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This paper explores a previously unrecorded style of East-West architectural ornamentation in Tengchong, Yunnan Province, China, overlooked in historical architectural studies. The aim of this research is to both document and analyze this unique blend of Eastern and Western architectural elements, employing both qualitative and quantitative methods. Initially, literary research identifies relevant sites, which are subsequently examined through field research to collect firsthand data on the local architectural decorations that exhibit this East-West synthesis. Employing an interdisciplinary approach that integrates concepts from biology and statistics, the study views these architectural decorations as a living organism. This perspective allows for a detailed examination of how different cultural elements are incorporated into local architecture, analyzed quantitatively and statistically. Through this research, a qualitative description of these hybrid architectural elements is developed, further enriched by a quantitative analysis based on statistical methods. The qualitative aspect of the study traces the historical evolution of this East-West architectural form, observing changes in themes and structures. In terms of quantitative findings, a detailed statistical profile of these local architectural features is established, which supports the qualitative insights. Overall, this research sheds light on a neglected aspect of architectural ornamentation, presenting a thorough analysis of its development and current state through an innovative mix of qualitative and quantitative research techniques. This study not only provides new data but also opens up fresh avenues for future research on similar topics.

The formation of highly evolved, dacitic magmas has been attributed to various processes, including crystal fractionation, partial melting of overlying crust, and/or assimilation of crustal material into an evolving magma chamber. These processes are undoubtedly primary processes involved in the formation of dacites, but they may not be the only mechanism involved in the formation of high-silica dacites. For instance, mafic magma replenishment has been proposed as an additional mechanism but has not been assessed, and thus, its role has not been well-constrained. The Daliuchong volcano is the result of one of the largest eruptive events within the Tengchong Volcanic Field (TVF) in southwest China during the Early-Middle Pleistocene. Here, we conducted detailed mineral textures, mineral chemistry, and geochemical studies on Daliuchong pyroclastic rocks to explore the pre-eruptive storage conditions and evolution processes of the magma. The Daliuchong pyroclastic rocks are dacitic in composition. The samples show porphyritic textures characterized by phenocrysts of plagioclase, amphibole, clinopyroxene, orthopyroxene, and Fe-Ti oxides. Additionally, two distinct types of glomerocryst are identified: a gabbroic glomerocryst containing plagioclase + clinopyroxene + orthopyroxene ± Fe-Ti oxides assemblage and a dioritic glomerocryst containing plagioclase + amphibole ± pyroxene ± Fe-Ti oxides assemblage. Both phenocryst and glomerocryst show rich micro-textures. The Daliuchong dacite exhibits bulk compositional heterogeneity. Analysis of bulk-rock data suggests that this heterogeneity may arise from both the differentiation of the dacite itself and the injection of mafic magma. The compositional similarity between the Daliuchong dacite and experimentally produced partial melts of metamorphic basalt supports that the Daliuchong dacite was predominantly formed through the partial melting of the mafic lower crust. Thermobarometry estimation indicates that clinopyroxenes with high Mg# crystallized at 560-870 MPa, whereas amphibole and clinopyroxenes with low Mg# crystallized at 185-300 MPa. Based on the observed phase relations and the calculated crystallization conditions, we propose that during the differentiation of the Daliuchong dacite, heterogeneous dacitic magma formed by partial melting accumulated in a deep magma reservoir (21-32 km) before subsequently ascending toward shallower depths. Crystallization of plagioclase, amphibole, Fe-Ti oxides, and small amounts of pyroxene and apatite occurred at a shallower depth (7-10 km). The presence of coarse-sieve texture, fine-sieve texture, and oscillatory zoning with high amplitude in plagioclase suggests intermittent injection of mafic magma into the shallow magma reservoir, with the eruption of dacitic magma occurring after the final mafic magma replenishment. The petrological evidence above advocates that primitive magma replenishment could have been involved in the formation and triggered the eruption of dacite in the Daliuchong volcano. [ABSTRACT FROM AUTHOR]

Ascertaining regional radiogeochemical characteristics and lithospheric thermal structure characteristics is paramount for identifying the resource potential of hot dry rocks. This study conducted thermal conductivity testing and whole-rock analyses of outcrop granites of different formation epochs from the Tengchong area. Moreover, combined with the previously published whole-rock data and the data related to radioactive heat production rates, this study conducted geological, geophysical and geothermal analyses. Key findings are: (1) Granites in the Tengchong area exhibit an average radioactive heat generation rate of 5.54 μ W m−3. Among them, the Late Cretaceous granites have an average radioactive heat generation rate of 8.08 μ W m−3, suggesting high heat production granites. (2) Granites in the Tengchong area present an average thermal conductivity of 3.135 W.m−1K−1, relatively akin to the average values of granitic rocks worldwide. Compared to granites of other epochs, the Late Cretaceous granites manifest significantly higher thermal conductivities, with an average of 3.28 W.m−1K−1. (3) There is a negative correlation between the mica content and the thermal conductivity of the granites in the Tengchong area. (4) The Tengchong area holds potential for hot dry rocks exploitation and is inferred to have a lithospheric structure characterized by hot mantle and cold crust. [ABSTRACT FROM AUTHOR]

The formation of highly evolved, dacitic magmas has been attributed to various processes, including crystal fractionation, partial melting of overlying crust, and/or assimilation of crustal material into an evolving magma chamber. These processes are undoubtedly primary processes involved in the formation of dacites, but they may not be the only mechanism involved in the formation of high-silica dacites. For instance, mafic magma replenishment has been proposed as an additional mechanism but has not been assessed, and thus, its role has not been well-constrained. The Daliuchong volcano is the result of one of the largest eruptive events within the Tengchong Volcanic Field (TVF) in southwest China during the Early-Middle Pleistocene. Here, we conducted detailed mineral textures, mineral chemistry, and geochemical studies on Daliuchong pyroclastic rocks to explore the pre-eruptive storage conditions and evolution processes of the magma. The Daliuchong pyroclastic rocks are dacitic in composition. The samples show porphyritic textures characterized by phenocrysts of plagioclase, amphibole, clinopyroxene, orthopyroxene, and Fe-Ti oxides. Additionally, two distinct types of glomerocryst are identified: a gabbroic glomerocryst containing plagioclase + clinopyroxene + orthopyroxene ± Fe-Ti oxides assemblage and a dioritic glomerocryst containing plagioclase + amphibole ± pyroxene ± Fe-Ti oxides assemblage. Both phenocryst and glomerocryst show rich micro-textures. The Daliuchong dacite exhibits bulk compositional heterogeneity. Analysis of bulk-rock data suggests that this heterogeneity may arise from both the differentiation of the dacite itself and the injection of mafic magma. The compositional similarity between the Daliuchong dacite and experimentally produced partial melts of metamorphic basalt supports that the Daliuchong dacite was predominantly formed through the partial melting of the mafic lower crust. Thermobarometry estimation indicates that clinopyroxenes with high Mg# crystallized at 560–870 MPa, whereas amphibole and clinopyroxenes with low Mg# crystallized at 185–300 MPa. Based on the observed phase relations and the calculated crystallization conditions, we propose that during the differentiation of the Daliuchong dacite, heterogeneous dacitic magma formed by partial melting accumulated in a deep magma reservoir (21–32 km) before subsequently ascending toward shallower depths. Crystallization of plagioclase, amphibole, Fe-Ti oxides, and small amounts of pyroxene and apatite occurred at a shallower depth (7–10 km). The presence of coarse-sieve texture, fine-sieve texture, and oscillatory zoning with high amplitude in plagioclase suggests intermittent injection of mafic magma into the shallow magma reservoir, with the eruption of dacitic magma occurring after the final mafic magma replenishment. The petrological evidence above advocates that primitive magma replenishment could have been involved in the formation and triggered the eruption of dacite in the Daliuchong volcano.

