Western Yunnan Research Articles

A brief overview of the unearthed “Analects” documents in East Asia over the past 50 years

From the perspective of newly unearthed inscriptions of the “Analects” of Confucius in East Asia over the past 50 years, it can be seen that it is a “living” text (活体) or “hypertext” (超文体) that is constantly developing and changing in time and space, often filtered and reconstructed due to subjective and objective needs. By the middle of the Western Han Dynasty, the differentiation and standardization of the “Qi Analects” (齐论语), “Gu Analects” (古论语), and “Lu Analects” (鲁论语) had not been completed, indicating that the compilation of the “Analects” had not been finalized. With the expansion of the Han and Tang empires and external exchanges, the “Analects” had spread to regions such as the Western Regions, Xinjiang, and Yunnan, as well as the Korean Peninsula and the Japanese archipelago. This also marked the gradual formation and establishment of the East Asian Sinicized cultural sphere centered around Confucianism and its ideological concepts with the “Analects” as the core.

Characteristics and Formation Mechanism of Geothermal Resources in Tectonically Active Regions: A Case Study of the Red River Fault in Western Yunnan Province, China

Characteristics and Formation Mechanism of Geothermal Resources in Tectonically Active Regions: A Case Study of the Red River Fault in Western Yunnan Province, China

Constraints of in-situ elemental compositions and U–Pb ages of cassiterite on the origin of the Cretaceous Gejiu and Dulong tin deposits, SW China: Implications for the linkage of tin belts in SE Asia

The western Yunnan tin belts in SW China and the southern Myanmar tin belt in SE Asia are traditionally thought to be part of the SE Asian tin metallogenic province. However, the tectonic setting of the Youjiang tin belt in SW China and its genetic relationship to the other tin belts are poorly documented. In this belt, the giant Gejiu and Dulong tin deposits are typical of skarn-type deposits and both contain contact and distal skarn orebodies. Tin ores of distal orebodies in these two deposits are composed of cassiterite, sulfide and calcite. In both deposits, most cassiterite grains from these ores are rich in Fe and W and depleted in Nb and Ta. They have 238U/206Pb ages between 81.4 and 84.1 Ma, similar to hosting granitic plutons. Two generations of cassiterite with distinctly different microtextures and trace elemental compositions can be recognized. The first generation (Cst-I) is compositionally and texturally homogeneous, but the second generation (Cst-II) displays distinctly oscillatory zoning. Cst-II contains Nb, W, and U lower, and Fe, Ta, Zr and chalcophile elements (Ga, Ge, In, and Sb) higher than Cst-I. These textural and compositional variations reflect the potential involvement of meteoric water in the magmatic-hydrothermal system. In this system, ore-forming fluids were evolved to more alkaline and oxidized to facilitate the precipitation of cassiterite. Our study indicates that these two deposits in the Youjiang tin belt have mineralization styles similar to those in the adjacent western Yunnan and southern Myanmar tin belts and all these tin belts belong to the SE Asian metallogenic provinces. A westward-younging trend of tin mineralization in these three belts can be explained by the rollback of the subducted Neo-Tethyan oceanic slab. This setting is different from the one related to the subduction of the Paleo-Pacific plate.

Spatio-temporal evolution of the Paleo-Tethys in western Yunnan: Insights from mafic rocks in the Lancang tectonic belt

