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1.
Dong Yu Wang SiMiao Yu Qian Chen JingSheng Yang Hao Ge WenChun Bi JunHui Jing JiaHao 《岩石学报》2022,(8):2249-+
Northeastern China is suited in the eastern part of the Central Asian Orogenic Belt, and it is mainly composed of Erguna Massif, Xing'an Massif, Songnen-Zhangguangcai Range Massif, Jiamusi Massif, and Nadanhada Terrane. The Late Paleozoic magmatism was relatively intense accompanied with multiple stages of amalgamation in several microcontinents, therefore these magmatic products are an important media in recording the Late Paleozoic tectonic evolution history of the northeastern China. According to the petrological, geochronological, and geochemical characteristics of Late Paleozoic igneous rocks in the northeastern China, we found that the Late Paleozoic magmatism was based on Carboniferous -Permian igneous rocks. The Early Carboniferous magmatic products are gabbro, diorite and granite, the Late Carboniferous magmatic products are mainly composed of granitoids with minor gabbro, and the Permian magmatic products are mainly granitoids. Meanwhile, these Late Paleozoic igneous rocks mostly exhibit typical arc characteristics. In addition, the Late Paleozoic igneous rocks in eastern Jilin and Heilongjiang provinces are mainly Permian granitoids with minor gabbro, and these Permian igneous rocks show typical arc characteristics. Combined with petrological, geochronological, geochemical and isotopic characteristics, we suggest that the Late Paleozoic igneous rocks in the Great Xing'an Range and eastern Jilin and Heilongjiang provinces underwent different magmatic evolution history, and the microcontinents in NE China had different crustal growth history. 相似文献
2.
Highly fractionated I-type granites in NE China (II): isotopic geochemistry and implications for crustal growth in the Phanerozoic 总被引：11，自引：0，他引：11
Fu-yuan Wu Bor-ming Jahn Simon A. Wilde Ching-Hua Lo Tzen-Fu Yui Qiang Lin Wen-chun Ge De-you Sun 《Lithos》2003,67(3-4):191-204
NE China is the easternmost part of the Central Asian Orogenic Belt (CAOB). The area is distinguished by widespread occurrence of Phanerozoic granitic rocks. In the companion paper (Part I), we established the Jurassic ages (184–137 Ma) for three granitic plutons: Xinhuatun, Lamashan and Yiershi. We also used geochemical data to argue that these rocks are highly fractionated I-type granites. In this paper, we present Sr–Nd–O isotope data of the three plutons and 32 additional samples to delineate the nature of their source, to determine the proportion of mantle to crustal components in the generation of the voluminous granitoids and to discuss crustal growth in the Phanerozoic.
Despite their difference in emplacement age, Sr–Nd isotopic analyses reveal that these Jurassic granites have common isotopic characteristics. They all have low initial 87Sr/86Sr ratios (0.7045±0.0015), positive Nd(T) values (+1.3 to +2.8), and young Sm–Nd model ages (720–840 Ma). These characteristics are indicative of juvenile nature for these granites. Other Late Paleozoic to Mesozoic granites in this region also show the same features. Sr–Nd and oxygen isotopic data suggest that the magmatic evolution of the granites can be explained in terms of two-stage processes: (1) formation of parental magmas by melting of a relatively juvenile crust, which is probably a mixed lithology formed by pre-existing lower crust intruded or underplated by mantle-derived basaltic magma, and (2) extensive magmatic differentiation of the parental magmas in a slow cooling environment.
The widespread distribution of juvenile granitoids in NE China indicates a massive transfer of mantle material to the crust in a post-orogenic tectonic setting. Several recent studies have documented that juvenile granitoids of Paleozoic to Mesozoic ages are ubiquitous in the Central Asian Orogenic Belt, hence suggesting a significant growth of the continental crust in the Phanerozoic. 相似文献
3.
The Qinling Orogenic belt has been well documented that it was formed by multiple steps of convergence and subsequent collision between the North China and South China Blocks during Paleozoic and Late Triassic times. Following the collision in Late Triassic times, the whole range evolved into an intracontinental tectonic process. The geological, geophysical and geochronological data suggest that the intracontinental tectonic evolutionary history of the Qinling Orogenic Belt allow deduce three stages including strike-slip faulting during Early Jurrassic, N-S compressional deformation during Late Jurassic to Early Cretaceous and orogenic collapse during Late Cretaceous to Paleogene. The strike-slip faulting and the infills in Early Jurassic along some major boundary faults show flower structures and pull-apart basins, related to the continued compression after Late Triassic collision between the South Qinling Belt and the South China Block along the Mianlue suture. Late Jurassic to Early Cretaceous large scale of N-S compression and overthrusting progressed outwards from inner of Qinling Orogen to the North China Block and South China Block, due to the renewed southward intracontinental subduction of the North China Block beneath the Qinling Orogenic Belt and continuously northward subduction of the South China Block, respectively. After the Late Jurassic-Early Cretaceous compression and denudation, the Qinling Orogenic Belt evolved into Late Cretaceous to Paleogene orogen collapse and depression, and formed many large fault basins along the major faults. 相似文献
4.