Archaeal viruses are one of the most mysterious parts of the virosphere because of their diverse morphologies and unique genome contents. The crenarchaeal viruses are commonly found in high temperature and acidic hot springs, and the number of identified crenarchaeal viruses is being rapidly increased in recent two decades. Over fifty viruses infecting the members of the order Sulfolobales have been identified, most of which are from hot springs distributed in the United States, Russia, Iceland, Japan, and Italy. To further expand the reservoir of viruses infecting strains of Sulfolobaceae, we investigated virus diversity through cultivation-dependent approaches in hot springs in Tengchong, Yunnan, China. Eight different virus-like particles were detected in enrichment cultures, among which five new archaeal viruses were isolated and characterized. We showed that these viruses can infect acidophilic hyperthermophiles belonging to three different genera of the family Sulfolobaceae, namely, Saccharolobus, Sulfolobus, and Metallosphaera. We also compared the lipid compositions of the viral and cellular membranes and found that the lipid composition of some viral envelopes was very different from that of the host membrane. Collectively, our results showed that the Tengchong hot springs harbor highly diverse viruses, providing excellent models for archaeal virus-host studies. [ABSTRACT FROM AUTHOR]

The Miocene–Quaternary Tengchong volcanic field in SE Tibet was generated after the main stage of continental collision between India and Eurasia. Consensus on the origin of Tengchong volcanism has not yet been achieved. In this study, we analysed the He-Ar isotopic compositions of olivine and pyroxene phenocrysts, whole-rock major and trace elements and Sr-Nd-Pb isotopic compositions. The 3He/4He ratios range from 4.1 to 8.2 Ra (Ra = 1.4 × 10−6), overlapping the values of mid-ocean ridge basalt (7.0–9.0 Ra) and subcontinental lithospheric mantle (SCLM, 5.2–7.0 Ra). The low 3He/4He (< 7.0 Ra) basalts have high 87Sr/86Sr (average of 0.707928) and La/Yb (average of 22.0) ratios and low Nb/La (average of 0.36) ratios, whereas the high 3He/4He (> 7.0 Ra) basalts exhibit relatively low 87Sr/86Sr (average of 0.706708) and La/Yb (average of 17.0) ratios and relatively high Nb/La (average of 0.52) ratios. These observations indicate that the primitive magmas originated from a mixture of metasomatized SCLM and enriched asthenospheric mantle. The SCLM was likely metasomatized by the subducted Neo-Tethyan oceanic plate, while the asthenospheric mantle was enriched by the subducting Indian oceanic plate. The increasing trend of 3He/4He ratios and decreasing trend of 87Sr/86Sr ratios over time suggest that the contribution of the metasomatized SCLM decreased after the late Pleistocene relative to that of the enriched asthenosphere, reflecting progressive lithospheric extension and thinning. Our results reveal that magmatic He isotopes can be used to constrain deep dynamic processes. [ABSTRACT FROM AUTHOR]

The hydrothermal system plays a crucial role in material and energy cycling between the lithosphere and hydrosphere. In general, seafloor hydrothermal systems are one of important Mg sinks, but the situation may not be the same as it is in terrestrial hydrothermal systems. In addition, the behavior of Mg isotopes during hydrothermal circulation is still unclear. Thus, in this study, we determined the Mg isotopic compositions of the hydrothermal fluids discharged in the Tengchong region to understand better the fate of Mg in the continental hydrothermal system. The δ2H and δ18O values of the Tengchong hydrothermal fluids indicate that the recharge water sources are primary from meteoric water and influenced by the evaporation process. In contrast, the subduction–related volcanic water input is limited, except in for the Rehai area. The Mg in most of the samples is contributed by percolated meteoric water. The measured δ26Mg values range from –0.969 to 0.173‰, which are enriched in light Mg compared to the volcanic rocks of Tengchong. Combined with the precipitation dissolution of carbonate, we calculated the δ26Mg value for the endmember fluid before precipitation, which shows that the process of carbonate precipitation changes the Mg isotope of the fluid, substantially. The Shiqiang (SQ) vent is unique among all of the samples, characterized by an extremely a high δ26Mg value and Mg concentration, and it is estimated that it could have been mixed with an upper crustal material. This also reveals the diversity of the hydrothermal fluid material sources in the subduction zone. [ABSTRACT FROM AUTHOR]

For the continental rift‐related geothermal system, the hydrothermal alteration zones are rarely studied for uranium exploration. High uranium concentrations (up to 36 ppm) are shown in the altered sandstones at the Rehai geothermal field (RHGF) in Tengchong, China. To demonstrate the uranium enrichment mechanism, this study comparatively examines the trace element (uranium in particular) and rare earth element (REE + Y) concentrations of hot spring water, spring deposits (sinters and sulphates), and altered host sandstones from the RHGF of the Tengchong volcanic area. Along the central north‐south trending fault at Rehai, sinters and sulphates are precipitated from hot spring water, and the Neogene sandstones have been altered by hydrothermal fluids into zones formed of various clay minerals. The δD and δ18O values for the hot spring water indicate that the geothermal water originates from meteoric water. The spring water and hot spring deposits have identical REE distribution patterns which are featured with heavy REE (HREE) enrichment and negative Eu anomalies. Among the hot spring deposits, the yellowish earthy aggregates (tamarugite) deposited at the acidic Zhenzhu Spring have the maximum U concentration (27 ppm). The altered sandstones at Rehai, however, display the highest U concentrations (14–36 ppm). The U enrichment in the hot spring deposits and altered host rocks at the Rehai geothermal field is probably related to the multiple cycles of uranium leaching from granites, transportation upward along fault structures by geothermal water, decompression, and fixation in the hot spring deposits and/or alteration products. The results indicate that alteration zones associated with geothermal systems are also potential targets for uranium exploration. [ABSTRACT FROM AUTHOR]

Terrestrial hot springs have been suggested to harbor diverse diazotrophic lineages by using DNA-based nifH gene phylogenetic analysis. However, only a small amount of diazotrophs were ever confirmed to perform nitrogen fixation. In order to explore the compositions of active diazotrophic populations in hot springs, the in situ expression and diversity of nifH and 16S rRNA genes were investigated in the sediments of hot springs (pH 4.3-9.1; temperature 34-84°C) in Tengchong, China, by using highthroughput sequencing. The results showed that active diazotrophs were diverse in the studied Tengchong hot springs. The main active diazotrophs in high-temperature hot springs were affiliated with Aquificae, while those in low-temperature hot springs belonged to Cyanobacteria and Nitrospirae. Such dominance of Aquificae and Nitrospirae of diazotrophs has not been reported in other ecosystems. This suggests that hot springs may harbor unique active diazotrophs in comparison with other type of ecosystems. Furthermore, there were significant differences in the phylogenetic lineages of diazotrophs between hot springs of Tengchong and other regions, indicating that diazotrophs have geographical distribution patterns. Statistical analysis suggests that the expression and distribution of nifH gene were influenced by temperature and concentrations of ammonia and sulfur seem in Tengchong hot springs. These findings avail us to understand element cycling mediated by diazotrophs in hot spring ecosystems. [ABSTRACT FROM AUTHOR]

A novel Gram-stain-negative, non-motile, short rod-shaped and aerobic bacterial strain, designated as CFH 74456 T, was isolated from sediment of a hot spring, Tengchong, Yunnan Province, south-western China. Growth occurred at 20–53 ºC (optimum 45 ºC), pH 7.0–9.0 (optimum pH 8.0) and up to 2.0% (w/v) NaCl (optimum 0–1.0%, w/v). The predominant respiratory quinone was ubiquinone 10 (Q-10). The major fatty acids (> 10%) were C17:1ω6c (17.9%) and summed feature 8 (38.6%). The polar lipid profile of strain CFH 74456 T was identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid, three unidentified glycolipids and three unidentified polar lipids. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain CFH 74456 T belongs to the genus Qipengyuania, and was most closely related to Qipengyuania sediminis CGMCC 1.12928 T (95.7%). The draft genome size of the isolate was 2.29 Mb with G + C content of 68.5%. The amino acid identity, average nucleotide identity and the digital DNA-DNA hybridization values between strain CFH 74456 T and the closest relatives ranged from 67.0 to 67.9%, 73.0 to 74.2% and 18.2–19.3%, respectively. On the basis of phenotypic, phylogenetic and genotypic analyses, it is concluded that strain CFH 74456 T represents a new species of the genus Qipengyuania, for which the name Qipengyuania thermophila sp. nov. is proposed. The type strain is CFH 74456 T (= KCTC 62921 T = CCTCC AB 2018237 T). [ABSTRACT FROM AUTHOR]