The Sanjiang orogenic belt in the southeastern Tibetan Plateau provides an excellent record of the Paleo-Tethys tectonic evolution. This study introduces new constraints on the spatio-temporal evolution of the Paleo-Tethys through zircon UPb ages, in-situ LuHf isotope data, and analyses of whole-rock major oxides, trace elements, and Sr-Nd-Pb isotopic compositions from Late Paleozoic mafic rocks in the Lancang tectonic belt. The mafic rocks from the Xiaoheijiang, Banpo, and Yakou areas were dated to approximately 281–267 Ma, 295–292 Ma, and 293–291 Ma, respectively. The Xiaoheijiang mafic rocks exhibit geochemical signatures resembling those of fore-arc basalt, characterized by low (La/Sm)N, relatively flat rare earth element (REE)-normalized patterns, positive εNd(t) (+5.6 to +10.1), and zircon in-situ εHf(t) values (+10.0 to +14.9). These features indicate an origin from a depleted mantle source with minor contributions from slab-derived components. The Banpo and Yakou mafic rocks display geochemical affinities to back-arc basin basalt, similar to the Okinawa Trough back-arc basin basalt. Their εNd(t) values range from +5.6 to +9.9 and εHf(t) values from +9.5 to +15.0, suggesting derivation from a mantle wedge source modified by slab-derived fluids or melts. In combination with available geochronological data concerning the Paleo-Tethys evolution along the Lancang tectonic belt, our findings support the hypothesis that the slow-speed, low-angle subduction of the Paleo-Tethys Ocean led to the formation of a forearc accretionary complex. The slab-derived fluids metasomatized the mantle wedge as subduction depth and angle increased, facilitating the development of the Lincang arc magmatism and the opening of the Banpo-Yakou back-arc basin. Continuous subduction promoted slab retreat under gravitational forces, inducing the upwelling of depleted mantle and the forming of forearc magmas.

Correction to: Cassiterite geochronology and geochemistry of the Yunling Sn deposit: implication for late Cenozoic mineralization in western Yunnan, China

Correction to: Cassiterite geochronology and geochemistry of the Yunling Sn deposit: implication for late Cenozoic mineralization in western Yunnan, China

The complete chloroplast genome and phylogenetic analysis of Garcinia esculenta Y. H. Li. 1981 (Clusiaceae)

Garcinia esculenta Y. H. Li. 1981 (Clusiaceae) is an endemic tree species in China, primarily found in western and northwestern Yunnan Province. In this research, the complete chloroplast genome of G. esculenta was sequenced using the Illumina NovaSeq6000 platform. The result showed that the length of the complete chloroplast genome was 155,853 bp, which was composed of a large single-copy region (LSC) of 84,534 bp, a small single-copy region (SSC) of 17,175 bp, and a pair of inverted repeat (IR) regions of 27,072 bp. The overall GC content was 36.1%. The complete chloroplast genome encompassed 128 genes, comprising 83 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Phylogenetic analysis of the complete chloroplast genome sequences of 22 species revealed that G. esculenta is most closely related to G. oblongifolia.

New Ordovician bivalves from the Indochina Palaeoplate in Dali, western Yunnan, Southwest China and their palaeogeographic significance

A centre of radiation for Ordovician bivalves is identified based on an abundant and diverse fauna from the Hsiangyang Formation (Darriwilian, Middle Ordovician) of Dali, western Yunnan, Southwest China. It consists of 22 species of 18 genera including 1) one new genus and four new species: Rhomboconcha tresdentes n. gen. n. sp., Fasciculodonta curvata n. sp., Glyptarca symmetrica n. sp., and Paracyclas initium n. sp.; 2) three taxa known from elsewhere but initially found in Dali: Praeleda sp., Glyptarca sp., and Redonia deshayesi; 3) other taxa previously reported by Fang and Cope (2004). Numerical analysis of the distribution of 11 Middle Ordovician bivalve faunas from different regions shows two distinct faunal groups, the HPL group, representing the bivalves that lived in higher palaeolatitudes, and the LPL group (including Australia and South China) in lower palaeolatitudes. The bivalve fauna from Dali correlates with both groups, indicating that the Indochina Palaeoplate was located between these two groups, and in middle–high palaeolatitudes. Thus, the Indochina Palaeoplate was probably an isolated centre for bivalve radiation during the Middle Ordovician; those genera confined to Dali did not then spread to other palaeoplates.

Predicting the potential geographical distribution of Zingiber striolatum Diels (Zingiberaceae), a medicine food homology plant in China.

