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2022yearNo.41volumeNo.8phase

  • Recognition and identification of spatial mineralization patterns
    LI Yuwei, LI Jingchao, WANG Chengxi
    A recent development in mineral exploration is the use of information technology to define the distribution of mineralization and prospecting targets using spatial data.With geological,geophysical,and geochemical map layers as input data,fuzzy clustering was used in this study to recognize spatial patterns on the GIS platform,and the mineralization patterns were identified by geological interpretation.Fuzzy clustering is a hybrid spatial pattern recognition method composed of c-means clustering,neural network and fuzzy sets.Being an unsupervised classifier,it uses fuzzy membership as an uncertain measurement of the spatial pattern recognition.In the complex distribution environment where diverse deposit types coexist and intersect,different individualized mineralization patterns can be recognized and identified.This study illustrates the technique of fuzzy clustering spatial mineralization pattern recognition and identification,with successful results,using the 1:200 000 map of Ulanhot,Inner Mongolia as an example.
    2022  .  41(8):    1309-1321    [摘要](251)    [PDF](336)
  • Activity structure and crustal stability in Beijing-Tianjin-Hebei collaborative development zone
    WANG Huiqing, TAN Chengxuan, FENG Chengjun, QI Bangshen, WANG Jiming, YANG Weimin, ZHANG Chunshan, ZHANG Peng, MENG Jing, YANG Xiaoxiao, WANG Shiqiang, YI Bing, SUN Mingqian, MENG Huajun
    Beijing-Tianjin-Hebei Collaborative Development Zone(BTHCDZ)is one of the strategic development zones in eastern China,and is also the active tectonic region in North China.Based on its strong neotectonic activity,many active faults and frequent earthquakes,it is sure that there are potential geological safety hazards.Based on the results of the investigation and research on Zhangjiakou area,Xiong'an New Area and neighboring area,Beijing area and its key tectonic sites,and combined with the comprehensive analysis of the existing research results,the features of the geometry,kinematics and dynamics of the main active fracture and as well as the engineering geology and geohazards are systematicly analyzed in the BTHCDZ.And then the assessment of crustal stability based on the spatial analysis function of ArcGIS platform in the BTHCDZ has been completed.The results show that:There are Xingtai-Hejian-Tangshan and Shijiazhuang-Tongzhou two NNE-trending,and Zhangjiakou-Bohai one NWW-trending activity tectonic belts existed in the BTHCDZ,and within the three belts,there are 11 Holocene fractures,16 Late Pleistocene fractures and 23 major Quaternary fractures;The direction of the maximum horizontal principal stress of present tectonic stress field in the north and southeast regions of Hebei Province is near EW,while the southern section of the east edge of Taihangshan is NNE direction and the northern section is NW direction;The overall performance of NNE active fault belt is clockwise normal activity with SE tendency,while NWW active fault belt has obvious activity from Late Pleistocene,and the overall performance is anti-clockwise normal activity with SW tendency;The general crustal stability of the BTHCDZ is general good for the planning and construction of important towns and major projects,and the unstable zones and sub-unstable areas are mainly distributed in Xingtai,Tangshan,Yanhuai Basin and the Holocene active fault zone.The research results will provide geological support for the macro-development strategy of the BTHCDZ.