In Tengchong County, springs with wide physicochemical diversity provide a multitude of niches for extremophilic microorganisms. In this study, eight middle-low temperature spring sites along two continuous small streams with low water flow and slow speed in the fourth geothermal experience area of Rehai scenic spot were chosen, and geochemical characteristics and HTS of the 16S rRNA V4 region were used to analyze the prokaryotic community structure and diversity in the water and sediment of these sites. The effect of environmental factors on the microbial communities was explored via redundancy analysis (RDA). All sediment samples had higher alpha diversity values than the corresponding water samples. Twenty-five phyla were annotated; Euryarchaeota, Crenarchaeota, Aquificae, Thermotogae and Proteobacteria were the dominant phyla, accounting for 95.31% of all prokaryotes, with relative abundances above 5%. Aquificae dominated in water samples, while Euryarchaeota dominated in sediment samples. RDA indicated that temperature was the main factor influencing the microbial communities in the two streams. The study expands the current understanding of the microbiology of Tengchong hot springs and provides a basis for further mining of hot spring microbial and functional gene resources. [ABSTRACT FROM AUTHOR]

Abstract Background Mosquito-based arbovirus surveillance can serve as an early warning in evaluating the status of mosquito-borne virus prevalence and thus prevent local outbreaks. Although Tengchong County in Yunnan Province—which borders Myanmar—is abundant and diverse in mosquitoes, very few mosquito-based arbovirus investigations have been conducted in the recent decade. Herein, this study aims to evaluate the presence and the diffusion of mosquito-borne pathogens, currently prevalent in this region. Methods We collected 9486 mosquitoes, representing eight species, with Culex tritaeniorhynchus and Anopheles sinensis as the dominant species, during high mosquito activity seasons (July–October) in Tengchong, in 2018. Samples collected from 342 pools were tested using reverse-transcription PCR to determine the species, distribution, and infection rates of virus and parasite, and further analyze their genotypes, phylogenetic relationships, infection rate, and potential pathogenicity. Results Fifteen Japanese encephalitis virus (JEV) strains from Cx. tritaeniorhynchus pools were detected. Seven strains of insect-specific flaviviruses (ISFVs), including two Aedes flavivirus (AeFV) and Yunnan Culex flavivirus strains each, one Culex theileri flavivirus, Yamadai flavivirus (YDFV) and Anopheles-associated flavivirus (AAFV) strains each were detected in Aedes albopictus, Cx. tritaeniorhynchus, Cx. vagans, Cx. pseudovihnui, and An. sinensis pools, respectively. The whole-genome was successfully amplified in one strain of JEV and AeFV each. Phylogenetic analysis using the E gene placed all the newly detected JEV strains into the GI-b genotype. They showed highly nucleotide identities, and were most closely related to the strain detected in Tengchong in 2010. The comparison of the E protein of JEV strains and vaccine-derived strain, showed six amino residue differences. The bias-corrected maximum likelihood estimation values (and 95% confidence interval) for JEV in Cx. tritaeniorhynchus collected in Tengchong in 2018 were 2.4 (1.4–3.9). Conclusions A potential Japanese encephalitis epidemic focus with the abundance of host mosquitoes and high JEV infection rate was observed in Tengchong. In addition, at least five species of ISFVs co-circulate in this area. This study highlights the importance of widespread and sustained mosquito-based arbovirus surveillance in local areas to prevent the transmission of JEV, and other emerging/re-emerging mosquito-borne pathogens. Graphic Abstract

The hydrothermal system plays a crucial role in material and energy cycling between the lithosphere and hydrosphere. In general, seafloor hydrothermal systems are one of important Mg sinks, but the situation may not be the same as it is in terrestrial hydrothermal systems. In addition, the behavior of Mg isotopes during hydrothermal circulation is still unclear. Thus, in this study, we determined the Mg isotopic compositions of the hydrothermal fluids discharged in the Tengchong region to understand better the fate of Mg in the continental hydrothermal system. The δ2H and δ18O values of the Tengchong hydrothermal fluids indicate that the recharge water sources are primary from meteoric water and influenced by the evaporation process. In contrast, the subduction–related volcanic water input is limited, except in for the Rehai area. The Mg in most of the samples is contributed by percolated meteoric water. The measured δ26Mg values range from –0.969 to 0.173‰, which are enriched in light Mg compared to the volcanic rocks of Tengchong. Combined with the precipitation dissolution of carbonate, we calculated the δ26Mg value for the endmember fluid before precipitation, which shows that the process of carbonate precipitation changes the Mg isotope of the fluid, substantially. The Shiqiang (SQ) vent is unique among all of the samples, characterized by an extremely a high δ26Mg value and Mg concentration, and it is estimated that it could have been mixed with an upper crustal material. This also reveals the diversity of the hydrothermal fluid material sources in the subduction zone.

High-temperature SiO2-rich springs are one of the most indicative manifestations of deep geothermal activities. Although they often represent the valuable geothermal potentials and significances of the areas, their high SiO2 contents usually bring some non-negligible problems when we exploit the geothermal resources, especially the silica scales. To understand the sedimentation sequences of SiO2-rich hot springs and to expose its potential relationships with natural sinter deposits and silica scales in geothermal plants, this study make a couple of analyses of the water and solid samples collected from a natural SiO2-rich hot spring in Tengchong (i.e. Dagunguo spring) and isothermal evaporation experiments, including water chemistry analyses, X-ray diffraction, thin-section observation, and electron microscopy analyses. The modern sinters in Dagunguo spring are amorphous SiO2 which is largely formed of tight siliceous layers and some amorphous SiO2 spheres. Some silicified microorganisms, elemental sulfur, and clay are also found. The Dagunguo spring water is Na–Cl–HCO3-type SiO2-rich water, with a pH of about 8 and low dissolved concentrations of Al3+, Fe3+ and Mg2+. Isothermal evaporation (T = 84 °C) resulted in a sequence of precipitated minerals: amorphous SiO2 → halite → sodium sesquicarbonate dihydrate (trona) → potassium chloride (sylvine), accompanied by calcite, hydrous sodium sulfate (mirabilite) and sodium bicarbonate (baking soda). The amorphous SiO2 produced in the evaporation experiments exhibited different shapes and structures than the spherical opal-A formed by hot spring water precipitation under natural conditions. The study of precipitation sequence and minerals of hot spring water provides insight into the scaling mechanism of silica-rich geothermal water and anti-scaling measures that can be applied in the process of exploitation and utilization of geothermal resources. [ABSTRACT FROM AUTHOR]

In Tengchong County, springs with wide physicochemical diversity provide a multitude of niches for extremophilic microorganisms. In this study, eight middle-low temperature spring sites along two continuous small streams with low water flow and slow speed in the fourth geothermal experience area of Rehai scenic spot were chosen, and geochemical characteristics and HTS of the 16S rRNA V4 region were used to analyze the prokaryotic community structure and diversity in the water and sediment of these sites. The effect of environmental factors on the microbial communities was explored via redundancy analysis (RDA). All sediment samples had higher alpha diversity values than the corresponding water samples. Twenty-five phyla were annotated; Euryarchaeota, Crenarchaeota, Aquificae, Thermotogae and Proteobacteria were the dominant phyla, accounting for 95.31% of all prokaryotes, with relative abundances above 5%. Aquificae dominated in water samples, while Euryarchaeota dominated in sediment samples. RDA indicated that temperature was the main factor influencing the microbial communities in the two streams. The study expands the current understanding of the microbiology of Tengchong hot springs and provides a basis for further mining of hot spring microbial and functional gene resources.

Background: Mosquito-based arbovirus surveillance can serve as an early warning in evaluating the status of mosquito-borne virus prevalence and thus prevent local outbreaks. Although Tengchong County in Yunnan Province—which borders Myanmar—is abundant and diverse in mosquitoes, very few mosquito-based arbovirus investigations have been conducted in the recent decade. Herein, this study aims to evaluate the presence and the diffusion of mosquito-borne pathogens, currently prevalent in this region. Methods: We collected 9486 mosquitoes, representing eight species, with Culex tritaeniorhynchus and Anopheles sinensis as the dominant species, during high mosquito activity seasons (July–October) in Tengchong, in 2018. Samples collected from 342 pools were tested using reverse-transcription PCR to determine the species, distribution, and infection rates of virus and parasite, and further analyze their genotypes, phylogenetic relationships, infection rate, and potential pathogenicity. Results: Fifteen Japanese encephalitis virus (JEV) strains from Cx. tritaeniorhynchus pools were detected. Seven strains of insect-specific flaviviruses (ISFVs), including two Aedes flavivirus (AeFV) and Yunnan Culex flavivirus strains each, one Culex theileri flavivirus, Yamadai flavivirus (YDFV) and Anopheles-associated flavivirus (AAFV) strains each were detected in Aedes albopictus, Cx. tritaeniorhynchus, Cx. vagans, Cx. pseudovihnui, and An. sinensis pools, respectively. The whole-genome was successfully amplified in one strain of JEV and AeFV each. Phylogenetic analysis using the E gene placed all the newly detected JEV strains into the GI-b genotype. They showed highly nucleotide identities, and were most closely related to the strain detected in Tengchong in 2010. The comparison of the E protein of JEV strains and vaccine-derived strain, showed six amino residue differences. The bias-corrected maximum likelihood estimation values (and 95% confidence interval) for JEV in Cx. tritaeniorhynchus collected in Tengchong in 2018 were 2.4 (1.4–3.9). Conclusions: A potential Japanese encephalitis epidemic focus with the abundance of host mosquitoes and high JEV infection rate was observed in Tengchong. In addition, at least five species of ISFVs co-circulate in this area. This study highlights the importance of widespread and sustained mosquito-based arbovirus surveillance in local areas to prevent the transmission of JEV, and other emerging/re-emerging mosquito-borne pathogens. [ABSTRACT FROM AUTHOR]

