【作者】 张春艳；

【导师】 张兴洲；

【作者基本信息】 吉林大学 ， 构造地质学， 2009， 博士

【摘要】 本文依据岩石学、地球化学、同位素年代学、古生物学及地球物理学新资料,对出露于吉林省烟筒山、延边地区青龙村群岩石的分布特征、物质组成、原岩类型、变质作用及形成的构造环境和时代进行了系统的研究。研究发现,吉林中部鹿圈屯组中的红帘石硅质岩为火山成因硅质岩。其主要岩石类型为石英片岩(硅质岩)、大理岩和绿片岩等。CL照片显示,硅质岩中锆石环带结构发育。锆石年龄测试表明,环带中心较老(290±3)Ma,而边部时代较新(239±11)Ma。根据锆石形态和Th/U比值(0.30~2.44)特点,说明火山作用的时代为古生代末,而变质变形时代为中生代(三叠纪)。因此,我们认为这两次事件分别记录了吉省林中部古亚洲洋闭合到陆陆碰撞过程所发生的重要事件。延边地区的青龙村群是一套经历了多阶段复杂变质变形作用的岩石组合。其中包括了多种不同类型的变质岩石,岩石类型主要包括:片岩类、斜长角闪岩类、粗细粒片麻岩类和大理岩夹层。锆石离子探针U-Pb测年结果显示,斜长角闪岩中锆石年龄为(274±6)Ma,侵入其中的梨树沟花岗岩体中的锆石年龄为(187±3)Ma,结合本文测定的相邻开山屯花岗岩锆石年龄为(194.2±4.1)Ma,以及最近的吴福元等对吉林省中部磐石地区呼兰群变质作用时代Rb-Sr矿物等时线年龄为250Ma左右,本文认为,延边地区的青龙村群及磐石地区的呼兰群变质作用时代是一致的,为二叠纪末期,代表华北板块北缘的碰撞造山事件,而周边大面积花岗岩的侵位时间为燕山期,说明华北板块北缘在碰撞造山之后有大规模的燕山期花岗质岩浆侵入事件。上述研究成果为深入认识吉林东部的构造演化提供了新的重要佐证。更多还原

【Abstract】 East Jilin Province, to the west of Sea of Japan, is located in the North China plateEast the accretion belt. It is a composite tectonic belt resulting from the interaction of thenortheast micro plate group and the North China plate. The geologic structure is extremelycomplex and also quite special owing to the superimposition of the Pacific Ocean plateaffection. In the Pro-mesozoic, the study area was mainly under a dynamic setting ofinteractions among the ancient Asian ocean plate, the Siberia plate and the North Chinaplate. It evolved from ancient Asian ocean subduction to two mainland plate accretion inopposite direction proliferation and then finally convergence. Since Mesozoic, this area hasbeen strongly influenced by the Pacific Ocean plate, so it has been an important constituentof the circum-Pacific tectonic belt. Its geological structure and evolution has been studiedby lots of people. From global structure, this area lying in east the central Asia orogeniczone the section, is an important constituent of the central Asia orogenic zone. However, itis not well known about the studied lithofacies and its relations to adjacent lithofacies.Therefore, we take the Qinglongcun group, the Hulan group and Piedmontite siliceous rockfrom Yantongshan region area as representative, their attribute and age can provide theimportant academic foundation to north the North China plate structure evolution. At thesame time, convergence and collision between the North China plate and Siberia plate playa important role to orogenic belt geology researc, thus also provides the importantinformation to the Northeast Asia geology research.There are lots of argument about the time and place when and where the ancient Asianocean closed. According to the traditional viewpoint, the ancient Asian ocean finally closedin the east part of the north the North China plate suture belt, specially is located to thewest of the Dunmi fault; to the north of Longgang massif, to the south of Xingkai massif.Paleontology and other aspect study shows, the finally sutures place should be locatedfrom the Xilamulun river-Changchun -Yanji in the north marge the North China plate, the time is possibly the permian. However, some geologists proposed this area had completedthe ocean and land convergence in the early Paleozoic through the Paleozoic rockformation. Because of the above contradiction, at present the majority of scholars use thepattern of“touch does not collision, spells does not gather”. In addition, the formerscholars also debated about the characteristics of rock in the suture belts of this area. Andmost geologists consider it’s a set of metamorphic complex.Based on the data and research from the former scholars, the distributioncharacteristics, material composition, the original rock type, metamorphism andconstruction environment of the piedmontite siliceous rock in Panshi County and theYanbian area Qinglongcun group include Space output are investigated in detailthrough the geology, petrology, geochemistry, paleontology and new geophysicaldata. At last, the tectonic implications are discussed in this paper.Piedmontite siliceous rock in the middle of Jilin Province exists in the Paleozoicquartz-schist (siliceous rock), marble and green schist and so on. According to the formerresearch, piedmontite siliceous rock in middle Jilin Province is muddy silicon rock, formedin the environment which related closely to continental margin source. It is indicated thatpiedmontite siliceous rock in study area is volcano origin silicon rock through petrologyand rock geochemistry research. In addition, according to the CL pictures, zircon agedistribution pellet scope is very complex, but the most situations are, the zonation center isold, 290±3Ma, this explanated that the volcanism time (country rock time) old, about theend of Paleozoic; But deformation and metamorphic time is 239±11Ma, mesozoic (Triassicperiod). So the metamorphic time has been defied Between 250-228Ma. Therefore, it isindicated that middle Jilin Province should be the place where paleo-Asian Ocean finallyclosed, and the closed time is the early Triassic period, deformation and metamorphism ofthe siliceous rock we studied is the above convergence geological record.Qinglongchun Group in Yanbian area is a set of lithological combination through thecomplexing metamorphic and deformational functions of the multistage sections. It iscontained various types of metamophic rocks including the schistose series, theamphibolite series, the gneiss series of rough grained, and marble division. Petrology andthe rock geochemistry research indicated that the original rock of Qinglongcun groupbelongs to the combination of calcium alkalescence andesite－rhyolite. Shrimp single zircon U-Pb isotopic age dating result showed that amphibolite zircon age dating result inQinglongcun group is 274±6 Ma, Lishugou granite body zircon age is 187±3 Ma, also theKaishantun granite zircon age is (194.2±4.1) Ma. Combined with the Rb-Sr isochronal ageof 250Ma for metamorphism in Panshi area, in the middle of Jilin from Wu Fuyuan recentresearch, we may draw the conclusion that Yanbian Qinglongcun group and the Hulangroup metamorphic time is late permian, which represents the collision orogenic event inthe north marge of the North China plate, and the intrusion time of large area granite isduring Yanshanian, which indicated the large-scale Yanshanian granite intruded in studyarea after the collision orogenic event in the north margin of the North China plate.Therefore, the research above provides more new and important evidences for furtherunderstanding the structure evolution in the east of Jilin province.更多还原