    2022  .  41(8):    1322-1341    [摘要](228)    [PDF](327)
  • Zircon U-Pb ages,geochemical characteristics and constraints on the Bangong-Nujiang Tethys Ocean subduction of Late Jurassic-Early Cretaceous intrusive rocks from Mami area, Tibet
    ZHAO Shouren, YUE Yunzhang, WU Zhe
    Large-scale Mesozoic igneous rocks distributed on the north and south sides of the Bangong-Nujiang suture zone are important in constraining the evolution of the Tethyan Ocean.This paper reports the zircon U-Pb age,major and trace geochemical characteristics of the felsic intrusive rocks in the Mami area,south of the Bangong-Nujiang suture zone.The 206Pb/238U weighted average ages of 146~145 Ma for the granitic porphyry and 140 Ma for the granitic amphibolite indicate that the intrusive rocks were emplaced during the Late Jurassic to Early Cretaceous.Both granitic porphyry and granodiorite show high content of SiO2(64.67%~77.45%),Al2O3 (12.59%~16.24%)and low MgO(0.19%~0.89%),which are weakly-strongly peraluminous calc-alkaline granite.These rocks are also enriched in large-ion lithophile elements(LILE)of Rb,K,and depletion in high field strength elements(HFSE)of Nb,Ta,Ti.The total amount of rare earth elements(REE)is low(∑REE=129×10-6~201×10-6),and the fractionation degree is high(LREE/HREE=2.06~9.18).The REE patterns show enrichment in light rare earth elements(LREEs)with negative Eu anomalies,which consistent with the REE distribution patterns of felsic magmatic rocks formed on the active continental margin.Comprehensive analysis shows that the Late Jurassic-Early Cretaceous felsic intrusive rocks in Mami mainly originated from the partial melting of ancient crustal materialand and underwent fractional crystallization during the magmatic evolutionary process.Theses intrusive rocks show the characteristics of volcanic arc-type,suggesting that they formed in the background of ocean subduction.Previous studies,in combination with regional data,show that Bangong-Nujiang Ocean underwent southward subduction during the Late Jurassic to Early Cretaceous,forming the Cuoqin-Shenzha tectonic-magmatic arc.It further confirmed the bidirectional subduction of the Bangong-Nujiang Tethyan Ocean during the Late Jurassic-Early Cretaceous period,which provides new lithological evidence for the tectonic evolution of the Tethyan Ocean.
    2022  .  41(8):    1342-1357    [摘要](241)    [PDF](313)
  • Zircon U-Pb age, petrogenesis and tectonic model of Miocene quartz monzonite in Zuozuoxiang area, Western Lhasa terrane
    ZHANG Bochuan, FAN Jianjun, LUO Anbo, LI Hang, SHEN Di, LIU Haiyong
    The Miocene magmatism is of great significance to distinguish the Cenozoic tectonic evolution of the Tibetan Plateau.In this paper,a new set of Miocene quartz monzonite has been redefined in Zuozuoxiang area,western Lhasa terrane.Zircon U-Pb dating shows that the age of quartz monzonite is 22.38±0.46 Ma.Whole rock geochemical test shows that quartz monzonite has high SiO2(65.87%~66.90%),K2O(6.19%~6.41%)contents,K2O/Na2O(1.7~1.8)ratios and low MgO(1.71%~1.76%)contents,belonging to potassic intermediate-acid rock.According to the high Mg#(56.5~57.8),Nb/Ta(16.0~16.4),Cr(46.0×10-6~48.9×10-6),Ni(32.6×10-6~34.8×10-6)and a large number of dark inclusions in the rocks,we believe that Miocene quartz monzonite from Zuozuoxiang area was formed by partial melting of thickened lower crust with the addition of mantle material.In addition,based on the results of uplift studies,we believe that the tearing of Indian plate is more suitable for the interpretation of Miocene potassic-ultrapotassic rocks in Lhasa terrane than the convective thinning of lithospheric mantle,the delamination of thickened lithosphere and the break-off of Indian plate.