Zingiber striolatum Diels is a unique medicine food homology plant native to China. In recent years, due to severe habitat destruction, studying the impact of climate change on the distribution of wild resources is of great significance for the ecological conservation and artificial cultivation of Z. striolatum. This study collected 141 valid species distribution records, and 37 environmental variables, and projected two future climate scenarios (SSP126 and SSP585) for two periods (2050s and 2090s). By employing Pearson analysis, Maximum Entropy Model (MaxEnt), and Geographic Information System (ArcGIS), we predicted the potential suitable habitats for Z. striolatum under present and future climates, as well as identified the dominant environmental variables influencing its distribution. The results indicated that the MaxEnt model performed well (AUC > 0.9) with high accuracy and reliability. The dominant environmental factors included Precipitation of driest quarter (39.0 ~ 473.8mm), Precipitation of wettest quarter (593.2 ~ 1269.4mm), Temperature annual range (9.8 ~ 28.6℃), and Mean diurnal range (6.5 ~ 9.6℃). The highly suitable areas for Z. striolatum were mainly distributed in western and southern Yunnan, northern and western Guangxi, Guangdong, Fujian, and central Hainan. Under future climate change, the centroid of the total suitable area for Z. striolatum is projected to shift towards the southwest (Yungui Plateau) at higher elevations.

Tsuga leaves from the Neogene Baoshan Basin in southwest China and their palaeoecological implications

Tsuga (Endl.) Carrière (Pinaceae) has a rich fossil record represented by pollen, leaves, wood and seed cones. Although fossil leaves of the genus have been widely documented, most of them have not been examined microscopically, which may limit their taxonomic resolution. In this study, three-dimensionally preserved leaves and leaf fragments of Tsuga from the Neogene (latest Miocene to Pliocene) Baoshan Basin in western Yunnan, southwest China, were examined both morphologically and micromorphologically. The fossil leaves are characterized by flattened and bifacial shape, round to obtuse apex and petiolate base, adaxially sunken and abaxially elevated midvein, adaxial surface without stomata and with elongated, smooth-margined epidermal cells, and abaxial surface with two stomatal bands along the midvein, each stomatal band consisting of 6–8 longitudinal stomatal lines. Based on comparisons with extant species of the genus, we found that the fossil leaves show the closest affinity to Tsuga dumosa (D. Don) Eichler, an extant species growing in the modern western Yunnan. As modern species of Tsuga prefer humid conditions, our fossil find suggests a humid climate in the Baoshan Basin at the time of fossil deposition, probably due to the influence of the Indian summer monsoon from the southwest. This is consistent with previous results of quantitative palaeoclimate reconstructions using spore/pollen fossil assemblages. Our study provides new fossil evidence for the origin of modern conifer diversity in southwest China. It highlights the importance of microscopic studies in the taxonomic resolution of fossil leaves of Pinaceae.

Investigation of the 2011 Yingjiang, Yunnan, China Ms. 5.8 Earthquake Sequence: Seismic Migration, Seismogenic Mechanism, and Hazard Implication

On March 10, 2011, an Ms. 5.8 earthquake struck Yingjiang City, western Yunnan, China, causing destructive damage. Due to the very sparse distribution of seismic stations on the southwestern border of China, its seismogenic structure and mechanism remain controversial. In this study, with the aid of machine-learning-based detection and location workflow and template matching technique, we detect 10,356 events ranging from December 1, 2010, to April 30, 2011. The high-precision earthquake catalog shows that the foreshocks initiated in the extensional stepover connecting the northeast and middle segments of the Dayingjiang fault and then bilaterally extended northeast and southwest, with migration fronts that can be simulated by fluid diffusion model with diffusivities of 0.8 m2/s and 0.19 m2/s, respectively. The mainshock occurred at the southwest end of the foreshock sequence and then probably activated the northwest-trending blind fault. In addition, we determine the full moment tensor solutions for the mainshock, six large foreshocks, and one aftershock, with magnitudes ranging from 3.03 to 5.80, in which the mainshock was characterized by an obvious negative isotropic (ISO) component. The static Coulomb failure stress change caused by five Mw ≥ 4.0 foreshocks on the mainshock fault plane is ∼24 kPa, reaching the typical static triggering threshold. Therefore, we suggest that both the fluid diffusion and stress perturbation contribute to triggering the mainshock. This study advances our understanding of the spatiotemporal evolution, seismogenic mechanism, and hazard implication for the Yingjiang Ms. 5.8 earthquake and provides additional evidence of natural fluid-triggered seismicity in western Yunnan.

