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2021yearNo.40volumeNo.1phase

  • 张进,王涛
    2021  .  40(1):    1-2    [摘要](53)    [PDF](29)
  • A geophysical technology for thematic geological mapping: Short period dense array
    LU Zhanwu, LI Wenhui, ZHANG Xinyan, LI Qiusheng, CAI Yuguo, REN Yanzong, CHENG Yongzhi, WANG Guangwen
    Thematic geological mapping driven by the demands and problems emphasizes that for different geological environments such as a major geological body,sedimentary basin,important metallogenic belt and fault system,modern technical means can be adopted to carry out thematic geological investigation and mapping,so as to solve some major problems of above-mentioned geological environments.Geophysics,as one indispensable means in thematic mapping,its short-period dense array technology developed in recent 10 years has attracted much attention due to flexible layout,wide application,high precision and low cost.This paper mainly introduces the current situation of short period dense array,and its application to near surface structure investigation under different geological and geomorphic conditions such as cities,mines,earthquake and sedimentary basins,etc.The application prospect and technical scheme suggestions of its technology in thematic geological mapping is put forward to improve and perfect the method system of thematic geological mapping technology by means of constructing structure imaging method through the investigation of short period dense array.
    2021  .  40(1):    1-12    [摘要](47)    [PDF](37)
  • Application of hyperspectral remote sensing technology to regional geological survey and mapping in bedrock area
    LI Na, DONG Xinfeng, GAN Fuping, YAN Baikun, ZHU Wanjing
    Compared with the traditional multi-spectral remote sensing data,hyperspectral remote sensing has the advantage of ultra-high spectral dimension data,which makes its ability of fine recognition and discrimination of ground objects improved qualitatively.Using HyMap hyperspectral data and GF-5 hyperspectral data as data sources,the litho-structural interpretation was carried out in the bedrock area of western China.Through image enhancement processing,remote sensing geological interpretation of stratigraphic units,intrusives/veins and structures in the study area was carried out.Compared with the existing geological survey results,it is found that the hyperspectral remote sensing data is more clear and intuitive than the multispectral and high resolution data in the distribution of litho-structural information.Meanwhile,the hyperspectral remote sensing data have prominent ability to distinguish different lithology,different lithofacies and small structures,showing obvious technical advantages.The results show that hyperspectral remote sensing can provide more objective and real geological body and structure distribution for regional geological mapping in the bedrock area,and improve the efficiency and quality of geological mapping.
    2021  .  40(1):    13-21    [摘要](49)    [PDF](42)
  • Establishment of the Middle—Upper Triassic Garezhadi Formation in the Coqen Block,Tibet
    SHI Qiuyuan, JI Zhansheng, WU Guichun, SUN Qian, HE Jifu, GUO Anchen, HOU Zhaoshuo, LI Dongze
    A new lithostratigraphic unit in the Middle Triassic-Upper Triassic Carnian,the Garezhadi Formation,was established in the Coqen Block,Tibet.In the profile of the newly established lithostratigraphic unit,the Garizadi Formation is about 485 m thick.The lower lithology is dominated by clastic rocks,while the upper lithology is clastic rocks intercalated with limestone.It is conformable with both the overlying Upper Triassic Mailonggang Formation and the underlying Upper Permian-Lower Triassic Mujiucuo Formation.No fossils indicating the stratigraphic age have been found in it,but Early Triassic conodonts have been found in the underlying Mujiucuo Formation by previous work,and in our project,eight coral species belonging to seven genus were identified in the overlying Mailonggang Formation,including Distichophyllia norica (Frech),Retiophyllia? sp.,Gablonzeria? sp.,Elysastraea juliana Turnšek,Volzeia sublaevis (Münster),Distichophyllia sp.,Guembelastraea? sp.,Beneckastraea baiyuensis.According to its conformable contact with the underlying and overlying strata,the age of Garezhadi Formation is temporarily limited to the Middle-Triassic Late Triassic Carnian period.Moreover,the stratum observed in the measured profile was reclassified based on the age of corals,lithology and its contact relationships.The establishment of the Garezhadi Formation filled the naming blank of the lithostratigraphic units of the restricted platform facies of Triassic sequence in Coqen block.Its establishment resulted in the Triassic stratigraphic sequence of the restricted platform facies being divided into the Upper Permian-Lower Triassic Mujiucuo Formation,the Middle Triassic—Upper Triassic Carnian Garezhadi Formation,the Upper Triassic Norian Mailonggang Formation,the Upper Triassic Rhaetian-? Lower Jurassic Quehala Formation in asending order.The establishment of this sequence has a guiding role in further identifying the Triassic system of restricted carbonate platform facies and revising the stratigraphic understanding of related areas in Coqen block.