    2022  .  41(8):    1358-1368    [摘要](218)    [PDF](297)
  • Age, petrogenesis and tectonic setting of bimodal volcanic rocks from Yeba Formation in Maizhoukunggar, southern Tibet
    SONG Yuhang, XIE Chaoming, YU Yunpeng, ZHU Lidong, HAO Yujie, YANG Chen
    The study of the Early Mesozoic magmatic rocks in the southern Tibetan Plateau is of great significance to the inversion of regional tectonic evolution.The volcanic rocks of the Yeba Formation in Early Jurassic are considered to be the early records of the subduction of the Neo-Tethys ocean.At present,there are still controversies about the tectonic setting of their formation.We selected the volcanic rocks of Yeba Formation in Maizhoukunggar county,southern Tibet,as the research objects.We present new zircon U-Pb isotopes and whole rock geochemical composition testing,discuss the implications for evolution of this region.The main lithology includes basalts(181.0±5.0 Ma,n=1)and rhyolites(181.4±4.4 Ma,MSWD=0.017,n=18),and they have bimodal volcanic characteristics.The basalts have high TiO2(1.62%~1.78%),P2O5(0.49%~0.51%)and Nb(10.18%~10.61%)concentrations,(La/Nb)PM<2,which are similar to the ENB.The Mg#s are between 54.9~57.3,enrichment of LREE and depletion of HREE.Rhyolites have highly SiO2 (79.25%~80.22%),Na2O(3.94%~4.26%)contents,Mg # values are 49.1~50.4,Th/Ce ratios are 0.1~0.15,Th/La ratios are 0.22~0.31,Nb/Ta ratios are 14.06~14.32,Sr/Y ratios are 4.15~4.82,and enrichment of LREE and LILE and depletion of HFSE.It is considered that the magma source area of basalts is mantle wedge metasomatized by slab-derived melt and mixed with crustal materials during the later evolution.Rhyolites are of mantle derived magma mixed with continental crust.Basalts have the characteristics of intraplate basalts and island arc magmatic rocks,while rhyolites show the characteristics of island arc magmatic rocks. Combined with the regional geological background,it is inferred that the volcanic rocks of the Yeba Formation in Maizhoukunggar were formed in the back-arc basin of the northward subduction of the Neo-Tethys ocean,and there are differences in the formation age and tectonic settings of the volcanic rocks of the Yeba Formation in the region,It may represent different products in different stages of subduction.
    2022  .  41(8):    1369-1381    [摘要](219)    [PDF](370)
  • Petrogenesis of the Shuicaoba monzonitic granite porphyry in Ninglang, Yunnan: constraints from zircon U-Pb geochronology and geochemistry
    WANG Hong, LI Youyu, ZHANG Jinrang, ZHOU Qing
    The Shuicaoba monzonitic granite porphyry is located north segment of the Xiangyun-ninglang Cu-Au metallogenic belt, and it is also an important part of the Jinshajiang-Red River enozoic alkali-rich porphyry belt.Based on petrography,zircon U-Pb geochronology and petrogeochemical analysis of the Shuicaoba Monzogranite porphyry,new constraints have be provided for the Cenozoic tectonic magmatic evolution in this area.LA-ICP-MS zircon U-Pb dating indicates that Shuicaoba monzonitic granite porphyry is of Early Oligocene (33.1±0.3 Ma).The pluton is rich in SiO2 and alkali,with the ratio of A/CNK>1,belonging to the peraluminaceous alkali rich monzonite porphyry.The rock has a total high amount of REE elements(ΣREE=114.68×10-6~384.79×10-6),right-leaning REE distribution pattern,and obvious fractionation of LREE((La/Yb)N=440.37~114.09),showing no significant Eu anomaly(0.84~1.14).The adakite is enriching in LILE(such as Rb,Sr and Ba) and HFSE (such as Th,U,K and La),depleting in HREE,high field strength elements (Nb,Ta,Ti,etc.),with a high amount of Sr and low amount of Y and Yb,which is typical C-type Adakite.Comprehensive analysis shows that the magmatic source area of the Shuicaoba monzogranite porphyry is mainly partial melting of the thickened lower crust,and a small amount of mantle-derived components may be involved.Combined with the regional tectonic evolution,it is considered that the Shuicaoba monzogranite porphyry was formed under the dynamic background of the tectonic stress transition from compression to extension during the late Indian-Eurasian plate collision strike slip period.