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Siliceous-sulphate rock coatings were observed at Zhenzhu Spring, an acid sulphate hot spring in the Tengchong volcanic field, China. These rock coatings are mainly formed of gypsum and amorphous silica. Some alum-(K), voltaite, α-quartz and muscovite were also found. Four different laminae are developed in the rock coatings: gypsum layer, tight siliceous layer, tabular siliceous layer and siliceous debris layer. The gypsum layer is located at the top of the rock coatings, while other siliceous layers appear below the gypsum layer. Geochemical modelling of the fluids was performed to identify the mechanisms responsible for the formation of gypsum and amorphous silica. The results indicated that the occurrence of gypsum is related to the acid-fog deposition and amorphous silica mainly originates from spring water. Fog deposition provided the rock coatings with abundant SO42− and Ca, and the subsequent complete evaporation of the condensed fluids produced gypsum. Seasonal climate change (especially variation in rainfall) determines the fluctuations of capillary action and dissolution. Rainfall events in the wet season led to periods of non-precipitating gypsum and promoted the capillary rise of the spring water. Slightly diluted capillary water (a small amount of rainwater) covered the rock coatings, formed a tight siliceous layer on the rock-coating surface and/or filled the pores among the gypsum crystals forming many tabular siliceous aggregates. Heavy rainfall (high dilution), however, resulted in non-precipitating amorphous silica and accelerated the gypsum dissolution, leaving tabular pores around tabular siliceous aggregates and forming a tabular siliceous layer. [ABSTRACT FROM AUTHOR]

The Zhenzhu Spring, located in the Tengchong volcanic field, Yunnan, China, is an acid hot spring with high SO42− concentrations and intense acid aerosol generation. In order to understand the formation mechanism of sulfate minerals at the Zhenzhu Spring and provide a better insight into the sulfur isotope geochemistry of the associated Rehai hydrothermal system, we investigated the spring water hydrochemistry, mineralogy and major-element geochemistry of sulfate minerals at the Zhenzhu Spring together with the sulfur-oxygen isotope geochemistry of sulfur-containing materials at the Rehai geothermal field and compared the isotope results with those in other steam-heated environments. Subaerial minerals include a wide variety of sulfate minerals (gypsum, alunogen, pickeringite, tamarugite, magnesiovoltaite and a minor Mg–S–O phase) and amorphous SiO2. The δ34S values of the subaerial sulfate minerals at the Zhenzhu Spring varied subtly from –0.33 to 1.88‰ and were almost consistent with the δ34S values of local H2S (–2.6 to 0.6‰) and dissolved SO42− (–0.2 to 5.8‰), while the δ18O values (–8.94 to 20.1‰) were between that of the spring waters (–10.19 to –6.7‰) and atmospheric O2 (~23.88‰). The results suggest that most of the sulfate minerals are derived from the oxidation of H2S, similar to many sulfate minerals from modern steam-heated environments. However, the rapid environmental change (different ratio of atmospheric and water oxygen) at the Zhenzhu Spring accounts for the large variation of δ18O. The formation of subaerial sulfate minerals around the Zhenzhu Spring is related to acid aerosols (vapour and acid water droplets). The intense activity of spring water around vents supply the aerosol with H2SO4 (H2S oxidation and acid water droplets formed by bubble bursting) and few cations. Deposition of the acid sulfate aerosol forms the acid condensate, which attacks the underlying rocks and releases many cations and anions to form subaerial sulfate minerals at the Zhenzhu Spring. [ABSTRACT FROM AUTHOR]

Abstract Reshuitang is an important active hydrothermal area in the Tengchong geothermal field and is characterized by many hot springs and their associated deposits. Detailed mineralogical, crystal morphological, and stable isotopic investigations of the smooth slope fossil travertines at Reshuitang and hydrochemical studies of two active springs around the fossil travertines were conducted to study their genesis. The results show that 1) the modern springs discharge waters with high temperature (>70 °C), near-neutral pH (6.3–8.34), and high saturation indices of calcite and aragonite; 2) the fossil travertines contain calcite and small amounts of Mn-Fe oxides, halite, thenardite, and non‑carbonate debris; 3) the calcite include ray crystals, dendrite crystals, platy crystals, and spike crystals; and 4) δ13C and δ18O of the fossil travertines at Reshuitang range from −1.59‰ to −0.87‰ and 6.48‰ to 7.80‰, respectively. According to comparison between the travertines at Reshuitang and other travertines in Tengchong, all these travertines are thermogene travertines, with a large contribution of mantle degassing to their parent CO 2 , but are formed at different temperatures. The fossil travertines at Reshuitang, similar to those at Shuzhishi, are formed at high temperatures (near 100 °C), which results in weak microbial activities during the formation of the fossil travertines. Most of the calcite crystals at Reshuitang were non-equilibrium products precipitated directly from the spring waters during the deposition process, while the spike crystals originated from diagenetic dissolution of large calcite crystals. Comparison between the fossil travertines at Reshuitang and other smooth slope travertines from other areas shows these smooth slope travertines have different lithofacies and fabrics. In smooth slope environments, temperature may control the distribution and development of microbes and the intensity of CO 2 degassing, and consequently cause the precipitation of contrasting fabrics and lithofacies. [ABSTRACT FROM AUTHOR]

Recently identified Early Jurassic, Early Cretaceous, and Late Cretaceous granites of the Tengchong terrane, SW China, help to refine our understanding of the Mesozoic tectonic-magmatic evolutionary history of the region. We present new zircon U-Pb geochronological, Lu-Hf isotopic and geochemical data on these rocks. The zircon LA-ICP-MS U-Pb ages of the Mangzhangxiang, Laochangpo, and Guyong granites, and Guyong granodioritic microgranular enclaves are 185.6, 120.7, 72.9, and 72.7 Ma, respectively. Geochemical and Hf isotopic characteristics suggest the Mangzhangxiang and Laochangpo S-type granites were derived from partial melting of felsic crust and that the Guyong I-type granite and associated MMEs were generated through magma mixing/mingling. Mesozoic magmatism in the Tengchong terrane can be divided into three episodes: (1) the Triassic syn- and post-collisional magmatic event was related to the closure of the Palaeo-Tethyan Ocean, as represented by the Changning-Menglian suture zone; (2) the Jurassic to Early Cretaceous magmatism was related to the subduction of the Meso-Tethyan oceanic crust, as represented by the Myitkyina ophiolite belt; and (3) the Late Cretaceous magmatism was related to the subduction of the Neo-Tethyan oceanic crust, as represented by the Kalaymyo ophiolite belt. [ABSTRACT FROM AUTHOR]

New data from mineralogy, geochemistry, zircon U–Pb dating, and Hf isotopes have revealed Late Cretaceous to Eocene magmatic intrusions in the Tengchong terrane and constrained the origin, tectonic setting, and characteristics of tin‐bearing and barren granitoids. We divide the studied granitoids into two groups: (a) the Late Cretaceous Zhinaxiang (70 Ma) and Early Paleocene Dazhupeng (65 Ma) S‐type barren granites and (b) the Eocene Lailishan A2‐type tin‐bearing granite (50 Ma). All these granitoids display Si‐ and K‐rich and calc‐alkaline characteristics and have similar chondrite‐normalized rare earth element patterns. However, geochemical differences do exist between the two groups of granites. The Zhinaxiang and Dazhupeng S‐type granites are slightly peraluminous, enriched in large‐ion lithophile elements (e.g., Rb and K), and depleted in high‐field‐strength elements (e.g., Nb, Ta, Zr, and Hf), whereas the Lailishan A2‐type granite has higher TFe2O3, high‐field‐strength element content, and Ga/Al ratios. The geochemical and Hf isotopic data indicate that the granites in this study were generated by partial melting of Paleoproterozoic metasedimentary rocks. Due to the subduction of the Neo‐Tethyan Ocean beneath the Eurasian plate, the Zhinaxiang and Dazhupeng S‐type granites were formed in a thickened‐crustal environment, whereas the Lailishan A2‐type granite was emplaced in a post‐collisional extensional setting attributed to slab break‐off. By comparison between tin‐bearing and barren granites, we propose that the Sn mineralization could be related to relatively high‐temperature and low‐pressure crystallization conditions. [ABSTRACT FROM AUTHOR]