    2021  .  40(1):    22-30    [摘要](37)    [PDF](40)
  • Identification of the relics of paleo-seamount in orogens: A case study from the geological mapping in Qingshashan and Donggou areas within the Lajishan suture zone
    FU Changlei, YAN Zhen, WANG Bingzhang, NIU Manlan
    Identification of the relics of seamount/oceanic island in orogens can provide critical geological evidence for the presence of the suture zone and paleo-ocean basin.The Qilian Orogen is widely considered as the product of subduction and closure of the Proto-Tethyan Ocean.However,whether there exists a paleo-ocean basin in the South Qilian is still hotly debated.Based on large-scale geological mapping and comprehensive study on the Early Paleozoic rocks in the key area of Lajishan,a successive volcanic-sedimentary sequence composed of OIB-type pillow basalt,pyroclastic rock,mudstone,tuff,and limestone was recognized in the Qingshashan and Donggou areas.The rocks are outcropped as the tectonic slice and tectonic window respectively.The volcanic-sedimentary sequence is the major components of the accretionary complex within Lajishan,and represents the relics of Middle Cambrian to Early Ordovician seamounts within the Proto-Tethyan Ocean.The identification of these relics of seamount not only indicates that there exist Early Paleozoic ocean basin and suture zone in the Lajishan area but also provides a new idea for the study of tectonic evolution of the paleo-ocean basin in orogens.
    2021  .  40(1):    31-40    [摘要](50)    [PDF](65)
  • Zircon U-Pb geochronology of the Baishahe Formation in the western part of East Kunlun Orogenic Belt: Constraints on Precambrian basement evolution
    LI Meng, ZHA Xianfeng, HU Chaobin, GAO Xiaofeng, LI Ting, YAO Zhiliang
    The geochronology of the detrital zircons of the gneiss in the Aquedun region,western part of the East Kunlun Mountains was studied by LA-ICP-MS method.The ages of the detrital zircons of the gneiss vary between 2400 Ma and 410 Ma with a peak ranging from 1650 Ma to 1400 Ma.Minor metamorphic zircons was dated as 1.0~0.9 Ga (Neoproterozoic) and 410 Ma (Early Paleozoic).The dating results imply that the protolith of the gneiss was deposited in Late Mesoproterozoic,and had undergone Neoproterozoic and Early Paleozoic metamorphism.Based on eclogite in gneisses formed in Early Paleozoic (450~410 Ma).Combined with a lot of Early Paleozoic metamorphic information from zircons in gneiss,it is speculated that the gneiss in this region also underwent Early Paleozoic eclogite-facies metamorphism,and gneiss and eclogite is in situ relationship.Combined with regional studies,it is suggested that there may exists a high pressure metamorphic belt of nearly 1000 km long in Early Paleozoic in East Kunlun,which may be the product of subduction and reentry.