    2022  .  41(8):    1382-1393    [摘要](220)    [PDF](303)
  • Late Jurassic A-type granite in Sharhada, West Ujimqin, Inner Mongolia: geochemical characteristics, petrogenesis and geodynamic setting
    HU Peng, DUAN Ming, XIONG Jinlian, ZENG Wei, LIU Xing, YAN Guoqiang, WEI Jialin
    The Sharhada granite in West Ujimqin, Inner Mongolia intruded into ophiolite in Hegenshan suture. LA-ICP-MS zircon dating indicates that the Sharhada granite was emplaced in the Late Jurassic (154.6±1.2 Ma). The mineral assemblage of the Shardaha granite is mainly composed of quartz, alkali feldspar and plagioclase. The granite is characterized by high SiO2 (74.86%~75.97%), K2O(4.4%~4.95%), low MgO (0.044%~0.22%), CaO (0.38%~0.77%), TiO2 (0.046%~0.18%) and P2O5 (0.007%~0.042%), A/CNK=1.03~1.09 < 1.1. It is strongly depleted in Ba, Sr, Eu, P and Ti, with a typical right dipping "Seagull-type" REE distribution pattern,showing the geochemical characteristics of typical aluminous A-type granite. The Sharhada A-type granite has low (87Sr/86Sr)i (0.7014~0.70374), positive εNd(t) values (+ 3.96~+ 4.31) and high εHf(t) (+ 10.54~+ 14.72), which may due to the partial melting of the newly formed intermediate/basic crustal materials and the subsequent crystallization differentiation. Furthermore, together with other A-type granites scattered in the Mongolia-Northern North China block, the Sharhada A-type granite is recognized as the product of the post-orogenic extension of the Mongolian-Okhotsk tectonic domain in the Late Jurassic, which indicates the extensive middle-lower crust extension in the Middle-Late Jurassic.
    2022  .  41(8):    1394-1408    [摘要](236)    [PDF](307)
  • Age limit of diabase dyke intrusion in Tangwangzhai-Yangtianwo compound syncline in the northern section of Longmen Mountain, western Sichuan Province
    DING Xiao, LI Zhongquan, LI Jianing, LI Hongkui, CHEN Xiao, LIU Ran, YANG Yuanyu, YING Wenfeng
    Tangwangzhai-Yangtianwo compound syncline is a typical slip nappe structure in the Longmen Mountain foreland structural belt in Western Sichuan.Six diabase dikes are developed in its northeast part,and limiting its intrusion time is helpful to understand the tectonic evolution of the northern Longmen Mountain.In order to determine the invasion time of diabase dyke,this paper defines the geological age of the lower limit of diabase dyke invasion through field geological investigation and the relationship between the formation,evolution,superposition and cutting of regional structures.The results show that:①In the complex fault fold belt in the front of Longmen Mountain,the Late Triassic Xujiahe Formation and Jurassic continental clastic rocks are in parallel or angular unconformity contact,which are superimposed on the Devonian,Carboniferous,Permian and early Middle Triassic marine strata,The Tangwangzhai-Yangtianwo compound syncline was formed in the Indosinian-Yanshanian period after the Middle Triassic;②Tangwangzhai-Yangtianwo compound syncline is located on a large area of Silurian weak shale,and no fault scratch is found on the contact surface.The plastic rheology of the underlying Silurian is the main factor for the formation of the syncline prototype;③Because diabase dykes cut the Tangwangzhai-Yangtianwo compound syncline,their intrusion age should be after the deposition of the Leikoupo Formation in the Middle Triassic.225~158 Ma should be the distribution range of intrusion age of diabase dyke.
    2022  .  41(8):    1409-1416    [摘要](215)    [PDF](289)
  • Research status and prospects of marine-continental transitional shale reservoirs
    LI Qiqi, XU Shang
    The Carboniferous-Permian transitional organic-rich shales are widely distributed in China,and the development of shale gas in them is of great significance to alleviate the huge energy and environmental pressure.The key properties of representative transitional shales in different regions and layers are summarized from the aspects of sedimentary environments,geochemistry,mineralogy,and petrophysics,and compared with typical marine and continental shales.The results show that for the transitional shales,the swamp facies in the delta system and the lagoon and swamp facies in the barrier-lagoon system have superior conditions for shale gas accumulation.The transitional shales are frequently interbedded with coal and sandstone layers,and the vertical change of lithofacies is extremely complex,implying that they are highly heterogeneous.At the same time,the vertical variation of TOC content is large,and the average TOC content is generally higher than that of marine and continental shales,which means that it has great potential for shale gas exploration and development.The organic matter type of marine-continental transitional shales are mainly Type III,supplemented by Type II,humic maceral accounts for about 70%.The degree of thermal evolution is generally in the stage of maturity to high maturity,with a few reaching over-maturity,and generally between continental and marine shales.The high clay mineral content of transitional shales poses a great challenge to fracturing development.The reservoir space is dominated by intergranular pores and intragranular pores,and a large number of invisible organic matter pores prevalent in organic matter,but they are not theoretically the dominant pore type in transitional shales due to the type and maturity of the organic matter.High clay content may result in the lowest porosity and low permeability of marine-continental transitional shales.The methane adsorption capacity of transition shales are distributed in a wide range,and there are shales with strong methane adsorption capacity,which may be influenced by coal seams.At present,many important research results have been achieved in the study of marine-continental transitional shale gas reservoirs.However,the imperfection of resource evaluation methods,the immaturity of "sweet spot" recognition and prediction technology,the lack of in-depth study on favorable reservoir formation environment,and the uncertainty of the feasibility of the co-mining of various unconventional natural gas resources are the main problems in the exploration and development of transitional shale gas.