Fine Shallow Structures of Binchuan Basin Inverted From Receiver Functions and Implications for Basin Evolution

AbstractThe understanding of the velocity structure and basement morphology within the basin is crucial for seismic hazard mitigation and the study of basin evolution. To explore the intricate structure of the Binchuan Basin in western Yunnan, China, we deployed a linear dense array in the northern region of the Binchuan Basin, with inter‐station distance ranging from 50 to 100 m. We propose a novel receiver function processing workflow. Initially, we extracted coherent receiver functions based on the dense array, followed by a inversion of basement morphology, S‐wave velocities, and sedimentary layer's average Vp/Vs ratio jointly with frequency‐dependent teleseismic apparent shear velocity and receiver function waveforms. The results show that S‐wave velocity anomalies correspond to the unconsolidated sediments. The thickness of the sedimentary layer ranges from ∼0.5 to ∼0.75 km. The basement morphology suggests the basin is controlled by normal faults. Additionally, intra‐basin faults displayed higher fault displacement to length ratios (∼0.27) than most isolated normal faults (10−3–10−1), which may result from accumulated fault displacement due to interactions between fault segments. These results emphasize the significant role of N–S trending intra‐basin faults in basin evolution, suggesting that micro‐block rotations and transitional movements within the Northwestern Yunnan Rift Zone are primary mechanisms shaping the Binchuan Basin. We further proposed a multi‐stage model for the evolution of the Binchuan Basin. The robustness testing validates that the proposed processing flow is an effective approach to comprehensively image the basin velocity structure and the basement morphology.

Full Waveform Inversion Based on Dynamic Time Warping and Application to Reveal the Crustal Structure of Western Yunnan, Southwest China

Full Waveform Inversion Based on Dynamic Time Warping and Application to Reveal the Crustal Structure of Western Yunnan, Southwest China

Cassiterite geochronology and geochemistry of the Yunling Sn deposit: implication for late Cenozoic mineralization in western Yunnan, China

Cassiterite geochronology and geochemistry of the Yunling Sn deposit: implication for late Cenozoic mineralization in western Yunnan, China

Microstructures, Deformation Mechanisms and Seismic Properties of Synkinematic Migmatite from Southeastern Tibet: Insights from the Migmatitic Core of the Ailao Shan-Red River Shear Zone, Western Yunnan, China

Microstructures, Deformation Mechanisms and Seismic Properties of Synkinematic Migmatite from Southeastern Tibet: Insights from the Migmatitic Core of the Ailao Shan-Red River Shear Zone, Western Yunnan, China

Jurassic tectonic regime transition of the southwestern Yangtze Block, SW China: evidence from sedimentary provenance analysis