    2021  .  40(1):    41-57    [摘要](41)    [PDF](46)
  • Petrogenesis and tectonic setting of the Late Permian A-type granitic dyke swarm in Ulungur,East Junggar
    LU Peng, TONG Ying, MENG Qiuyi, ZHANG Huafeng
    A large number of Late Paleozoic granites occur in the East Junggar on the southwest margin of the Central Asian Orogenic belt, providing a good chance to reveal the crustal evolution of the Central Asian Orogenic Belt. In this study, a series of Late Paleozoic granitic dykes striking vertically to the suture zone were recognized in Akejila, northwest of Ulungur of East Junggar. Their timing of emplacement and petrogenesis are critical to understand the tectono-crustal evolution of the study area. SHRIMP zircon U-Pb dating yielded a Late Permian age (266±2 Ma). Geochemical analyses indicate that they are characterized by relatively high concentration of silica (SiO2=75.66%~76.69%) and alkali (Na2O+K2O=8.67%~9.16%),but low calcium (CaO =0.06%~0.14%) and magnesia (MgO =0.04%~0.06%)content. The obvious negative Eu anomaly (δEu=0.16~0.18), relative depletion of Ba,Sr,P and Ti,and significant enrichment of Nb, Zr, Th, Ta and Hf, as well as high Ga/Al value (>2.6) characterize the weakly peraluminous A1 type granites. The positive εNd(t) value (+4.7) and a young model age (655 Ma) suggest that these dykes are mainly derived from the juvenile mantle. Therefore, the comprehensive analysis indicates that the dykes were formed by the partial melting of the juvenile lower crust caused by the upwelling of the mantle in a post-collision setting.
    2021  .  40(1):    58-70    [摘要](37)    [PDF](33)
  • Research status and progress of Paleozoic ophiolites in Beishan orogenic belt
    WANG Guoqiang, LI Xiangmin, XU Xueyi, YU Jiyuan, WU Peng, JI Bo
    As one of the most important parts of orogenic belt,the formation and emplacement of the ophiolitic mélange belt is closely related to regional orogenic events.Four ophiolitic mélanges belts are involved in the Beishan orogenic belt,of which the Hongliuhe-Niujuanzi-Xichangjing ophiolitic mélange belt is the oldest one,indicating that the Bishan Ocean was opened as early as Early Cambrian,and might be closed in Permian at the latest.The study of tectonic affinity also shows that the evidence for the division of the discovered ophiolitic mélange zones as the first-scale tectonic unit is still insufficient.Because the identification,formation,emplacement age of ophiolites and evolution of various ocean basins,as well as their tectonic properties are restricted by objective expression about geological survey of Beishan ophiolite belts,it is suggested that one of the key means to further study and solve hot issue in the area in the future is to pay attention to the large scale fine basic geological survey of each ophiolite belt.
    2021  .  40(1):    71-81    [摘要](41)    [PDF](60)
  • Discovery of Late Carboniferous adakite in Manita,Inner Mongolia,and its constrains on intra-oceanic subduction in eastern Paleo-Asian Ocean
    WANG Shuai, LI Yingjie, WANG Jinfang, DONG Peipei, LI Hongyang, GUO Leiliang, WANG Xuanchen
    The Late Carboniferous Manita adakite distributed along the Hegenshan suture zone in the eastern part of the Xingmeng Orogenic Belt was discovered to be outcropped in the northern section of Diyanmiao SSZ ophiolite in Xiwuqi,Inner Mongolia.It consists mainly of granodiorite and plagiogranite,which belongs to low-K tholeiitic and Calc alkaline series,chemically characterized by 61.91%~75.16% of SiO2,13.54%~17.42% of A12O3,and 0.33%~2.49% of MgO,with intensively rich in Na2O (4.58%~5.48%),poor in K2O (0.40%~2.08%) and high ratio of Na2O/K2O (2.35~12.96).The Manita adakite also manifests high Sr (309.55×10-6~433.99×10-6) and poor Y (3.74×10-6~14.66×10-6),with relatively enriched large ion lithophile elements (LILE) K,Rb,Sr,and depleted high field strength elements (HFSE) Nb,Ta,Zr,Ti and P,etc.In addition,it features low ∑REE (35.79×10-6~70.10×10-6) and clear REE fractionation((La/Yb)N=1.59~10.11),without obvious Eu anomaly (δEu=0.91~1.51),and contains Yb (0.60×10-6~1.86×10-6).All of the geochemical characteristics indicate that the Manita pluton belongs to typical adakite.The U-Pb age of LA-ICP-MS zircon is 315.76±0.94 Ma,indicating that the formation age of Manita adakite is Late Carboniferous.The Manita adakite,Diyanmiao SSZ ophiolite,fore arc basalt and Baiyinhushu trondhjemite constitute the intra-oceanic subduction rock assemblage,which indicates that the eastern part of the Paleo-Asian Ocean was not closed in the Late Carboniferous and was in the process of subduction and extinction.