    2022  .  41(8):    1417-1429    [摘要](198)    [PDF](277)
  • Sedimentary environment and organic matter enrichment model of black shale from Cretaceous Bayingebi Formation in Balongwula, Yingen-Ejin Banner Basin
    SHI Jizhong, CUI Haifeng, XU Wei, SONG Bo, WANG Baowen
    The lacustrine shale of Early Cretaceous Bayingebi Formation is a suite of important source rocks resources in the Yingen-Ejin Banner basin.We studied the characteristics of the major elements,trace elements and rare earth elements,and the paleoenvironment and organic matter enrichment model of the black shale by the geochemical analysis of the Balongwula section.The results show that Sr/Ba value is 0.14~0.24,average value is 0.18,B/Ga value is 3.89~6.51,average value is 5.03,equivalent boron content is 230.88×10-6~375.99×10-6,average value is 294.95×10 -6,paleosalinity is 11.97‰~15.83‰,average value is 14.70‰; V/(V+Ni) value is 0.67~0.84,average value is 0.74,the Ceanom value is -0.113~0.018,average value is -0.055; the paleoclimate index(C) is 0.80~1.34,average value is 1.06,the chemical index alteration(CIA) is 75~81,average value is 79; the ancient water depth is 4.16~88.04 m,average value is 33.40 m; P/Ti value is 0.10~0.22,average value is 0.15,the excess barium(BaXS) is -46.5×10-6~144.5×10-6,average value is 38.85×10-6.Based on the characteristics of various parameters,the black shale in the study area is deposited in a warm and humid climate,with a sedimentary environment of deep lacustrine facies under an brackish water and anoxic condition.The paleoproductivity reflect a low initial paleoproductivity.The study on the correlation between organic carbon content and sedimentary environment shows that the organic matter enrichment in black shale of Bayingebi Formation is the result of the combined action of paleosalinity,oxidation-reduction conditions,paleoclimate and paleo-productivity.This will provide theoretical support for the sedimentary evolution of Mesozoic and the evaluation of oil and gas resources in Yingen-Ejin Banner Basin.
    2022  .  41(8):    1430-1444    [摘要](198)    [PDF](299)
  • Quantitative analysis of mineralization-alteration index and deep prospecting significance of Qilinchang Pb-Zn deposit in Huize, northeastern Yunnan
    ZHANG Xiaopei, HAN Runsheng, ZHAO Dong, ZHANG Yan, QIU Wenlong, HE Jiaojiao, CUI Junhao
    The giant Huize Pb-Zn deposit is the most representative deposit of Pb-Zn polymetallic ore concentration area in northeastern Yunnan.In order to effectively extract and distinguish the mineralization-alteration information such as lead-zinc mineralization,pyritization and dolomitization in different mineralization-alteration zones,using large scale alteration petrographical mapping method,taking the typical levels of 1249 m as an example,to analyze the levels' mineralization-alteration types,altered rock composition,structure and other characteristics base on quantitative analysis of hydrothermal alteration index and growth index of element transfer-in.The results show that the main alteration types are dolomitization,calcitization and pyritization.Mineralization mainly are sphalerite and galena.Taking the ore body as the center,from footwall rock of ore body to ore body to hanging wall rock of ore body,the mineralization-alteration zoning shows that grayish white coarse-grained crystalline dolomite which is far from the orebody(Ⅰ),coarse-grained dolomite with pinholes(Ⅱ),beige coarse-grained crystalline dolomite(Ⅲ),grayish white coarse-grained crystalline dolomite which is closed to