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Geology and Geochemistry of K-feldspar Veins in Lamprophyre at the Zhenyuan Gold Deposit,Yunnan,Southwest China:Implications for Gold Mineralization
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作者 ZHANG Huichao CHAI Peng +2 位作者 ZHANG Hongrui ZHOU Limin HOU Zengqian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第1期104-116,共13页
Lamprophyres typically appear in hydrothermal gold deposits.The relationship between lamprophyres and gold deposits is investigated widely.Some researchers suggest that the emplacement of lamprophyres triggers gold mi... Lamprophyres typically appear in hydrothermal gold deposits.The relationship between lamprophyres and gold deposits is investigated widely.Some researchers suggest that the emplacement of lamprophyres triggers gold mineralization,whereas others hypothesize that the formation of lamprophyres increases the fertility of mantle sources and ore-forming fluids.K-feldspar veins,with ages between those of lamprophyres and gold deposits,appear in lamprophyres in Zhenyuan.Therefore,K-feldspar veins are ideal for investigating the relationship between lamprophyres and gold deposits.Phlogopite in K-feldspar veins has lower Mg#,Ni,and Cr contents and higher TiO2,Li,Ba,Sr,Sc,Zr,Nb,and Cs contents than phlogopite in lamprophyres.The in-situ Sr isotopic values of apatites(0.7063–0.7066)in K-feldspar veins are within the range for apatites(0.7064–0.7078)from lamprophyres.High large-ion lithophile element concentrations and low Nb and Ta concentrations in phlogopite from lamprophyres,in addition to high(87Sr/86Sr)i values of apatite(0.7064–0.7078),indicate that the magma parental to these phlogopite and apatite crystals is derived from an enriched mantle.Kfeldspar veins are genetically correlated with lamprophyres,whereas sulfide mineral assemblage and trace element compositions of pyrite in K-feldspar veins suggest that K-feldspar veins in lamprophyres are not directly related to gold mineralization of the Zhenyuan deposit. 展开更多
关键词 LAMPROPHYRE K-feldspar vein apatite Sr isotope gold Zhenyuan deposit yunnan
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A Brief Discussion on the Development of the Silk-Weaving Industry Along the “Southern Silk Road” in Yunnan
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作者 Lin Kaiqiang 《Contemporary Social Sciences》 2024年第1期18-33,共16页
Ancient Yunnan was one of the most significant regions along China’s ancient“Southern Silk Road.”During the Nanzhao period(738–902)of the late Tang Dynasty,Yunnan’s silk-weaving industry underwent a qualitative l... Ancient Yunnan was one of the most significant regions along China’s ancient“Southern Silk Road.”During the Nanzhao period(738–902)of the late Tang Dynasty,Yunnan’s silk-weaving industry underwent a qualitative leap as skilled silk craftsmen from the Bashu area migrated to Yunnan and introduced mulberry planting,silkworm breeding,and advanced silk-weaving techniques from Sichuan to the region.Consequently,people in Yunnan gradually acquired expertise in brocade weaving and embroidery.Many even mastered complex silk-weaving techniques.The development and progress of the silk-weaving industry in the ancient Yunnan region were intricately linked to the economic function and value of silk as both a commodity and currency along the“Southern Silk Road.”The local government in ancient Yunnan was greatly motivated by the economic interests brought by the development of silk-related industries and recognized the significance of developing the local silk industry.They even initiated a campaign to capture skilled silk craftsmen from Sichuan,aiming to foster the growth of the silk-weaving industry in Yunnan.After years of dedicated efforts from the local government in ancient Yunnan,the region emerged as a significant hub for silk production along China’s ancient“Southern Silk Road.”Despite the devastation caused by the wars in other parts of the country,Yunnan’s silk industry continued to thrive and provide ample silk products to sustain trade along this renowned route.In the contemporary era,amidst the decline of the silk-weaving industry in eastern China,Yunnan has proposed an industrial development strategy known as“relocating the silk-weaving industry from east to west.”This involves introducing advanced silk production techniques from the eastern regions into Yunnan to enhance and enrich its local silk industry,thereby establishing it as a traditional national sector and securing a competitive position within the global silk market.The historical experience of Yunnan’s silk industry demonstrated that economic development opportunities can only be seized through proactive endeavors rather than passive anticipation.The modern Yunnan silk industry,which upholds its historical traditions,continues to actively engage in international high-end technical cooperation,thus ensuring the enduring vitality of the ancient“Southern Silk Road.” 展开更多