    2021  .  40(1):    82-94    [摘要](37)    [PDF](36)
  • Ore-controlling structure and deep prospecting of the Bayan Obo large-sized REE-Nb-Fe ore deposit,Inner Mongolia
    KE Changhui, SUN Sheng, ZHAO Yonggang, LI Yike, XU Zhongyuan, HAO Meizhen, LI Ruiping, ZHANG Li
    Analysis on folds and faults of the Bayan Obo REE-Nb-Fe orefield indicates that its structural activities witnessed multi-stage evolution.There exist at least four periods of structural activities from Mesoproterozoic to Hercynian which control metallogenesis and diagenesis,including the nearly EW-trending litho-controlling fault (F1),the nearly EW-trending strike-slip fault (F2),the nearly EW-trending ductile shear zone and folds and the left lateral strike slip normal fault (F3).Based on a comprehensive analysis it is concluded that:a.The nearly EW-trending fault (F1) distributed along the boundary between dolomite carbonatite and hangingwall or footwall controls the intrusive occurrence and the formation of ore bodies;b.After the emplacement of dolomite carbonatite,the ore body was destroyed by the nearly EW-trending strike-slip faults (F2) for the first time.As a result,the deep ore bodies in the south of the Main and East mines moved from west to east,and the deep orebody encountered by borehole WK14-01 should be caused by the translation of deep orebody in the south of the Main mine;c.The post-ore NS-trending compression destroyed ore body for the second time and brought about tight folding of the Bayan Obo Group strata and lensing of ore body;d.The left lateral strike slip normal fault (F3) distributed between the main mine and east mine destroyed ore bodies for the third time and led to the dislocation of the Main mine and East mine.The above research results and understanding will be of great guiding significance to the prospecting in the deep and periphery of the mine.
    2021  .  40(1):    95-109    [摘要](44)    [PDF](59)
  • Intracontinental deformation,paleo-stress field and tectonic setting in northeastern Alxa Block since Late Mesozoic
    ZHANG Beihang, ZHANG Jin, QU Junfeng, ZHAO Heng, NIU Pengfei, HUI Jie
    Intracontinental deformation and its tectonic setting is one of the hot topics of geological research. As the Langshan area in northeastern Alxa Block experienced multistage intracontinental deformations since Late Mesozoic,it is an ideal representative region to study intracontinental deformation. Based on large-scale structural mapping,detailed geological survey to clarify field cutting relationship,combined with published zircon geochronology and low-temperature thermochronology results,six stages of intracontinental deformation since the Late Jurassic in Langshan area have been determined.The vector data inversion of fault planes indicates that the deformations in different periods were formed in different paleo-stress fields. Both the previous structures and continuous accretion to the Eurasian continental margin from different directions control the tectonic evolution of Langshan area since Late Jurassic.From Late Jurassic to Late Cretaceous,the tectonic deformations of the Langshan area were mainly affected by the Paleo-Pacific tectonic domain,whereas,in Cenozoic,it began to be affected by the tectonic evolution of the Qinghai-Tibet Plateau.