Cenozoic intra-plate volcanism in Southwest China allows insights into modes of melting and the composition of the sub-continental lithospheric mantle (SCLM). The late Cenozoic Tengchong Volcanic Field (TVF), located in the Yunnan Province Northeast of the Himalayas, comprises a cluster of mafic continental intraplate lavas, represented by 68 volcanic cones and spanning an area of ca. 800 km 2 . Major and trace element data and Sr-Nd-Pb-Hf isotope ratios of 18 newly sampled rocks from the area are used to identify the composition of their source in the SCLM. Indices of magmatic differentiation are correlated with isotope composition, marking a classic case of assimilation-fractional-crystallization (AFC) during petrogenesis. The most primitive samples, identified on the basis of element and isotope compositions, are interpreted to be directly derived from the metasomatised mantle underneath south-western China. Modelling of a best-fit scenario indicates that the isotope and trace element character of these samples can be reproduced by ca. 1% partial melting of a metasomatised mantle source, composed of depleted MORB mantle infused with 1% addition of a bulk global subducting sediment (GLOSS) component. Average isotope compositions of 87 Sr/ 86 Sr = 0.705861, 143 Nd/ 144 Nd = 0.512675, 176 Hf/ 177 Hf = 0.282962, 206 Pb/ 204 Pb = 18.305, 207 Pb/ 204 Pb = 15.642 and 208 Pb/ 204 Pb = 38.948 are proposed for the present-day enriched part of the SCLM. The origin of the isotopic signatures is ascribed to modifications of parent-daughter ratios in the SCLM by past subduction-related metasomatism, possibly in the form of sediment mélange diapirs. This implied that the mantle source of TVF lavas is not, as previously proposed, related to enriched geochemical reservoirs (EM-1, EM-2) associated with mantle plume activity or to so-called Dupal or Indian asthenospheric mantle. Instead, it is argued that time-integrated parent-daughter fractionation occurred long before India-Asia collision and this produced reservoirs with isotopic compositions that resemble some but not all aspects of the Dupal isotope signature. In analogy, so-called Dupal isotope signatures elsewhere may also be the result of contamination of the mantle by a crustal component, most likely subducted sediment. [ABSTRACT FROM AUTHOR]

To detect arsenic geochemistry and evaluate its environmental risk, 30 geothermal water samples were collected from Rehai and Ruidian geothermal fields of Tengchong, China. There were three main water types including SO 4 and Na-Cl-HCO 3 types in Rehai and Na-HCO 3 type in Ruidian. Arsenic concentrations ranged from 22.1 to 1150.3 μg L −1 . Relative high concentrations of arsenic with an average of 495.1 μg L −1 , as well as K, Na, F, Cl, Li and B, were detected in neutral or alkaline geothermal water samples, which suggested that rock leaching in geothermal reservoir was the main resource of arsenic enrichment in geothermal water. Comparatively, those acid geothermal water samples which were formed by vapor rich in H 2 S condensing and oxidizing in the shallow groundwater or surface water had lower arsenic concentrations with an average of 77.1 μg L −1 . The ratios of arsenite to total arsenic widely ranged from 0.01 to 0.97 and were determined by mixing proportions of geothermal water and shallow groundwater or surface water. Furthermore, there was a significantly positive correlation between arsenic with HCO 3 (R = 0.81, P = 0.01). These results implied that shallow groundwater or surface water in Tengchong geothermal area had been probably contaminated by arsenic due to the mixing of geothermal water. [ABSTRACT FROM AUTHOR]

Numerous present-day hot springs and associated ancient Lianghe gold deposit occur in the central Tengchong block, SW China, associated with oceanic crust subduction. From the center outwards, the alteration zones in the hot spring of the Rehai consist of alunite and silica in a breccia zone, a kaolinite and illite zone, and a chlorite, illite, kaolinite zone. The gas phase in the hot spring is dominated by CO 2 with δ 13 C ranging from −4.5‰ to −7.2‰. These features indicate a major magmatic origin of the hot spring gas. The 3 He/ 4 He ratios in the gas from central Tengchong vary from 1.56 to 5.88, approaching to those of the MORB. This is probably related to the ongoing subduction of the Indian plate beneath the Tengchong block. The hot spring waters in the central Tengchong block have much higher content of Au and other elements, e.g., Ag, As, Sb, and Tl, than other typical hot springs, such as Hasbrouck, Sulfer, etc. in the world. The hot springs with more mantle gas contribution and higher water temperature show more elevated Au contents, which implies that the metal in the hot spring was most likely contributed from the magmatic gas. The compiled D-O isotopes of the hot spring waters from previous studies suggest that they are primarily derived from meteoric water. A genetic model for the hot spring system in the central of Tengchong has been tentatively established. The gold-charged hot spring is genetically connected to an active magma chamber, which was produced by subduction of oceanic crust. The chamber is driving long-term surface meteoric circulation and constantly releasing magmatic volatiles enriched with metals. As hot spring water mixed with magmatic volatiles, causing decompression-boiling and forming hydraulic fractures to penetrate the roof of siliceous sinter, which induced the continuing metal deposition and formed the Lianghe hot spring. [ABSTRACT FROM AUTHOR]

SHRIMP zircon Pb/U dating of Cenozoic volcanic rocks in the Tengchong area, western Yunnan Province, China, shows that the dacite and andesitic breccia lavas from Qushi village were intruded at 480 ± 10 ka and 800 ± 40 ka, respectively. Moreover, Pb/U dating of trachyandesite from Tuantian village and olivine basalt from Wuhe village give weighted mean 206 Pb/ 238 U ages of 2.82 ± 0.08 Ma and 12.28 ± 0.30 Ma. Corrections for initial 230 Th disequilibrium of zircon were used for the former two younger ages. The Tengchong volcanic rocks have a large range of SiO 2 (48.6–66.9 wt.%) and mostly belong to a high-K calc-alkaline series. The lavas originated from heterogeneous sources and were modified by subsequent fractional crystallization. The REE and other trace element patterns of the Tengchong volcanic rocks resemble magmas having a large component of continental crust. All have similar degrees of LREE and HREE fractionation and are enriched in LILE, La, Ce and Pb, with depletions in Nb, Ta, Ti, Sr and P relative to primitive mantle. Zircon δ 18 O values of 6.96 ± 0.17 and 7.01 ± 0.24‰ and highly varied negative ε Hf (t) values of − 1.5 to − 11.0 and − 10.3 to − 13.7, as well as the presence of inherited zircon grains in the studied samples, indicate that the magmas contain crustal material on a large scale. The Tengchong volcanic rocks have HFSE ratios (e.g., Nb/Ta, La/Nb, Zr/Y) similar to continental flood basalts, indicative of an intra-plate extensional tectonic setting. Widespread distributed faults might have facilitated upwelling of mantle-derived melts and eruptions from shallow crustal magma chambers to form the large volcanic field. [ABSTRACT FROM AUTHOR]