the orebody(Ⅳ),orebody(Ⅴ)and grayish white coarse-grained crystalline dolomite which is closed to the orebody(Ⅳ).The element TFe,CaO,MgO,Pb,and Zn in the different mineralization alteration zones almost keep transfer-in.Among them,the element TFe,Pb and Zn are the most obvious.Moreover,the quantitative calculation results of the mineralized alteration rocks' mineralization alteration index and the growth index of the elements transfer-in are consistent with the mineralization alteration zone in space.The values of alteration index(AI),TFe's alteration index(AITFe),and(Pb+Zn)'s alteration index(AIPb+Zn)are the highest in the Ⅴ zone while the value of MgO's alteration index(AIMgO)is the lowest,clearly distinguished from other alteration zones; The values of Zn,Pb and TFe's growth index of element transfer-in(ZZn,ZPb and ZTFe)are generally increasing from Ⅰ zone to Ⅴ zone,and the values of ZZn,ZPb and ZTFe are significantly higher than those in surrounding rock.The study of mineralization alteration index reveals the relationship between hydrothermal alteration and mineralization,and also proves the rationality of spatial mineralization alteration zoning,which has guiding significance for deep exploration of similar deposits.
    2022  .  41(8):    1445-1461    [摘要](213)    [PDF](297)
  • Damage characteristics and cause of Ms 6.4 earthquake in Yangbi, Yunnan Province on May 21, 2021
    XIONG Wei, HUANG Xiaolong, WU Zhonghai, ZHANG Haijun, SHI Yaran, FAN Ne, HAN Shuai
    Yangbi area,located in the southeast margin of Qinghai-Tibet Plateau,is characterized by complex geological structure,which leads to the occurrence and behavior of earthquakes controlled by many factors.In order to clarify the intensity distribution characteristics,damage characteristics and influencing factors of Yangbi Ms 6.4 earthquake,the research work was carried out by means of interview,field investigation and statistical analysis.The results show that the intensity of the Yangbi Ms 6.4 earthquake in the extreme earthquake area can reach Ⅷ,and the major axis of the isoseismal ellipse deflects NW,which is consistent with the relocation of the earthquake sequence and the solution of focal mechanism,indicating that the seismogenic fault is a Caoping fault with NW-SE strike and SW dip and right-handed strike-slip property.Among them,the Ⅷ degree area deflects by about 30 at the southeast,which is affected by the tensile fracture effect at the tail end of the fault.The isoseismal line in the Ⅶ degree area is prominent in the opposite direction to the fracture tendency,and the overall range of intensity is much smaller than the previous survey results,which may be related to the difference of topography,physical properties on both sides of the fault,basin focusing effect and edge effect of seismic waves,as well as the influence of the intensity amplification effect caused by soft valley sediments,high groundwater level in the valley basin and high altitude of Cangshan Mountain.The earthquake damages developed in the above-mentioned intensity areas are mainly the destruction of houses and seismic geological disasters,in which the destruction of houses is more serious and the scale of seismic geological disasters is smaller.The types of geological disasters are mainly landslides and ground fissures.After investigation and analysis,it is found that they do not show the characteristics of concentrated development along faults or extreme earthquake areas,which are more affected by factors such as topography,surface media and groundwater.