关键词 Southern Silk Road Bashu area yunnan silk-weaving technique
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Epidemiological survey of cystic echinococcosis in southwest China:From the Qinghai-Tibet plateau to the area of Yunnan
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作者 Jin-Rong Zi Dan Xiao +8 位作者 Jia Peng Fang-Wei Wu Jian-Xiong Li Xin-Liu Yan Zheng-Qing Wang Xuan Cai Qian Xu Ben-Fu Li Ya-Ming Yang 《World Journal of Hepatology》 2024年第2期229-240,共12页
BACKGROUND Echinococcosis is prevalent in 9 provinces in Western and Northern China.An epidemiological survey of echinococcosis in 2012 and 2016 showed cases of echinococcosis in Yunnan Province.AIM To understand the ... BACKGROUND Echinococcosis is prevalent in 9 provinces in Western and Northern China.An epidemiological survey of echinococcosis in 2012 and 2016 showed cases of echinococcosis in Yunnan Province.AIM To understand the spatial distribution and epidemiological characteristics of echinococcosis in Yunnan for the prevention and control of echinococcosis and to reduce the risk of infection in Yunnan Province.METHODS Based on the China Information System for Disease Control and Prevention(CISDCP),echinococcosis cases reported from 36 hospitals and 34 Centers for Disease Control were investigated and epidemiologically analyzed from 2021 to 2022.The exclusion criteria included suspected cases,same case only counted once and cases not from Yunnan.A total of 705 cases were investigated,of which 397 cases were suitable for statistical analysis.In these 397 cases,epidemiological investigation was tracked in 187 cases.All data were inputted using double entry in the Excel database,with error correction by double-entry comparison.The data on echinococcosis cases in Yunnan Province were analyzed by ArcGIS 10.1 software to generate a density map of echinococcosis distribution.All statistical analyses were conducted using SPSS 17.0,including the chi-square test,linear regression test and logistic univariate and multivariate regression analyses.RESULTS A total of 397 cases were found in 89 counties in Yunnan Province.The number of cases in the top three prefectures were Dali(38.1%),Diqing(10.1%),and Kunming(8.3%),and the top five counties were Jianchuan(9.1%),Shangri La(8.3%),Eryuan(7.6%),Heqing(6.9%),and Dali Districts(5.0%).There were significant differences between the different areas.The case reporting rate by CISDCP(33.8%)was low;the first case was reported by CISDCP in 2002,and the highest number of cases was 50(2017).Confirmed and clinical cases accounted for 62.5%and 37.5%,respectively.However,90.9%of the cases of hydatid disease were reported by the hospital system,and only 9.1%of the cases of hydatid disease were found in the community through active screening.The difference between the two methods of case detection was statistically significant.Most of the cases of echinococcosis were found in farmers/herdsmen(75.1%)and students(9.1%).In addition,Han(43.6%)and Bai(26.2%)had a higher incidence of infection than other nationalities,and the liver(87.7%)and lung(6.8%)were the most common sites of cyst formation.Among the analyzed cases,187 were epidemiologically analyzed and the clinical symptoms were not obvious in the early stage in 47.1%of cases.The results of logistic regression analysis showed that the age group,education level,presence of dogs in the family(either previously or currently),and handwashing(occasionally or not)were factors related to echinococcosis infection.55.6%of cases were in endemic areas,and 44.4%of cases were in non-endemic areas.Among 83 cases in non-endemic areas,only 4 cases had been to endemic areas and had a history of living,working,travelling,or hunting in echinococcosis epidemic areas.CONCLUSION Cases of echinococcosis were reported throughout the entire Yunnan province,with the majority distributed in Western Yunnan,suggesting that echinococcosis control should be strengthened in this area.We suggest that an epidemiological investigation should be carried out in the future,based on the clues from newly discovered cases in hospitals or from the CISDCP.The newly discovered cases in the hospital provided clues to comprehensively determine the location of cases and where epidemic spot investigation should be conducted. 展开更多
关键词 ECHINOCOCCOSIS CASES Epidemiological analysis yunnan province
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Reanalysis on the Spectral Characteristics and Materials of Jade Jue Unearthed from Lijiashan Ancient Tomb in Yunnan Province, China
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作者 Ting Fang Jifu Liu Mingxing Yang 《宝石和宝石学杂志(中英文)》 CAS 2024年第2期48-55,共8页