The Tengchong terrane comprises a sequence of linear dome-like zones, cored by granite and migmatitic layers. These cores are mantled by predominantly gneiss and subordinate schist sequences, decreasing in deformation intensity outward from extensive mylonitization to weak mylonitization. The pre-doming deformation was characterized by the formation of large-scale top-to-the-east shearing (D1) in the gneiss terrane, locally preserved flat-lying foliation (S1), weak folding (F1) and emplacement of the Mangbang granite during the Cretaceous (114-104 Ma). The second stage of deformation (D2) consisted of map-scale east-verging folds (F2, dome amplification) and minor lateral strike-slip shear zones between the anticlines in the gneiss and migmatitic sequences. Extensive partial melting and emplacement of 67-30 Ma synkinematic granitoid bodies/veins occurred, leading to the emplacement of wedges of granite into the easterly directed F2 fold cores. These wedges formed kilometer-scale granitoid domes. The post-doming D3 deformation with transpression recorded strain partitioning with simple shear-dominated high-strain zones along the Gaoligong and Nabang dextral lateral strike-slip shear zones (active during 30-11 Ma). Late transtensional deformation (D4) during cooling of the entire terrane involved the localized low-temperature Gaoligong west and east detachment faults that controlled the late exhumation of the Gaoligong metamorphic zone (since 10 Ma). Our structural observations, combined with previous studies, suggest that this style of doming is a representative type of intra-continental deformation in the Cenozoic during the oblique India-Asia collision. The actual dome shapes reflect formation of antiforms during compression-dominated transpression, prior to localized strike-slip shearing, in the accommodation belt around the Eastern Himalayan Syntaxis. Vertical exhumation of crustal material by contractional doming played an important role in absorbing the vast majority of the internal deformation of crustal fragments during oblique collision. [ABSTRACT FROM AUTHOR]

Post-collisional volcanic rocks on the Tibetan Plateau and its margins contain valuable information about the geodynamic processes associated with this Cenozoic continent-continent collision. The Quaternary Tengchong volcanic field at the southeastern margin of the Tibetan Plateau formed high-potassium calc-alkaline volcanic rocks. Herein, we present comprehensive Nd-Sr-Pb-Hf isotopic and elemental data for trachybasalts, basaltic trachyandesites, and trachyandesites from four Quaternary Tengchong volcanoes (Maanshan, Dayingshan, Heikongshan, and Laoguipo) in order to understand their magma genesis and evolution as well as tectonic significance. Good correlations between SiO 2 content and the ratios 87 Sr/ 86 Sr, 143 Nd/ 144 Nd, 206 Pb/ 204 Pb, and 177 Hf/ 176 Hf for these Quaternary volcanics strongly suggest that the combined assimilation and fractional crystallization (AFC) was an important process in the origin of basaltic trachyandesites and trachyandesites. High Y and Yb contents and low Sr/Y ratios of these basaltic trachyandesites and trachyandesites are uncharacteristic of adakites that formed by partial melting of eclogitic lower crust or partial melting of basaltic oceanic crust with eclogite as a restite. A combined assimilation-fractional crystallization model is proposed for these basaltic trachyandesites and trachyandesites. Nd-Sr-Pb-Hf isotopes for the uncontaminated Tengchong magma (trachybasalts with SiO 2 < 52.5 wt.% and MgO > 5.5% wt.%) reflect a heterogeneous enriched mantle source. High Th/U, Th/Ta, and Rb/Nb ratios and Nd-Sr-Pb-Hf isotope characteristics of the uncontaminated magmas suggest that the enriched mantle beneath Tengchong formed as a result of subduction of clay-rich sediments, which probably came from the Indian continental plate. Partial melting of the enriched mantle was generated by deep continental subduction coupled with recent regional extension in the Tengchong area. [ABSTRACT FROM AUTHOR]

The newly discovered Jiaojiguan deposit, a medium-scale skarn iron-tin polymetallic deposit on the Sino-Burma boundary of Yunnan Province (SW China), is spatially associated with the biotite monzonitic granite. Here, we report newin situzircon LA-MC-ICP-MS U–Pb ages, trace element and Hf isotope data from the granite, and U–Pb dating ages of cassiterite from the ore bodies. In this study, we obtain a weighted mean206Pb/238U age of 124.1 ± 1.4 Ma for the zircon and a207Pb/206Pb-238U/206Pb intercept age of 123.8 ± 2.2 Ma for the cassiterite. The granite crystallized during the Early Cretaceous, with zircons exhibitingεHf(t) values from −5.8 to −0.6 and two-stage Hf model ages (TDM2) of 1.21–1.54 Ga. The close temporal and spatial links between pluton emplacement and ore-forming events suggest that magmatic-hydrothermal events were the key factors that triggered the genesis of the iron-tin polymetallic deposits in the area. Regional geochronological data show that tin mineralization took place three times during the Cretaceous–Palaeogene in the Tengchong block due to re-melting of the underlying supposed Proterozoic (1.5 ± 0.5 Ga) Sn-rich strata/materials. Compared with those in the Bangong–Nujiang metallogenic belt (BNMB), we propose that the Cretaceous iron-tin polymetallic mineralization events in Tengchong–Baoshan closely resemble those of the Bangong–Nujiang belt in northern Tibet, both of which have experienced similar tectono-magmatic-metallogenic histories since the Mesozoic. [ABSTRACT FROM PUBLISHER]

Archaeal viruses are one of the most mysterious parts of the virosphere because of their diverse morphologies and unique genome contents. The crenarchaeal viruses are commonly found in high temperature and acidic hot springs, and the number of identified crenarchaeal viruses is being rapidly increased in recent two decades. Over fifty viruses infecting the members of the order Sulfolobales have been identified, most of which are from hot springs distributed in the United States, Russia, Iceland, Japan, and Italy. To further expand the reservoir of viruses infecting strains of Sulfolobaceae , we investigated virus diversity through cultivation-dependent approaches in hot springs in Tengchong, Yunnan, China. Eight different virus-like particles were detected in enrichment cultures, among which five new archaeal viruses were isolated and characterized. We showed that these viruses can infect acidophilic hyperthermophiles belonging to three different genera of the family Sulfolobaceae , namely, Saccharolobus , Sulfolobus , and Metallosphaera . We also compared the lipid compositions of the viral and cellular membranes and found that the lipid composition of some viral envelopes was very different from that of the host membrane. Collectively, our results showed that the Tengchong hot springs harbor highly diverse viruses, providing excellent models for archaeal virus-host studies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Feng, Li, Tian, Yang, Liu, Zhang and Zeng.)

A new facultative chemolithoautotrophic arsenite-oxidizing bacterium TCC9-4 was isolated from a hot spring microbial mat in Tengchong of Yunnan, China. This strain could grow with arsenite (AsIII) as an energy source, CO2-HCO3- as a carbon source and oxygen as the electron acceptor in a minimal salts medium. Under chemolithoautotrophic conditions, more than 90 % of 100 mg/L AsIII could be oxidized by the strain TCC9-4 in 36 hours. Temperature was an important environmental factor that strongly influenced AsIII oxidation rate and AsIII oxidase (Aio) activity; highest Aio activity was found at the optimal temperature of 40 oC. Addition of 0.01 % yeast extract enhanced the growth significantly, but delayed the AsIII oxidation. On the basis of 16S rDNA phylogenetic sequence analysis, strain TCC9-4 was identified as Anoxybacillus flavithermus. To our best knowledge, this is the first report of arsenic oxidation by Anoxybacillus flavithermus. The results of this study expand our current understanding of microbially-mediated arsenic oxidation in hot spring.

Surface meteorological observation data and aerosol optical depth (AOD) data from 1951-2011 were analyzed for Tengchong city, which is a clean city in Southwest China. A significant reduction of light rain, accompanied by an increase of visibility and a decrease of AOD, was observed. Thus, the observed light rain reduction in Tengchong was not associated with an increase of aerosols. The main cause of the reduction in light rain was the decrease of relative humidity in the layer between 850 to 500 hPa, which was induced mainly by the increase of temperature. This counterexample indicates that there are some evidences on the short-term scale, but the depression of light rain by aerosols on the long-term scale remains controversial. [ABSTRACT FROM AUTHOR]

Two closely related thermophilic bacterial strains, designated YIM 71031 and YIM 71039, were isolated from a hot spring in Tengchong county, Yunnan province, south-western China. The novel isolates were observed to be Gram-negative, aerobic, rod-shaped and yellow-pigmented bacteria. The strains were found to be able to grow at 37-65 °C, pH 6.0-9.0 and with a NaCl tolerance up to 1.0 % (w/v). Phylogenetic analysis based on 16S rRNA gene sequences placed these two isolates in the genus Meiothermus. They were found to be closely related to Meiothermus timidus DSM 17022 (98.6 % similarity), and formed a cluster with this species. The predominant menaquinone was identified as MK-8 and the major fatty acids (>10 %) as anteiso-C, iso-C, anteiso-C, iso-C and C. The genomic DNA G+C contents of strains YIM 71031 and YIM 71039 were determined to be 64.0 and 65.4 mol%, respectively. DNA-DNA hybridizations showed low values between strains YIM 71031 and YIM 71039 and their closely related neighbour M. timidus DSM 17022. Morphological phylogenetic and chemotaxonomic results suggest that strains YIM 71031 and YIM 71039 are representatives of a new species within the genus Meiothermus, for which the name Meiothermus roseus sp. nov. is proposed. The type strain is YIM 71031 (=KCTC 42495 =NBRC 110900). [ABSTRACT FROM AUTHOR]

