at the interface between siliceous cataclastic dolomite and clastic rocks in the Lower Cambrian Yuhuchun Formation and is tectonically driven. Unlike other Pb-Zn de-posits hosted in the Sinian and Carboniferous carbonate rocks in the area, the metallogenic mechanism and deep and peripheral ore prospecting prediction research require further exploration. In this study, representative samples of a typical orebody profile were systematically collected, and microthermometry of fluid inclusions and H-O isotopes and metal sulfide trace element analyses were performed. The main findings were as follows: (1) The fluid inclusion study showed that the ore-forming fluids have vapor-rich phase reduction characteristics of medium-low temperature, salinity, and density. (2) H-O isotopic studies showed that the ore-forming fluids are derived from the mixing of deep-source fluids flowing through the deep fold basement (Kunyang Group) and or-ganic-containing basin brine. (3) Rare earth element (REE) characteristics indicate that the ore-forming materials were primarily derived from the folded basement (Kunyang Group). (4) The trace element study showed that sphalerite is relatively enriched in Cu, Cd, Ga, and Ge, while depleted in Fe, Mn, Sn, and Co, similar to the typical Huize-type (HZT) Pb-Zn deposit in the area. Therefore, it is suitable to explore the deposit using a large-scale “four step style” ore prospecting method for ore prospecting and prediction. Moreover, the results provide a reference for the study of Pb-Zn metallogenic systems and new ideas for the deep and peripheral prospecting of Pb-Zn deposits in this area.

Thermodynamic Calculations of Direct Reduction Smelting Technology of Copper Oxide Ores Based on Smelting Slag from the Yubeidi Site, Yunnan Province

The current research on metallurgical remains from scientific excavations in northeast Yunnan from the Bronze Age period is insufficient. In order to study the smelting technology of the Bronze Age in north-eastern Yunnan, samples of slag and mineral excavated from the Yubei Di site in Dongchuan were examined. Based on the outcome of the characterization analysis, a simulation was executed utilizing the software Factsage 7.1 in order to generate a phase diagram that accurately portrays the melting procedure. This simulation aimed to produce the most credible representation of the phase transition by employing computational methods. Characterisation methods included Metallographic Microscopy, Scanning Electron Microscopy Energy Dispersive Spectromicropy (SEM-EDS), X-ray diffraction (XRD), and Radiocarbon Date (14C dating). The results showed that there was much copper ore left in the slag of the site. Most of these copper ores were in the form of copper ferrite or cuprous oxide. The copper ore was copper oxide ore, and metal copper particles appeared in a small amount of the slag. Most of the slags unearthed from the site of the Yubeidi site were products of sulfur-containing oxide reduction and smelting into copper. Based on the outcomes of the simulations, it was established that the slag excavated from the Yubeidi site was mainly from the reduction and smelting process of sulphur-containing copper oxide minerals into copper, without consciously adding fluxes, not having mastered the slag-making techniques for different types of copper ores, and with primitive techniques. The carbon 14 dating results show that the age of the slag was during the Spring and Autumn Period and the Warring States Period.

Analysis of Qiaojia earthquake disasters in the Zhaotong area: Reasons for “small earthquakes and major disasters”

In May 2020, a magnitude 5.0 earthquake occurred in Qiaojia County, Yunnan. This earthquake was characteristics of relatively common “small earthquakes and major disasters” in the Zhaotong area of northeastern Yunnan. Yunnan province is an area in China with a high incidence of moderately strong earthquakes with magnitude 5 or above. In this region, the unique geological structure background and geographical environment of the Zhaotong area make it the most severely damaged area not only in Yunnan but also in all of China. The geological structure of the Zhaotong area is complex, and the neotectonic movements are strong. Based on the disasters of 8 moderate and strong earthquakes in Zhaotong since 2000, this paper analyses the causes of the “small earthquakes and major disasters” in Zhaotong city and provides suggestions for disaster reduction and emergency response after an earthquake.

Ghosts in the shell: The promises of water users' associations and the double life of Elinor Ostrom's design principles in rural China

Water is a matter of great concern for the PRC, especially for its agricultural sector, besieged by shortage, soil degradation, and raising production costs. Because of this, Water Users' Associations (WUA) are garnering domestic attention as a cost-effective solution for growth-compatible sustainability. These associations are inspired by Elinor Ostrom's design principles for the management of common resources. Through long-term ethnography among various stakeholders of the Yunnanese water sector, this article challenges the notion that the implementation of Ostrom-inspired WUAs in the Chinese countryside is fulfilling the associations' accompanying promises of sustainable growth. Instead, this study finds that Chinese WUAs proliferate thanks to pre-existing promises of collective prosperity. North-eastern Yunnan is rich in social arrangements for sustainable water management that predate the introduction of WUAs and make their ordinary operations possible. WUAs proponents conveniently blame the failure they see in Ostrom-inspired organisations on said arrangements while retaining faith in Ostrom's design principles. An ethnography of Ostrom-inspired associations can salvage Ostrom's intellectual project from the prescriptive readings of development planners and her critics. Yet, it also shows that alternative sustainable arrangements in human projects for the environment may become less plausible once captured by the prescriptive episteme of development planners.