Jade ware Jue is one of the most fashionable ornament in ancient China from the Neolithic Age to the Han Dynasty.In this study,the remnants of jade ware Jue,from Lijiashan ancient tomb group have been tested and analy... Jade ware Jue is one of the most fashionable ornament in ancient China from the Neolithic Age to the Han Dynasty.In this study,the remnants of jade ware Jue,from Lijiashan ancient tomb group have been tested and analyzed respectively.The samples through a light etch surface showing glass luster and those with a severe etch surface showing earthen luster.With the aid of X-ray fluorescence Spectrometer(X-ray Fluorescence)test and X-ray diffraction(XRD)detection,the results show that tremolite is not the main mineral of the sample.The main components of the tested samples with light erosion are antigorite and talc,although the main components of the samples with severe erosion are calcite containing calcium carbonate barium.Furthermore,the research on jade ware Jue in Yunnan culture has not only contributed to our further understanding of the jade objects from Yunnan culture and the variety of jade material located in the Yunnan Province.It also provides a basis for the trace of the history and culture through the distribution and evolution of burial hierarchy laws.At the same time,the microscopic observation of the tested samples manifested a residual trace of“string”at the perforation,which has played a critical role in restoring the wearing of jade ware Jue from the tombs of the ancient Yunnan State and the handicraft skills at that time. 展开更多
关键词 Dian culture jade Jue corroded ancient jade XRD erosion mechanism yunnan China
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Latest Neogene Paleoclimate Variation in Yunnan,Southwest China,Revealed by Fossil Leaf Physiognomy
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作者 DAI Jing CHEN Weizhao +1 位作者 HUANG Liang ZHANG Yi’nan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第4期1268-1281,共14页
Yunnan Province,located in the southeastern margin of the Tibetan Plateau,can provide important information on how climate change was influenced by global cooling.However,its variation patterns in temperature and prec... Yunnan Province,located in the southeastern margin of the Tibetan Plateau,can provide important information on how climate change was influenced by global cooling.However,its variation patterns in temperature and precipitation during the latest Neogene are not well-understood.Based on the 357 specimens assigned to 31 morphotypes of plant fossils from the upper Pliocene Ciying Formation in Yiliang County,Yunnan Province,Southwest China,paleoclimate was estimated by Leaf Margin Analysis and Climate Leaf Analysis Multivariate Program.Compared to the present climate,the mean annual temperature and coldest month temperature have not changed significantly since the late Pliocene,whereas the warmest month temperature has decreased significantly.All precipitation-related parameters have decreased,particularly winter precipitation.Combined with the climatic data of the same period in other areas of Yunnan,the western and eastern Yunnan has shown a similar pattern in temperature variation since the late Pliocene except for central Yunnan;whereas the variation in precipitation does not follow a common law except for a consistent decrease in winter precipitation.Our study reinforced the fact that under the background of global cooling and intensified monsoon systems,different areas of Yunnan exhibit different climatic responses to these changes because of their topographic heterogeneities. 展开更多
关键词 plant fossil paleoclimate reconstruction monsoon PLIOCENE yunnan
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New and interesting diatoms from the Shimen Wetwalls,Yunnan Province,China.Ⅱ.The diatom genus Nupela Vyverman&Compère(Bacillariophyceae)
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作者 Qi LIU Xi LUO +1 位作者 Shulian XIE John Patrick KOCIOLEK 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第1期327-341,共15页
We detailed the valve morphology of five new species of diatom genus Nupela from wetwall communities in Yunnan Province,China,with light and scanning electron microscope.The five new species demonstrate great variabil... We detailed the valve morphology of five new species of diatom genus Nupela from wetwall communities in Yunnan Province,China,with light and scanning electron microscope.The five new species demonstrate great variability within the genus,as three of them are biraphid and two are monoraphid.In addition,variation was noted in the structure of internal proximal raphe ends,with some species having anchor-shaped ends and other species have hooked ends.The genus Nupela has grown considerably in 30years since it was first proposed,going from a monotypic genus to over 85 taxa.Diagnosis of the genus is based on the presence of an external covering over the areolae.We discussed the systematic placement of Nupela within the naviculoid diatoms.Yunnan Province appears to harbor many endemic diatom taxa,and many regions of the province have yet to be studied. 展开更多
关键词 Nupela scanning electron microscope(SEM) yunnan new species morphology China BACILLARIOPHYCEAE