    2021  .  40(1):    110-124    [摘要](33)    [PDF](39)
  • Response of magmatic activity to the closure of Changning-Menglian Palaeothys in western Yunnan: Evidence from geo-geochemical study on granite in southern section of Lincang pluton
    YUAN Xinchen, YANG Qijun, LYU Yong, PAN Ming, GAO Aiyang, XU Fang
    Lincang intrusive,as the largest exposed compound batholith of southern Lancangjiang in western Yunnan,and an important component of tethys tectonic domain,is mainly biotite monzogranite in lithology.The zircon sample collected frome granite was dated to 225.1±6.1 Ma,suggesting that these intrusives were emplaced during the Late Triassic.The K2O/Na2O value of Lincang granite is greater than 1,and the aluminum saturation index A/CNK ranges from1.05 to 1.95,indicating that Lancang intursives are derived from S-type granite with high potassium calcium basic peraluminum-super peraluminum.Intursives are remarkably characterized by enriched LREE and depleted HREE with (La/Yb)N=6.06~21.01 and δEu of 0.20~0.38.The petro-geochemistry of intusives indicates that the Lincang granite should be the product of the Changning-Menglian Palaeothys closure process,and the original rock of Lincang granite is lithologically clay-poor metamorphic sandstone and metamorphic mudstone in the middle and lower crust.The syncollision represented in its Pearce structure discrimination diagram is a response to the Palaeothys ocean closure and the Baoshan-Simao block collision.
    2021  .  40(1):    125-137    [摘要](35)    [PDF](30)
  • The tectonic setting of the Early-Middle Triassic volcanic-sedimentary succession in Funing-Napo area,the south margin of Nanpanjiang Basin,South China
    XIANG Zhongjin, YAN Quanren, XIA Lei, XIA Wenjing
    The Late Paleozoic to Early Mesozoic tectonic evolution process along the Sino-Vietnam border,particularly the subduction polarity of the Late Paleozoic ocean basin,is still controversial.Massive Early—Middle Triassic magmatic rocks and thick Triassic siliciclastic system occurred in the south margin of Nanpanjiang Basin provide important magmatic and sedimentary evidences for settling dispute.The Funing-Napo Triassic volcanic rocks,as the largest magmatic outcrop,are the ideal object for studying the tectonic evolution along the Sino-Vietnam border.The systematic profile survey and geological mapping indicates that the volcanic-sedimentary succession that consists of lower basaltic andesites overlain by carbonate conglomerates,pebbly sandstones and calcareous sandstones,which is similar to the volcanic-sedimentary sequence in island arc setting.Zircon SHRIMP U-Pb dating results of basaltic andesites are 247±1 Ma and 246±3 Ma,which are consist with field occurrence that basaltic andesite is overlain by Middle Triassic clastic rocsk.Combined with previous results,it is determined that the volcanic rocks were formed at 247~242 Ma.The geochemical analysis shows that basaltic andesites are enriched in LILEs (Rb,Th and U) and LREE,with a remarkable negative Nb-Ta and Ti anomalies.Both the geochemical characteristics of basaltic andesites and the volcanic-sedimentary sequence suggest that the Early—Middle Triassic volcanic-sedimentary succession was formed in a subduction-related arc setting.The spatial and temporal distribution characteristics of Early-Middle Triassic volcanic arc and ophiolitic mélange,implies that a north-dipping subduction occurred along Sino-Vietnam border.
    2021  .  40(1):    138-151    [摘要](30)    [PDF](35)
  • Early early-Cretaceous post-collisional tectonic setting of the southern segment of the Great Xing'an Range: Evidence from the Lanjiayingzi gabbro-diorite in Linxi area
    CHE Yawen, LIU Jianfeng, ZHAO Shuo, GE Maohui, LYU Qianlu
    Based on the systematic petrology,zircon chronology and geochemistry analysis of the Lanjiayingzi gabiodiorite pluton in the north of Linxi County in southern Great Khingan Range,genesis of the pluton and the Early Cretaceous tectonic setting are discussed.Zircon U-Pb dating reveals that the pluton was formed in Early Cretaceous (145.6±0.6 Ma).Geochemistry of the pluton is characterized by 53.38%~54.45% of SiO2 contents,1.34%~1.43% of K2O contents and 3.85%~4.05 % of Na2O contents,with 0.8~0.9 of A/CNK,which indicates that the pluton belongs to a calc-alkaline metaluminous magmatic rock.Its MgO and TFe2O3 contents vary from 5.44%~5.73% and 7.53%~8.33% respectively,with 36.96 to 38.24 of Mg# values.Combined with the girdle of plagioclase and the poikilitic texture of olivine in clinopyroxene,it is suggested that the pluton was the product of the fractional crystallization of mantle-derived primary magma.In addition,the pluton is relatively rich in LILEs such as Rb and Ba,and depletion in HFSEs such as Nb and Ta,with +5.4 to +9.0 of zircon εHf(t) values, which indicates that the pluton was derived from a depleted lithospheric mantle that experienced metasomatism from the subduction fluid.The Lanjiayingzi gabbrodiorite and coeval A-type granites in Linxi area constitute the bimodal magmatic assemblage,which suggests that they were formed in an extensional setting.Combined with regional geology,it is suggested that the formation of the Early Cretaceous magmatic rocks in southern Great Khingan Range has relation with the post-collision extensional setting resulting from closure of the Mongol-Okhotsk Ocean.