The Lufeng Basin (LFB) in central Yunnan is located on the southwestern margin of the Yangtze Block in the eastern segment of the Tethys tectonic domain, where the Paleo-Tethys and the Paleo-Pacific tectonic domains converge. Jurassic red beds in this basin record the closure of the Paleo-Tethys Ocean and key information of the tectonic transition driven by the spreading of the Paleo-Pacific plate. We present sedimentary provenance analysis on these Jurassic red beds based on heavy mineral assemblages and detrital zircon geochronology. The results indicate that the strata in this basin were deposited after 214 Ma, and the Early Jurassic Lufeng Formation (Lufeng Fm.) mainly sourced from the west of the LFB with minor contributions from the western Yunnan. In contrast, the sedimentary provenance of the Middle Jurassic Chuanjie Formation (Chuanjie Fm.) and Laoluocun Formation (Laoluocun Fm.) shifted to the proximal ancient basement surrounding the basin and the east of the LFB. The regional unconformity between the Early and the Middle Jurassic may have resulted from the subduction of the Paleo-Pacific plate, jointly influenced by two tectonic domains. The sedimentary provenance shift in the Middle Jurassic may be related to the local uplift of the southwestern Yangtze Block caused by the subduction of the Paleo-Pacific plate. The tectonic regime transition associated with this highest peak of local uplift occurred at ∼170 Ma.

Modern Lacustrine Phytoliths and their Relationships with Vegetation and Climate in Western Yunnan, SW China

Modern Lacustrine Phytoliths and their Relationships with Vegetation and Climate in Western Yunnan, SW China

Geographical pattern of the deviation between taxonomic, phylogenetic, and functional diversity and its implications for the conservation of Chinese orchids

Orchidaceae stands as one of the “flagship” groups in global biodiversity conservation, attracting significant attention from researchers in China. Previous studies have focused on taxonomic diversity, neglecting the integration of phylogeny and functional aspects. Here, we have leveraged a large dataset of distributions, evolutionary relationships, and functional traits of orchids in China to analyze geographic patterns of species richness (SR), weighted endemism (WE), phylogenetic diversity (PD), phylogenetic endemism (PE), functional diversity (FD), and functional endemism (FE). Furthermore, we analyzed the deviations between PD (or FD) and SR (PDdev, and FDdev), as well as between PE (or FE) and WE (PEdev, and FEdev), taking into account climatic and environmental variables. We also delineated the priority protection and survey areas of orchid plants in China. Our results revealed that the geographic patterns of SR, WE, PD, PE, FD, and FE for orchids generally exhibited similar trends. However, there were notable inconsistencies in the geographical patterns of PDdev, FDdev, PEdev, and FEdev, which might be related to the different environmental responses of these four diversity deviation metrics. We have pinpointed six priority conservation areas for orchids in China, i.e., southeasterrn Xizang, western Yunnan, central Yunan, the Karst area at the border of Guizhou and Guangxi, the border of Guangdong and Guangxi, and Taiwan Island. In addition, we have also identified certain priority survey areas for orchids, encompassing southeastern Xizang and other crucial locales. These findings will guide future conservation and research efforts aimed at safeguarding the rich biodiversity of orchids in China.

Recognition of Neogene tin mineralization in the Southeast Asian tin belt

The Southeast (SE) Asian tin belt is a major tin producer globally, with a prolonged mineralization history from the Permian to Paleogene (ca. 285−45 Ma). Tin deposits in this region are typically associated with tectonic settings that involve subduction and collision of the Paleo-, Meso-, and Neo-Tethys slabs. Ca. 40 Ma, a notable transition occurred in the tectonic regime of SE Tibet, with the Neo-Tethys subduction giving way to lateral extrusion of the Indochina block along major strike-slip faults. Previously, it was believed that this shift had brought tin mineralization to a halt. In this study, we present in situ laser ablation−inductively coupled plasma−mass spectrometry U-Pb cassiterite ages of 21−19 Ma from the Yunling tin deposit located in western Yunnan, China. Yunling produces gem-quality cassiterite that is transparent but contains low U contents, which renders usual U-Pb dating techniques unusable. To address this, a customized dating protocol involving cathodoluminescence (CL) imaging and testing of U distribution on crystallographically well-defined cassiterite crystals was applied. The study revealed two types of primary microstructures in cassiterite: volumetrically dominant concentric oscillatory growth zones and subordinate CL-dark sector zones. The U content shows a preferential enrichment in the CL-dark sector zones, typically tens of parts per million (ppm), which is two orders of magnitude greater than the U content in the concentric zone. This is significant, as the dating results (21−19 Ma) obtained through the targeted selection of CL-dark sector zones represent the youngest tin mineralization event in the SE Asian tin belt. Additionally, these results challenge the established belief that the ore-hosting Indosinian granite, dated to ca. 215 Ma, was related to Sn mineralization in the Yunling area. We suggest that emplacement of the early Neogene Sn mineralization at Yunling may be genetically connected to extensive delamination of the lithosphere in southeastern Tibet. The lithospheric delamination led to the upwelling and decompression partial melting of the asthenosphere, which provides a plausible explanation for the high temperature required for the release of Sn from biotite-dehydration melting of sedimentary protolith. The study also highlights the potential of Oligocene−Miocene-aged granites situated in the Sanjiang Tethys and adjacent areas of western Yunnan as prospective exploration targets for tin mineralization.