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Inferring Human-elephant Coexistence Based on Characteristics of Human-elephant Interactions in Nangunhe of Yunnan,China
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作者 WANG Jiahui CHEN Ying +2 位作者 SUN Yakuan LYU Zhuoluo SHI Kun 《Chinese Geographical Science》 SCIE CSCD 2023年第2期363-376,共14页
Human-wildlife conflict(HWC)negatively impacts both humans and wildlife.Attitudes of local residents have been critical in promoting wildlife conservation.It is therefore necessary to understand the characteristics of... Human-wildlife conflict(HWC)negatively impacts both humans and wildlife.Attitudes of local residents have been critical in promoting wildlife conservation.It is therefore necessary to understand the characteristics of HWC and identify influential factors on attitudes towards conservation to implement conservation strategies efficiently.This research focused on features of human-elephant interactions,while attitudes and values regarding the small population of Asian elephants(Elephas maximus)in Nangunhe National Nature Reserve(NNR),Yunnan,China.The total of 327 valid questionnaires were gathered around the area where Asian elephants were distributed.Logistic regression models were employed to analyze the correlations among five predictor variables(‘Area’,‘Family size’,‘Annual income’,‘Quantity of family members in non-primary industries’and‘Experiencing loss or not’)and three response variables(‘Attitude towards elephants’,‘Perception of the values of elephants’and‘Attitude towards tourism development’).The study area was densely forested with tea plants,rubber trees,corns and sugarcane.There,25.99%of respondents reported the experience of human-elephant conflict(HEC),with crop raiding and cash crop damages being the major conflict types.To demonstrate respect for elephants and to mitigate HEC,a unique custom called‘Giving tribute to elephants’was developed long ago.Respondents’township with an official annual festival of‘Giving Tribute to Elephants’(odds ratio(OR)=2.75,P=1.73×10^(-6))and higher annual income(OR=2.09,P=5.45×10^(-5))significantly contributed to forming a more positive attitude towards elephants,whereas HEC itself have contributed to a more negative attitude(OR=0.50,P=3.29×10^(-3)).Therefore,we propose that:1)reducing human-elephant conflict by testing multiple mitigation measures and adopting the most effective one of them;2)enhancing local livelihoods through the development of ecological products and ecotourism;and 3)preserving and developing the Wa culture in this region.The study area deserves more attention and further research to explore and obtain endorsement from the public to achieve coexistence between human and wildlife. 展开更多
关键词 Asian elephant(Elephas maximus) Wa people human-elephant conflict COEXISTENCE Nangunhe National Nature Reserve yunnan China
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A New Species of the Genus Hebius Thompson,1913(Serpentes:Natricidae)from Yunnan,China
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作者 Shun MA Shengchao SHI +1 位作者 Budian AYI Jianping JIANG 《Asian Herpetological Research》 SCIE CSCD 2023年第3期212-226,共15页
A new keelback snake of the genus Hebius,H.jingdongensis sp.nov.,is reported from Jingdong in Yunnan,China based on a combination of molecular and morphological evidence.Although closest to H.khasiensis and H.boulenge... A new keelback snake of the genus Hebius,H.jingdongensis sp.nov.,is reported from Jingdong in Yunnan,China based on a combination of molecular and morphological evidence.Although closest to H.khasiensis and H.boulengeri phylogenetically,this new species is genetically distinct amongst congeners with the mitochondrial Cyt b uncorrected p-distance ranging from 9.5%(vs.H.octolineatus)to 14.8%(vs.H.andreae).In addition,this new species can be distinguished from its congeners by a combination of the following morphological characters:(1)body cylindrical,tail relatively short,TaL/TL 0.235–0.243;(2)dorsal scale rows 19-19-17;(3)ventrals 163–166,cloacal plate divided,subcaudals 71–74 pairs;(4)supralabials 8,the first two contact with the nasals;(5)infralabials 9 or 10,preocular 1,postoculars 3;(6)body dorsum sandy beige with the sides yellowish-brown decorated with two brick-red stripes on the dorsolateral scale rows in life;(7)sutures between the labials brick-red in life and taupe in preservative;(8)ventral light yellow with the outer part of each scale brick-red in life;(9)ventrolateral stripes present. 展开更多
关键词 Hebius jingdongensis sp.nov. molecular phylogeny morphology taxonomy yunnan province
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Geological characterization and exploration potential of shale gas in the Carboniferous Jiusi Formation,northern Guizhou and Yunnan provinces,SW China
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作者 Weiming Feng Rong Li +3 位作者 Zhan Zhao Qian Yu Wei Liu Junfeng Cao 《Energy Geoscience》 2023年第3期169-181,共13页