Two aerobic, Gram-positive actinomycetes, designated YIM 77502 and YIM 77510, were isolated from geothermally heated soil of Tengchong county, Yunnan province, south-west China. The taxonomic position of strains YIM 77502 and YIM 77510 were investigated by a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains YIM 77502 and YIM 77510 belong to the genus Actinomadura. Both strains form extensively-branched substrate and aerial mycelia which differentiated into short spore chains. The cell wall of the two strains contained meso-diaminopimelic acid, while the whole-cell sugars detected were glucose, madurose, mannose and rhamnose. The polar lipid profile of strain YIM 77502 was found to consist of diphosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylinositol, two unidentified phospholipids and an unidentified polar lipid, while strain YIM 77510 consisted of diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylinositol. The respiratory quinones of strains YIM 77502 and YIM 77510 were MK-9(H) and MK-9(H). The major fatty acids (>10 %) of strain YIM 77502 were C, iso-C, C10-methyl and iso-C, and those of strain YIM 77510 were iso-C, C10-methyl and iso-C. The G+C contents of strains YIM 77502 and YIM 77510 were determined to be 71.3 and 70.2 mol%, respectively. The DNA-DNA hybridization values of strains YIM 77502, YIM 77510 and their closest phylogenetic neighbours Actinomadura echinospora BCRC 12547 and Actinomadura umbrina KCTC 9343 were less than 70 %. Based on the morphological and physiological properties, and phylogenetic analyses, strains YIM 77502 and YIM 77510 are considered to represent two novel species of the genus Actinomadura, for which the names Actinomadura amylolytica sp. nov. (type strain YIM 77502 = DSM 45822 = CCTCC AA 2012024) and Actinomadura cellulosilytica sp. nov. (type strain YIM 77510 = DSM 45823 = CCTCC AA 2012023) are proposed. [ABSTRACT FROM AUTHOR]

Reservoir temperature estimation is vitally important for assessing the exploitation potential of a geothermal field. In this study, the concentrations of major chemical constituents in geothermal water sampled from boiling and hot springs in the Tengchong hydrothermal area were measured, and quartz and cationic solutes geothermometers were used to calculate subsurface temperatures. Log (Q/K) diagrams and Na-K-Mg triangular diagrams were applied to evaluating the equilibrium status of geothermal water samples with regard to reservoir minerals, and results were used to select suitable geothermometers. The results show that samples RH01, RH03, RH04, RH05, and LL16 were in or very close to full equilibrium with the selected minerals, and therefore a Na-K geothermometer is appropriate. A K/Mg geothermometer, however, is applicable to LP08 and PZH18 whose chemical compositions adjusted to the shallow reservoir temperatures during their re-equilibrium processes. In contrast, cationic solute geothermometers are unsuitable for SQ20 and RH07, which are categorized as immature water in the Na-K-Mg diagram; a quartz geothermometer was adopted to evaluate the corresponding subsurface temperatures of these samples. According to the reservoir temperature estimation made in this study, there is at least one high-temperature reservoir below Rehai with a possible temperature range of 210-270 °C. [ABSTRACT FROM AUTHOR]

The Tengchong volcanic field east of the Burma arc in SW China comprises numerous Quaternary volcanoes. The volcanic rocks can be grouped into four units, numbered 1–4 from oldest to youngest. Units 1, 3 and 4 are composed of trachybasalt, basaltic trachyandesite and trachyandesite, respectively, whereas Unit 2 consists of hornblende dacite. Primary minerals in the dacite include plagioclase, clinopyroxene, amphibole and magnetite, all set in a glassy groundmass. Some of the dacites are moderately to highly weathered and show effects of low temperature alteration, with loss on ignition (LOI) up to 9.6 wt% and positive correlations of LOI with Al 2 O 3 , but negative correlations with SiO 2 , CaO and Na 2 O. Fresh dacites (LOI <3 wt%) belong to the calk-alkaline series and have pronounced negative Ti, Nb and Ta anomalies. They have whole-rock 87 Sr/ 86 Sr ratios ranging from 0.7090 to 0.7101, εNd values from −10.8 to −11.8, and εHf values from −5.1 to −6.8. Many of the large plagioclase crystals in the fresh dacites have reverse zoning, ranging from An 55 in the cores to An 72 in the rims. The smaller phenocrysts have relatively uniform An values between 56 and 50. One plagioclase crystal has an An value of 33.5. Plagioclase in the fresh dacite has relatively high Sr contents and 87 Sr/ 86 Sr ratios ranging from 0.7050 to 07125 except for one value of 0.7516, whereas plagioclase in the altered dacite has low Sr contents and highly variable Sr isotopic compositions (0.7039–0.7138), indistinguishable from those of the fresh rocks. Both An values and Sr isotopic compositions of the plagioclase indicate mixing of mantle- and crustally-derived magmas. We therefore propose that mantle-derived basaltic magma caused partial melting of the lower–middle crust and that mixing of the mafic and felsic magmas produced the dacite in staging magma chambers. The dacites contain minerals crystallized from both the mafic and felsic magmas, as well as a few xenocrysts plucked from the country rocks. [ABSTRACT FROM AUTHOR]

H-shaped glycerol dialkyl glycerol tetraethers (H-GDGTs), also called glycerol monoalkyl glycerol tetraethers (GMGTs), are a unique group of membrane lipids found in several lineages of Euryarchaeota and Crenarchaeota . Their function in these taxa is, however, not well understood. Here we show their presence in both core lipid and polar lipid fractions from microbial biomass sampled from hot springs in Tibet, China (21.9–80.0 °C; pH 7.0–9.1), Tengchong, China (55.1–93.6 °C; pH 2.5–9.4) and Yellowstone National Park (YNP), USA (16.3–86.7 °C; pH 2.1–9.6) using high performance liquid chromatography–mass spectrometry. The number of cyclopentyl rings ranged from zero (H-GDGT-0) to six (H-GDGT-6) in lipid fractions in Tengchong and YNP and from zero to four (H-GDGT-4) in those from Tibet. While H-GDGT-0 was the most abundant H-GDGT in Tibetan springs, H-GDGT-4 predominated in Tengchong and H-GDGT-6 predominant in YNP, resulting in higher ring indices in the latter springs. While pH appeared to be the most important factor affecting the variation in the relative abundance and average number of cyclopentane rings in H-GDGTs from YNP communities, both temperature and pH appeared to be important controls on the abundance of H-GDGT lipids in Tengchong communities, whereas neither pH nor temperature appeared to influence the abundance or average number of cyclopentane rings in H-GDGTs from Tibetan spring communities. Furthermore, the relative abundance of H-GDGTs to total iGDGTs was greater in hot springs with acidic pH, particularly those from YNP. This finding, coupled with taxonomic profiling of archaeal 16S rRNA genes recovered from the same YNP springs, indicates that H-GDGTs in acidic springs may be synthesized by members of the archaeal order Thermoplasmatales , which are adapted to acidic pH. [ABSTRACT FROM AUTHOR]

A Streptomyces-like actinomycete strain, designated as YIM 78087, was isolated from a sediment sample collected from Hehua hot spring in Tengchong, Yunnan province, south-west China. The taxonomic position of strain YIM 78087 was investigated by a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain YIM 78087 belongs to the genus Streptomyces and is closely related to Streptomyces fimbriatus DSM 40942, Streptomyces marinus DSM 41968 and Streptomyces qinglanensis DSM 42035 (97.18, 97.05 and 97.1 % similarity, respectively). Combined with the low values of DNA-DNA hybridization between strain YIM 78087 and its closest neighbours, these analyses indicated that this new isolate represents a different genomic species in the genus Streptomyces. The predominant menaquinones of strain YIM 78087 were identified as MK-9 (H) and MK-9 (H). The major fatty acids were identified as anteiso-C (28.4 %), anteiso-C (23.0 %) and iso-C (15.1 %). The whole-cell hydrolysates found to contain glucose, mannose and ribose. The DNA G+C content was determined to be 73.0 mol%. Based on the comparative analysis of phenotypic and genotypic characteristics, it is proposed that strain YIM 78087 represents a novel species of the genus Streptomyces, for which the name Streptomyces calidiresistens sp. nov., is proposed. The type strain is YIM 78087 (=BCRC 16955=DSM 42108=JCM 19629). [ABSTRACT FROM AUTHOR]