    2021  .  40(1):    152-163    [摘要](37)    [PDF](38)
  • Depositional timing and provenance of the Lugezhuang Formation in the Jingshan Group in the Jiaobei terrane: New evidence from detrital zircon U-Pb ages and rare earth elements of arkose-quartzite in Mayudian,Shandong Province
    ZHANG Lianxiang, LIU Pinghua, TIAN Zhonghua, ZHOU Wanpeng, WANG Yilong, WANG Hongyu, ZHANG Wen, ZHANG Chuanheng
    As the Lugezhuang Formation of Jingshan Group is one of the most important parts of the Paleoproterozoic meta-sedimentary rocks in the Jiaobei terrane,accurate determination of its depositional timing and provenance is of great geological significance for further exploring the genetic relationship between the Jingshan Group and the Fenzishan Group.A comprehensive study on mineral inclusions,cathodoluminescence(CL)images,LA-ICP-MS U-Pb dates,and in-situ rare earth element(REE)compositions of detrital zircons indicates that the age of detrital zircons of the arkose-quartzite of the Lugezhuang Formation in the Muyudian area ranges from 2502 Ma to 1970 Ma,of which the youngest group age of detrital zircons is circa 2079 Ma.Combined with its metamorphic age of circa 1934 Ma of the Lugezhuang Formation,it is preliminary determined that the depositional timing of the Lugezhuang Formation ranges from 2079 Ma to 1934 Ma.On the basis of above and published data,detrital zircons from the Lugezhuang Formation of Jingshan Group,Lieryu Formation of South Liaohe Group and Mayinghe Formation of the Ji’an Group all have a single peak of 2200~2100 Ma.The Xiaosong Formation and Zhujiakuang Formation of Fenzishan Group,Liangzishan Formatin of North Liaohe Group and Dataishan Formation of Laoling Group are all characterized by peak ages greater than 2500 Ma.Combining with geology of the Jiao-Liao-Ji belt,it is speculated that the Xiaosong Formation and Zhujiakuang Formation of the Fenzishan Group might be deposited close to the passive continental margin,while the Lugezhuang Formation of the Jingshan Group might be deposited closer to the magmatic island arc.Therefore,the rocks of Fenzishan Group and Jingshan Group might be simultaneously deposited in different sedimentary facies.
    2021  .  40(1):    164-188    [摘要](29)    [PDF](29)
  • New discovery of Jurassic dinosaur fossils in Chaya area,Qamdu district,Tibet
    AN Xianyin, WANG Qiyu, LI Yong, WANG Baodi, WANG Dongbing
    The dinosaur fossils were discovered in Jurassic red beds in Chaya area,Qamdu district,Tibet, mainly including ribs,vertebral bodies and so on,and their well preserved cervical vertebrae and scapula and pubis were morphologically described.Despite some difficulties in the attribution of species since few materials have been discovered so far,the discovery enriches the Jurassic dinosaur-bearing localities.Many dinosaur bones have been discovered in this area,indicating that they are relatively abundant.Further exploration and study of dinosaur fossils in the region will help us better understand the early evolution and differentiation of sauropods and theropods in Asia.
    2021  .  40(1):    189-193    [摘要](140)    [PDF](294)

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