Dark mudstones and shales of the Carboniferous Jiusi Formation are widely developed in northern Guizhou and Yunnan provinces, SW China. However, the distribution, reservoir characterization, and exploration potential ... Dark mudstones and shales of the Carboniferous Jiusi Formation are widely developed in northern Guizhou and Yunnan provinces, SW China. However, the distribution, reservoir characterization, and exploration potential of organic-rich shales in this area are yet to be quantified, thus limiting the prospect of shale gas in this area. This study investigates the basic geological conditions of Jiusi shale gas, using core data, well-logs, and some other test data, obtaining the following results. The organic-rich shales are mainly composed of deltaic-to-shallow-shelf deposits, with thickness ranging from 0 to 450 m, and above 350 m around the subsidence center. The organic matter is mainly type Ⅱ kerogen with TOC content of mostly 1%–2%, indicating a moderate maturity. The argillaceous shale reservoirs are indicative of strong heterogeneity, high clay minerals content, low porosity, low permeability, high specific surface area, and relatively developed secondary porosity. The gas-log anomaly intervals obtained from the survey wells have a cumulative thickness that is apparently greater than 200 m, and a few shale intervals showing high desorbed and adsorbed gas contents. Due to complex structures in the study area, conditions responsible for shale gas occurrence and trapping are generally moderate. However, areas having wide and gentle folds with moderate depth of burial reveals relatively favorable conditions of hydrocarbon traps. In contrast with typical marine-continental transitional shales, the Jiusi shale have better geological conditions for shale gas preservation. The analysis of the geological framework and hydrocarbon potential of Carboniferous Jiusi Formation provide more insight for the exploration of Carboniferous shale gas in southern China. 展开更多
关键词 Marine-continental tansitional fades 0rganic-nich shale Shale gas Exploration potential CARBONIFEROUS Northem border area between Guizhou and yunnan China
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Earthquake focal mechanisms and stress field in Sichuan-Yunnan area determined using P wave polarity and short period P and S waveform data 被引量:1
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作者 陈天长 郑斯华 ZHENG Si-hua 《Acta Seismologica Sinica(English Edition)》 CSCD 2001年第4期466-470,共5页
关键词 Sichuan-yunnan area FOCAL mechanism stress field 分类号:P315.3+3 文献标识码:A 文章编号:1000-9116(2001)04-0466-05 Based on waveform data several methods to determine FOCAL mechanisms of SMALL EARTHQUAKES were developed since 1980. Kisslinger (1980) and Julian Foulger (1996) proposed an approach to determine solution by using amplitude ratio of P and S wave. Schwartz (1995) devised a method to determine solutions by the use of polarity DATA and amplitudes of seismogram envelopes. Amplitudes of short period seismic waves propagating in an inhomogene-ous medium ARE sensitive to the variation in velocity and Q structure. Nakamura et al (1999) took medium inhomo-geneity into account in determining FOCAL mechanisms of SMALL EARTHQUAKES using waveform data. If the locations of SMALL EARTHQUAKES ARE concentrated in a SMALL region we can assume that the raypaths from the events to a given station ARE almost the same. So P and S wave attenuations ARE independent of event locations. In this case it is con-venient to determine FOCAL mechanisms of these events by using short period P and S wave dataj. FOCAL mechanism solutions of SMALL EARTHQUAKES in 5 regions i.e. Rongchang Mabian-Muchuan Ya'an Baoxing and Mianzhu which ARE covered by the Chengdu Telemetered Network ARE obtained by analyzing the P polarity and short body wave amplitude DATA recorded in the network since 1992. According to the method proposed by Gephart and Forsyth (1984) based on well determined FOCAL mechanism solutions in 15 sub-zones of Sichuan and yunnan area three principal stress tensors s1 s2 and s3 instead of averages of P B and T axis of the solutions ARE determined to represent the regional stress field distribution.……
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Discuss on the Countermeasures and Measures for the Development of Yunnan-style Gardens in the Southwestern Frontier of China——A Case Study on Honghe Hani-Yi Autonomous Prefecture
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作者 Hui LIANG Qizhi LI +5 位作者 Jiang ZHU Xiuping CHEN Zixi LIANG Li QUAN Guiying YANG Yushu HUANG 《Agricultural Biotechnology》 CAS 2021年第5期106-114,共9页