中国东北地区显生宙花岗岩的成因一直是中亚造山带东段研究的热点之一,尤其是小兴安岭-张广才岭地区的花岗岩其成因及形成的大地构造背景一直存在较大争议。本文新获得小兴安岭-张广才岭铁力和依兰地区的二长花岗岩LA-ICP-MS锆石U-Pb年龄分别为188±1 Ma和257±3 Ma。地球化学数据显示,两地区的二长花岗岩均为Ⅰ型花岗岩并且富集大离子亲石元素(Th和U等)和轻稀土元素,亏损高场强元素(Nb和Ta等)和重稀土元素具有弧岩浆岩的地球化学特征。锆石Hf同位素数据显示,铁力地区二长花岗岩的岩浆源区可能来自于中新元古代的下地壳部分熔融。综合前人在小兴安岭-张广才岭地区已发表的花岗岩类岩石的地质年代学和地球化学数据,初步推测小兴安岭-张广才岭地区在晚古生代至中生代期间处于活动大陆边缘环境。同时,小兴安岭-张广才岭地区晚古生代至中生代的岩浆岩具有自东向西形成时代逐渐变年轻的趋势,这可能是由于东侧的牡丹江洋在晚古生代至中生代期间俯冲角度逐渐变缓造成的。 相似文献
5.
The Qinling Orogen is one of the main orogenic belts in Asia and is characterized by multi-stage orogenic processes and the development of voluminous magmatic intrusions. The results of zircon U–Pb dating indicate that granitoid magmatism in the Qinling Orogen mainly occurred in four distinct periods: the Neoproterozoic (979–711 Ma), Paleozoic (507–400 Ma), and Early (252–185 Ma) and Late (158–100 Ma) Mesozoic. The Neoproterozoic granitic magmatism in the Qinling Orogen is represented by strongly deformed S-type granites emplaced at 979–911 Ma, weakly deformed I-type granites at 894–815 Ma, and A-type granites at 759–711 Ma. They can be interpreted as the products of respectively syn-collisional, post-collisional and extensional setting, in response to the assembly and breakup of the Rodinia supercontinent. The Paleozoic magmatism can be temporally classified into three stages of 507–470 Ma, 460–422 Ma and ∼415–400 Ma. They were genetically related to the subduction of the Shangdan Ocean and subsequent collision of the southern North China Block and the South Qinling Belt. The 507–470 Ma magmatism is spatially and temporally related to ultrahigh-pressure metamorphism in the studied area. The 460–422 Ma magmatism with an extensive development in the North Qinling Belt is characterized by I-type granitoids and originated from the lower crust with the involvement of mantle-derived magma in a collisional setting. The magmatism with the formation age of ∼415–400 Ma only occurred in the middle part of the North Qinling Belt and is dominated by I-type granitoid intrusions, and probably formed in the late-stage of a collisional setting. Early Mesozoic magmatism in the study area occurred between 252 and 185 Ma, with the cluster in 225–200 Ma. It took place predominantly in the western part of the South Qinling Belt. The 250–240 Ma I-type granitoids are of small volume and show high Sr/Y ratios, and may have been formed in a continental arc setting related to subduction of the Mianlue Ocean between the South Qinling Belt and the South China Block. Voluminous late-stage (225–185 Ma) magmatism evolved from early I-type to later I-A-type granitoids associated with contemporaneous lamprophyres, representative of a transition from syn- to post-collisional setting in response to the collision between the North China and the South China blocks. Late Mesozoic (158–100 Ma) granitoids, located in the southern margin of the North China Block and the eastern part of the North Qinling Belt, are characterized by I-type, I- to A-type, and A-type granitoids that were emplaced in a post-orogenic or intraplate setting. The first three of the four periods of magmatism were associated with three important orogenic processes and the last one with intracontinental process. These suggest that the tectonic evolution of the Qinling Orogen is very complicated. 相似文献
6.