Research on Territorial Spatial Development Non-Equilibrium and Temporal–Spatial Patterns from a Conjugate Perspective: Evidence from Chinese Provincial Panel Data

Clarifying the intrinsic nature and formation mechanisms of the territorial spatial development non-equilibrium, optimizing the allocation of territorial resources, promoting regional balanced development, and alleviating regional development disparities have become common endeavors of all countries seeking to enhance development quality. This study, based on the land use and socio-economic data of 31 provinces and cities in China from 2006 to 2020, utilized the kernel density estimation method and ArcGIS spatial analysis to explore the spatiotemporal evolution characteristics of China’s territorial spatial development non-equilibrium. The research findings are as follows: (1) From 2006 to 2020, both the land development intensity and land supply capacity showed an increasing trend, with increases of 21.4% and 8.03%, respectively. However, their spatiotemporal evolutions significantly differed. (2) The state of the territorial spatial development non-equilibrium in China significantly improved, with a rising trend in the territorial spatial equilibrium degree. Regional disparities in the territorial spatial equilibrium degree decreased. The number of provinces and cities in a state of underdevelopment decreased from 23 to 8, while the number in an equilibrium state increased from 7 to 21. The central and western regions showed more significant improvements in the territorial spatial equilibrium degree and a greater reduction in regional disparity when compared to the eastern and northeastern regions. (3) China exhibited distinct regional disparities in the territorial spatial equilibrium degree. The overdeveloped areas were Beijing and Shanghai. The underdeveloped regions were primarily concentrated in western areas, including Sichuan, Yunnan, and Xinjiang. The high-level equilibrium regions were predominantly located in the southeastern coastal provinces and the central plains region, while the low-level equilibrium regions included Inner Mongolia, Ningxia, Qinghai, and the three northeastern provinces. (4) From the perspective of the number of agglomeration types, the order is HH (high–high) > LH (low–high) > LL (low–low) > HL (high–low), and China’s TSED exhibits a spatial proximity peer effect. The innovation of this study consists of the following aspects: (1) The clarification of the fact that the essence of equilibrium does not require an exact 1:1 match, as with “two horses”; rather, it entails the maintenance of a slight surplus of land supply capacity over land development intensity. This approach allows the possibility of future sustainable development by leaving room for expansion. (2) The differentiation between high-intensity conjugation (in terms of both quantity and quality) and low-intensity conjugation (quantity only) from a conjugate perspective. This categorization aids in a more comprehensive and in-depth understanding of the territorial spatial development non-equilibrium and its spatiotemporal patterns. It provides crucial information for the formulation of sustainable national territorial development plans and the promotion of a regional development equilibrium.

Geochemical and PGE compositional characteristics of the serpentinite in the Laowangzhai gold deposit of the Western Yunnan: Implications for the Paleo-Tethyan Ocean evolution

Geochemical and PGE compositional characteristics of the serpentinite in the Laowangzhai gold deposit of the Western Yunnan: Implications for the Paleo-Tethyan Ocean evolution