Yunnan gardening in the southern extension of the Himalayas has its specificity.Because of extremely rich elements,the natural endowment has objectively"casted"a series of vivid"Chinese ink paintings&qu... Yunnan gardening in the southern extension of the Himalayas has its specificity.Because of extremely rich elements,the natural endowment has objectively"casted"a series of vivid"Chinese ink paintings",that is to say you can"move and then see a new scene,turn and then face a new view".Yunnan-style gardens,which imply truth in"paintings"by intricately carving and constantly improve the connotation and extension creation process,are not only an economic phenomenon,but also a cultural category and the crystallization of the collective wisdom of all ethnic groups in Yunnan.The"Yunnan-style gardens"system is being constructed.This paper traced the growth process and proposed development countermeasures and measures based on the analysis of Yunnan s resource endowment. 展开更多
关键词 yunnan garden yunnan-style garden Scenic spot Landscape garden Agricultural industrialization urban greening
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The coda attenuation of the Yao'an area in Yunnan Province 被引量:59
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作者 李白基 秦嘉政 +1 位作者 钱晓东 叶建庆 《地震学报》 CSCD 北大核心 2004年第1期47-52,共6页
2000年1月15日云南姚安发生了6.5级地震.震后围绕震中区架设了一个由6套拾震器-记录仪组成的临时数字地震台网.在所记录的余震中,有402次余震有较精确的定位.依照Sato的单散射模型分析观测的尾波短记录,获得了姚安地区地壳的尾波... 2000年1月15日云南姚安发生了6.5级地震.震后围绕震中区架设了一个由6套拾震器-记录仪组成的临时数字地震台网.在所记录的余震中,有402次余震有较精确的定位.依照Sato的单散射模型分析观测的尾波短记录,获得了姚安地区地壳的尾波平均品质因子Qc(f)=49f^0.95,f=1.5~20.0Hz,具有高构造活动性区域的衰减特征. 展开更多
关键词 Sato单散射模型 尾波衰减 地震定位 地震波 数字地震台网
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Tectonic Evolution of the Palaeo——Tethys in Changning——Menglian Belt and Adjacent Regions,Western Yunnan 被引量:22
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作者 Liu Benpei Feng Qinglai Fang NianqiaoChina University of Geosciences , Beijing 100083 《Journal of Earth Science》 SCIE CAS CSCD 1991年第1期21-31,共11页
The Changning-Menglian belt,located between theBaoshan-Gengma massif and the Simao-Lincangmassif in Western Yunnan,preserves the complete recordof a suture zone and the most continuous record of deepwater sedimentatio... The Changning-Menglian belt,located between theBaoshan-Gengma massif and the Simao-Lincangmassif in Western Yunnan,preserves the complete recordof a suture zone and the most continuous record of deepwater sedimentation,representing the main branch of thePalaeo-Tethys polyisland ocean in the Hercynian-Indo-sinian stage.This belt could be further subdivided into threetectono-lithofacies zones.In the east zone,terrigenouselastics,argillaceous,marl-argillaceous and silicate sediments lie on the metamorphosed Early Palaeozoic basement in concealed unconformity,representing deep watersediments on a passive continental margin.The centralzone,although the basement rocks are absent fromoutcropping here,includes a contemporary complexof various sedimentary types,among them one type is ofdeep ocean sediments represented by radiolarian beddedchert,appearing from at least early Early Devonian tothe Middle Triassic.Another type includes purecarbonates of the Early Carboniferous to the LatePermian,a type of shallow 展开更多
关键词 Palaeo - TETHYS TECTONIC evolution Changning - Menglian BELT Lancangjiang BELT Western yunnan.
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Source mechanism of small-moderate earthquakes and tectonic stress field in Yunnan Province 被引量:25
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作者 WU Jian-ping(吴建平) +3 位作者 MING Yue-hong(明跃红) WANG Chun-yong(王椿镛) 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第5期509-517,共9页
In the paper, source mechanisms of 33 small-moderate earthquakes occurred in Yunnan are determined by modeling of regional waveforms from Yunnan digital seismic network. The result shows that most earthquakes occurred... In the paper, source mechanisms of 33 small-moderate earthquakes occurred in Yunnan are determined by modeling of regional waveforms from Yunnan digital seismic network. The result shows that most earthquakes occurred within or near the Chuandian rhombic block have strike-slip mechanism. The orientations of maximum compressive stresses obtained from source mechanism are changed from NNW-SSN to NS in the areas from north to south of the block, and tensile stresses are mainly in ENE-WSW or NE-SE. In the eastern Tibetan Plateau, the orientations of maximum compressive stress radiate toward outside from the plateau, and the tensile stress orientations mostly parallel to arc structures. Near 28°N the orientations of both maximum compressive stress and tensile stress changed greatly, and the boundary seems to correspond to the southwestern extended line of Longmenshan fault. Outside of the Chuandian rhombic block, the orientations of P and T axes are some different from those within the block. The comparison shows that the source mechanism of small-moderate events presented in the paper is consistence with that of moderate-strong earthquakes determined by Harvard University, which means the source mechanism of small-moderate events can be used to study the tectonic stress field in this region. 展开更多
关键词 SOURCE mechanism small-moderate EARTHQUAKES STRESS field yunnan
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Study on distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background 被引量:30