    2022  .  41(8):    1462-1472    [摘要](209)    [PDF](300)
  • Seismic landslide hazards assessment along the Xianshuihe fault zone, Tibetan Plateau, China
    LI Caihong, LI Xue, GUO Changbao, ZHANG Xujiao, YANG Zhihua
    The Xianshuihe fault zone is a large active left-lateral strike-slip fault zone in the southeast margin of Qinghai-Tibet Plateau,Southwest China,the geomorphology and geological structure along the fault zone is complex,and historical earthquakes occur frequently,which induce a large number of seismic landslide disasters,causing a huge impact on major construction projects and people's lives and properties.For the long-term prevention of seismic landslides in the Xianshuihe fault zone,an area of about 20 km on both sides of the Xianshuihe fault zone was selected for remote sensing interpretation and field geological survey,a total of 399 historical seismic landslides were found in the region,with overall characteristics of high remote,one slide to the bottom and cracked but not slipped.On the basis of studying and analyzing the disaster background and development and distribution characteristics of regional geological disasters,the Newmark model was used to complete the seismic landslide hazards assessment with exceeding probability 10% of 50 years in Xianshuihe fault zone.The results showed that the extremely high-risk area,high-risk area,medium-risk area,and low-risk area of seismic landslides account for 6.28%,11.77%,33.33%,and 48.62% of the total area of the study area,respectively.The Kangding-Moxi section and the vicinity of Dadu River are areas with high seismic landslide hazards.63.66% of seismic landslides are distributed in extremely high and high seismic landslide hazards areas,the test results of the success rate (ROC) curve show that the accuracy of the landslide risk assessment is 74.3%,and the accuracy of the evaluation results is high.The Sichuan-Tibet Railway under planning and construction extends from Luding County and Kangding City,where there is a high risk of seismic landslide.Therefore,it is necessary to strengthen the evaluation and prevention of potential seismic landslide hazards near the railway tunnel entrance in the project planning and construction.The seismic landslide hazards zoning results of the Xianshuihe fault zone will provide reference materials and scientific guidance for the prevention and control of seismic and geological disasters in this region and the construction of the Sichuan-Tibet railway.
    2022  .  41(8):    1473-1486    [摘要](207)    [PDF](309)
  • Research on the evaluation of land resources carrying capacity in Jinzhou area, Liaoning Province
    SUN Xiubo, CUI Jian, DAI Yajian, GUO Changlai
    Taking the best comprehensive carrying state of land resources as the target layer,and taking the bottom line of land resources,green life,land resource security,and green production of land resources as the criterion layers,establish an evaluation index system for the carrying capacity of land resources in Jinzhou.The objective weighting,advantages and shortcoming evaluation modules establish a quantitative analysis model for TOPSIS land resource carrying capacity evaluation and advantages shortcomings.Based on this model,the evaluation research of land resource carrying capacity in Jinzhou area was carriedout.The evaluation results show that from 2015 to 2018,the land resource carrying capacity of Jinzhou area increased first and then decreased,reached the highest in 2016 and the lowest in 2018.The scale of urban and rural construction land in 2015,the scale of ecological restoration of new land and space in 2016,and the amount of cultivated land in 2018 are the main indicator that affected the land carrying capacity of that year. The results provide support for studying the evolution trend of land resource carrying capacity and quantitatively analyzing the indicators that affect land resource carrying capacity.
    2022  .  41(8):    1487-1493    [摘要](204)    [PDF](292)
  • Instability mechanism and stability trend of loess slope during seasonal Freeze-thaw process
    ZENG Lei, JIA Jun
    Seasonal freeze-thaw landslides are one of the main types of loess disasters.The groundwater response is extremely sensitive during seasonal freezing and thawing.The distribution and changes of groundwater level have a greater impact on the stress state,mechanical properties and slope stability of the rock and soil in the loess slope.Slope caused by stagnant water during freezing and draining during thawing.The change of groundwater level within the scope is one of the main inducing factors for the stability change and instability of the loess slope.Based on the whole process of slope groundwater change during seasonal freezing and thawing,this paper adopts the slice method based on limit equilibrium theory and the finite element numerical method based on elastoplastic theory to analyze and calculate the slope stability and slope stress and strain field response.Under seasonal freezing and thawing conditions,the failure mechanism and stability change trend of the slope of loess slopes.Provide scientific basis for early warning and prevention of seasonal freeze-thaw landslides.
    2022  .  41(8):    1494-1503    [摘要](202)    [PDF](275)
  • The geochemistry characteristics, zircon U-Pb ages and tectonic significance of the Early Carboniferous—Middle Triassic oceanic crust subduction of the Wudaomen pillow basalts in Keshiketeng Banner, Inner Mongolia
    DUN Ming, HU Peng, YAN Guoqiang, ZHANG Feng, ZHANG Yongqing, CHEN Wentao, XIE Yu, LI Zhidan
    2022  .  41(8):    1504-1507    [摘要](210)    [PDF](298)

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