An alkalitolerant, thermotolerant and Gram-stain negative bacterium, designated strain YIM 78007, was isolated from an alkaline geothermal soil sample from Hehua hot spring, Tengchong, Yunnan province, south-west China. Cells of strain YIM 78007 were observed to be aerobic and short rod-shaped. The colonies were observed to be orange-red, convex and circular. 16S rRNA gene sequence-based phylogenetic analysis showed that strain YIM 78007 clustered with members of the genus Roseomonas (with similarities from 97.2 to 92.2 %). Optimal growth of strain YIM 78007 occurs at 40-50 °C and pH 8.0-10.0. The predominant ubiquinone was identified as Q-10 and the major fatty acids were identified as C ω7c and C. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified aminolipids and one unknown phospholipid. The G + C content of the genomic DNA was determined to be 63 mol %. The levels of DNA-DNA hybridization relatedness between strain YIM 78007 and its closet neighbours ( Roseomonas lacus JCM 13283 and Roseomonas terrae JCM 14592) were well below the threshold required for the proposal of a novel species. The results of physiological and biochemical characteristics, the phylogenetic analysis, as well as low DNA-DNA hybridization values, allowed the phenotypic and genotypic differentiation of strain YIM 78007 from its closest phylogenetic neighbours. Therefore, strain YIM 78007 is considered to represent a novel species of the genus Roseomonas, for which the name Roseomonas alkaliterrae sp. nov. is proposed. The type strain is YIM 78007 (=BCRC 80644 = JCM 19656). [ABSTRACT FROM AUTHOR]

Abstract: We report U-series disequilibrium data in the youngest volcanic rocks from Maanshan, Dayingshan and Heikongshan volcanoes in the Tengchong volcanic field, representing the only 3 volcanoes from the Indo-Asian suture zone (southwestern Tibet to western Yunnan) that are young enough to preserve 238U–230Th disequilibrium. The most striking feature of these young Tengchong lavas is their extremely low (230Th/232Th) (0.303 to 0.376) and (238U/232Th) (0.289 to 0.360) activity ratios (or ultra-high Th/U concentration ratio). These young lavas also show small to moderate (4% to 10%) 230Th excesses. Such 230Th excesses, together with tomographic results, suggest that partial melting initiated at depths greater than 75km in the garnet stability field. U-series isotope data, together with major and trace element and Nd–Sr–Pb isotope data, indicate that Tengchong lavas are derived from partial melting of an enriched subcontinental lithospheric mantle. The ultra-high melt Th/U concentration ratios of 9.5±0.7 further indicate recycling of continentally derived clay-rich mature sediments or mudstones into the SE Tibetan mantle. The materials with ultra-high Th/U ratios may come from the clay-rich mature sediments from Indian Ocean or Neo-Tethyan Ocean or the mudstones/shales from the subducted Indian continental plate. [Copyright &y& Elsevier]

Abstract: To constrain the paleoposition of the Tengchong block within Gondwana during the Early Paleozoic, we performed in-situ U–Pb and Hf isotope analyses on detrital zircons from Carboniferous strata in the Tengchong block. The age distributions yield dominant Neoarchean (~2.5Ga), Mesoproterozoic (1.7–1.4Ga), Grenvillian (~0.95Ga), and Pan-African (0.65–0.5Ga) age groups. Hf isotope compositions of Mesoproterozoic, Grenvillian, and Pan-African zircon age groups exhibit wide range of ε Hf(t) suggesting their diverse sources. The oldest Hf model ages indicate that the source magma included reworked Eoarchean (3.8–3.7Ga) crustal materials. The remarkable resemblance of zircon age spectra and Hf isotopes from the Tengchong block with those from Tethyan Himalayan, western Qiangtang and Indochina suggests that the Tengchong block was located along the Indian margin of Gondwana during the Early Paleozoic. In Grenvillian and Pan-African, crustal growth for the source areas was insignificant. [Copyright &y& Elsevier]

Hot springs at Gongxiaoshe and Zhuyuan (maximum temperatures of 73 to 84°C, respectively) are characterized by deposits formed of calcite, aragonite, non-crystalline Si-Mg-Fe deposits, and minor amounts of barite and gypsum. The deposits at Gongxiaoshe are formed largely of alternating calcite and aragonite laminae, whereas those at Zhuyuan are formed largely of calcite. The calcite is in the form of: (i) pseudodendrites that grew as sub-crystals stacked upon each other; and (ii) unattached euhedral and incompletely formed dodecahedral and rhombohedral crystals. Amorphous Ca CO3, formed of nanoparticles <1 μm long, is common in some of the Zhuyuan deposits, but minor in the Gongxiaoshe deposits. The morphologically diverse arrays of aragonite crystals that lie parallel to bedding were not nucleated on a growth surface. Many substrates in these deposits are covered with reticulate coatings that are formed largely of Si and Mg with minor Fe and micro-granular coatings that are formed largely of Si and Fe. Biofilms, with their extracellular polymeric substances, and microbes are common at both springs. The compositionally and crystallographically diverse precipitates at these two springs are attributed to a biologically influenced model with precipitation taking place in micro-domains that developed in the extracellular polymeric substances. According to this model, precipitation varied at the micron-scale influenced by the elemental concentrations that developed in the hydrogel of extracellular polymeric substances. Critically, the very low preservation potential of the extracellular polymeric substance and its formative microbes means that the precipitates will rapidly lose evidence of their biotic origin. The compositional diversity of the precipitates, the crystallographic diversity of the calcite and aragonite with numerous incompletely formed crystals, and local concentrations of Si, Mg and Fe may, however, serve as proxies of that biologically influenced precipitation. [ABSTRACT FROM AUTHOR]

A total of 12 samples were collected from the Tengchong geothermal areas of Yunnan, China, with the goal to assess the arsenite (AsIII) oxidation potential of the extant microbial communities as inferred by the abundance and diversity of the AsIII oxidase large subunit gene aioA relative to geochemical context. Arsenic concentrations were higher (on average 251.68 μg/L) in neutral or alkaline springs than in acidic springs (on average 30.88 μg/L). aioA abundance ranged from 1.63 × 10 to 7.08 × 10 per ng of DNA and positively correlated with sulfide and the ratios of arsenate (AsV):total dissolved arsenic (As). Based on qPCR estimates of bacterial and archaeal 16S rRNA gene abundance, aioA-harboring organisms comprised as much as ~15 % of the total community. Phylogenetically, the major aioA sequences (270 total) in the acidic hot springs (pH 3.3-4.4) were affiliated with Aquificales and Rhizobiales, while those in neutral or alkaline springs (pH 6.6-9.1) were inferred to be primarily bacteria related to Thermales and Burkholderiales. Interestingly, aioA abundance at one site greatly exceeded bacterial 16S rRNA gene abundance, suggesting these aioA genes were archaeal even though phylogenetically these aioA sequences were most similar to the Aquificales. In summary, this study described novel aioA sequences in geothermal features geographically far removed from those in the heavily studied Yellowstone geothermal complex. [ABSTRACT FROM AUTHOR]

Terrestrial hot springs have been suggested to harbor diverse diazotrophic lineages by using DNA-based nifH gene phylogenetic analysis. However, only a small amount of diazotrophs were ever confirmed to perform nitrogen fixation. In order to explore the compositions of active diazotrophic populations in hot springs, the in situ expression and diversity of nifH and 16S rRNA genes were investigated in the sediments of hot springs (pH 4.3-9.1; temperature 34-84°C) in Tengchong, China, by using high-throughput sequencing. The results showed that active diazotrophs were diverse in the studied Tengchong hot springs. The main active diazotrophs in high-temperature hot springs were affiliated with Aquificae , while those in low-temperature hot springs belonged to Cyanobacteria and Nitrospirae . Such dominance of Aquificae and Nitrospirae of diazotrophs has not been reported in other ecosystems. This suggests that hot springs may harbor unique active diazotrophs in comparison with other type of ecosystems. Furthermore, there were significant differences in the phylogenetic lineages of diazotrophs between hot springs of Tengchong and other regions, indicating that diazotrophs have geographical distribution patterns. Statistical analysis suggests that the expression and distribution of nifH gene were influenced by temperature and concentrations of ammonia and sulfur seem in Tengchong hot springs. These findings avail us to understand element cycling mediated by diazotrophs in hot spring ecosystems., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Song, Wang, Liang, Zhou, Pei, Jiang and Li.)