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作者 韩渭宾 蒋国芳 《地震学报》 CSCD 北大核心 2004年第2期211-222,共12页
In the paper, the distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background, especially the relation to Sichuan-Yunnan and Sichuan-Qinghai crustal blocks have b... In the paper, the distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background, especially the relation to Sichuan-Yunnan and Sichuan-Qinghai crustal blocks have been studied. The main results are: a) Strong earthquakes in Sichuan-Yunnan area distribute mainly in Sichuan-Yunnan and Sichuan-Qinghai crustal blocks; b) Most of strong earthquakes of the two blocks distribute mainly along their boundary faults; c) A few strong earthquakes are not obviously related to active faults. It shows that the relation between strong earthquakes and geological tectonics can be very complex; d) There is a certain correlativity for seismic activities among boundary faults of the two blocks, but they have different features; e) There are some anomalous changes of velocity structures in the deep crust of boundary faults of the two blocks. Many boundary faults, especially Longmenshan fault, cut obviously the Moho discontinuity. The Xianshuihe fault, a typical strike-slip fault, has no obvious indication of cutting the Moho discontinuity, but has distinct low-velocity zone in different depths. 展开更多
关键词 川滇地区 地震活动性 地壳块体 深部结构 强震活动 分布特征
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Seismic tomography of Yunnan region using short-period surface wave phase velocity 被引量:9
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作者 HE Zhengqin(何正勤) +3 位作者 SU Wei(苏伟) YE Tai-lan(叶太兰) 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第6期642-650,共9页
The data of short-period (1~18 s) surface waves recorded by 23 stations belonging to the digital seismic network of Yunnan Province of China are used in this paper. From these data, the dispersion curves of phase vel... The data of short-period (1~18 s) surface waves recorded by 23 stations belonging to the digital seismic network of Yunnan Province of China are used in this paper. From these data, the dispersion curves of phase velocities of the fundamental mode Rayleigh wave along 209 paths are determined by using the two-station narrowband filtering cross-correlation method.Adopting tomography method, the distribution maps of phase velocities at various periods in Yunnan region are inverted. The maps of phase velocities on profiles along 24°N, 25°N, 26°N, 27°N and 100.5°E and the distribution maps of phase velocities at 3 periods in the study region are given. The results show that the phase velocity distribution in Yunnan region has strong variations in horizontal direction, and the phase velocity distribution in short-period range is closely related to the thickness of sedimentary layers in the shallow crust. The phase velocity in southern part of the Sichuan-Yunnan rhombic block encircled by the Honghe fault and Xiaojiang fault is obviously lower than that in surrounding areas. The epicentral locations of strong earthquakes in Yunnan region are mainly distributed in transitional zones between low and high phase velocities. 展开更多
关键词 yunnan region phase VELOCITY of RAYLEIGH waves tomography middle and upper CRUST VELOCITY structure
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Regional stress field in Yunnan revealed by the focal mechanisms of moderate and small earthquakes 被引量:16
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作者 JianHui Tian Yan Luo Li Zhao 《Earth and Planetary Physics》 CSCD 2019年第3期243-252,共10页
We determined focal mechanism solutions of 627 earthquakes of magnitude M ≥ 3.0 in Yunnan from January 2008 to May 2018 by using broadband waveforms recorded by 287 permanent and temporary regional stations. The resu... We determined focal mechanism solutions of 627 earthquakes of magnitude M ≥ 3.0 in Yunnan from January 2008 to May 2018 by using broadband waveforms recorded by 287 permanent and temporary regional stations. The results clearly revealed predominantly strike-slip faulting characteristics for earthquakes in Yunnan, with focal depths concentrated in the top 10 km of the crust. The earthquake mechanisms obtained were combined with the global centroid moment tensor solutions of 80 additional earthquakes from 1976 to 2016 to invert for the regional variations of stress field orientation by using a damped regional-scale stress inversion scheme.Results of the stress field inversion confirmed that the Yunnan region is under a strike–slip stress regime, with both maximum and minimum stress axes being nearly horizontal. The maximum compressional axes are primarily oriented in a northwest-southeast direction, and they experience a clockwise rotation from north to south, whereas the maximum extensional axes are oriented largely northeast-southwest. The maximum compressional axes are in line with the global positioning system–inferred horizontal velocity field and the southeastward escape of the Sichuan–Yunnan Rhombic Block, whereas the maximum extensional axes are consistent with anisotropy derived from SKS splitting. Against the strike–slip background, normal faulting stress regimes can be seen in the Tengchong volcanic area as well as in other areas with complex crisscrossing fault zones. 展开更多
关键词 earthquake FOCAL mechanism stress field INVERSION PRINCIPLE stresses yunnan region
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Researches on Plants from the Lower Devonian Xujiachong Formation in the Qujing District, Eastern Yunnan 被引量:7
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作者 王德明 郝守刚 刘振锋 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2002年第4期393-407,共15页
Fossil plants Hedeia sinica Hao et Gensel 1998, Huia gracilis Wang et Hao 2001 andGuangnania cuneata Wang et Hao are described from the Lower Devonian Xujiachong Formation, the Qujingdistrict, eastern Yunnan, China. T... Fossil plants Hedeia sinica Hao et Gensel 1998, Huia gracilis Wang et Hao 2001 andGuangnania cuneata Wang et Hao are described from the Lower Devonian Xujiachong Formation, the Qujingdistrict, eastern Yunnan, China. They contribute to our knowledge of the flora in this district. Based on theoccurrence of common plants (Hedeia, Huia, Guangnania and Zosterophyllum australianum) and their horizons,it is proved for the first time that the mid-lower assemblage of the Xujiachong flora is comparable with theEarly Devonian ((late) Pragian) Posongchong flora of southeastern Yunnan and the upper Baragwanathia floraof Australia. In view of this fact and the stratigraphic sequence, the mid-lower part of the Xujiachong Formationis considered to be of (late) Pragian age. Through comprehensive analyses of plant, bivalve and fishassemblages and the lithology, the upper part of the Xujiachong Formation is dated to be of early Emsian age.The Xujiachong flora belonged to the northeastern Gondwana palaeophytogeographic unit during the EarlyDevonian. The early Emsian assemblage of this flora inherited the characters of the Posongchong flora and alsoexhibited the endemic elements. Belonging to different phytogeographic units, the Xujiachong and Posongchongfloras differ from the coeval flora of the Laurussian palaeocontinent. The Xujiachong flora is comparativelysimple in composition, while the Posongchong flora has abundant and highly diversified endemics. Thedisparity between them has resulted from the different environments. 展开更多
关键词 Fossil plants Xujiachong Formation EASTERN yunnan (late) Pragian-early Emsian similarity between floras phytogeography and environment
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Seismic tomography of Yunnan region using short-period surface wave phase velocity 被引量:13
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作者 何正勤 苏伟 叶太兰 《地震学报》 CSCD 北大核心 2004年第6期583-590,共8页
利用云南数字地震台网23个台站记录的短周期(1~18s)面波资料,用双台窄带通滤波互相关方法,测定了在209条路径上的基阶瑞利波相速度频散曲线,并通过层析成像反演得到各周期的相速度分布图象.给出了沿24°N,25°N,26°... 利用云南数字地震台网23个台站记录的短周期(1~18s)面波资料,用双台窄带通滤波互相关方法,测定了在209条路径上的基阶瑞利波相速度频散曲线,并通过层析成像反演得到各周期的相速度分布图象.给出了沿24°N,25°N,26°N及27°N和100.5°E的相速度频散剖面图.结果表明:云南地区的相速度分布图象具有强烈的横向变化,短周期段的相速度分布与沉积层厚度密切相关,中甸、丽江东部区域在约25km深度存在着明显的低速层,而畹町、云县、思茅一带在该深度范围是一明显的大面积高速区域.小江断裂与红河断裂围成的川滇菱形块体南段为低相速度区域.云南地区强震震中位置主要分布在相速度高速与低速过渡的区域. 展开更多
关键词 云南地区 瑞利波相速度 层析成像 地壳中上部 速度结构
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Deep medium environment of strong earthquakes occurrence in Yunnan region 被引量:6
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作者 苏有锦 刘祖荫 +2 位作者 蔡民军 张俊伟 李忠华 《Acta Seismologica Sinica(English Edition)》 EI CSCD 1999年第3期345-356,共12页
The deep structure background of earth medium for strong earthquakes ccurrence in Yunnan area is discussed inthis paper, by using the results on the study of the velocity structure, elect fieal conductivity stricture,... The deep structure background of earth medium for strong earthquakes ccurrence in Yunnan area is discussed inthis paper, by using the results on the study of the velocity structure, elect fieal conductivity stricture, geothermalstructure in the crust and upper mantle in Yunnan area. The results show that the occurrence of strong earthquakes in Yunnan region is obviously related to the deep medium and tectonic environment such as the existenceof the high velocity zone in the upper crust, the low velocity zone or high electrical conductivity layer in themiddle crust, local uplift in the upper mantle, high geothermal activity and deep and large fault, etc. The large earthquakes could not take place at anywhere, they often occur at some regions which have a certainbackground in the deep medium structure. The activity of the earthquakes with magnitude of 5 or less is quite random,the occurrence of them have not the obvious background of the deep medium strUcture. 展开更多
关键词 yunnan region activity of strong EARTHQUAKES DEEP MEDIUM of earth SEISMOGENESIS
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