秦岭-大别新元古代-中生代沉积盆地演化 总被引：1，自引：0，他引：1
秦岭-大别造山带处于中央造山带的东部,经历了复杂的构造-沉积历史.在系统分析研究区4个二级和13个三级构造单元岩石地层、化石组合、同位素年代学及构造学等资料的基础上,划分出18个沉积盆地类型,并讨论新元古代-中生代构造-沉积演化:(1)新元古代-早古生代:商丹洋以北的北秦岭为岩浆弧和弧前盆地;南秦岭为陆内裂谷-台盆、台地-陆缘裂谷发育阶段;大别-苏鲁为陆内裂谷-台盆台地发育阶段;(2)晚古生代:北秦岭为海陆交互陆表海;勉略洋于泥盆纪开启;南秦岭为弧后陆棚与台盆台地并存发育阶段;(3)三叠纪:陆陆碰撞造山,全区进入前陆盆地发育阶段;(4)侏罗纪-白垩纪:断陷盆地和压陷盆地发育阶段. 相似文献
7.
中国南方显生宙大地构造演化简史 总被引：13，自引：3，他引：10
中国南方的构造格架以众多造山带围绕扬子克拉通分布为特征。这些造山带分别形成于古生代(华南造山带)和中—新生代(秦岭-大别山造山带、松潘-甘孜造山带、三江造山带、右江造山带和沿海造山带)。在造山带中散布着保山地块和南海地块等微陆块。本文以扬子克拉通为中心,概述了中国南方显生宙构造古地理演化的主体面貌,并归纳了其对海相烃源岩堆积的制约关系,指出制约和影响中国南方古地理演化的几个主要的构造事件为:新元古代晚期至古生代早期的大陆裂谷和被动大陆边缘形成事件,古生代中期华南造山带形成演化事件,古生代晚期张裂事件,中生代古特提斯洋闭合造山事件,侏罗纪以来的太平洋板块俯冲事件,新生代印度板块与欧亚大陆的碰撞事件等。本文还指出,上述这些事件延续的时间有限,变形强度在空间上也有差异,对于油气成藏和晚期调整的影响也会因时因地而异。具体事物具体分析才能对研究中国南方油气分布规律有所帮助。 相似文献
8.
东昆仑造山带花岗岩及地壳生长 总被引：65，自引：0，他引：65
东昆仑造山带是青藏高原内可与冈底斯相媲美的又一条巨型构造岩浆岩带。该带内的花岗岩形成可以划分为4个时段,分别与4个造山旋回相对应：前寒武纪（元古宙）;早古生代;晚古生代—早中生代;晚中生代—新生代。其中,以晚古生代—早中生代（或称华力西—印支旋回）、特别是三叠纪的花岗岩最为发育。东昆仑造山带基底主要形成于古元古代晚期。其早古生代构造-岩浆事件序列与北祁连造山带可以对比,属祁连—东昆仑加里东造山系统的一部分。到晚古生代—早中生代时东昆仑卷入古特提斯构造体制,属于古特提斯造山系统的北缘。华力西—印支是一个完整的造山旋回,与西南“三江”古特提斯的演化历史相似。昆南缝合带是当时中国南北大陆的主要构造分界线。新生代印度—欧亚大陆的碰撞,使东昆仑造山带又卷入了青藏大陆碰撞造山系统,但对东昆仑的影响是一种远程效应。
东昆仑造山带大陆地壳主要形成于古元古代晚期,但在显生宙还有新生地壳 （juvenile crust） 产生,与兴蒙、冈底斯、安第斯等造山带相似。东昆仑花岗岩带中丰富的幔源岩浆底侵作用与壳-幔源岩浆混合作用的证据,以及花岗岩类的Nd、Sr同位素成份（87Sr/ 86Sr初始值多数小于0.710;εNd（t ）值变化于－9.2和＋3.6之间）,说明
地幔物质的注入及其与地壳物质的混合,对显生宙地壳的形成演化起着重要作用,是显生宙东昆仑地壳生长的重要方式。根据花岗质寄主岩、镁铁质暗色微粒包体（MME）及底侵辉长岩的锆石SHRIMP U-Pb定年,东昆仑造山带在显生宙发生过两次大规模的底侵作用与岩浆混合作用,一次在早-中泥盆世（394~403 Ma）,另一次在中三叠世（239～242 Ma）,分别相当于加里东旋回、华力西-印支旋回的俯冲结束/碰撞开始阶段。 相似文献
9.
阿尔泰造山带花岗岩时空演变、构造环境及地壳生长意义——以中国阿尔泰为例 总被引：23，自引：0，他引：23
阿尔泰造山带横跨中、俄、哈、蒙四国边界,是中亚造山带主要组成部分,发育大量的花岗岩等侵入体。本文研究总结这些岩体的时空演变、成因类型和构造环境,并探讨其增生造山和地壳生长意义。依据锆石年龄,这些岩体可大致分为早中古生代的470～440Ma(中晚奥陶世)和425～360Ma(晚志留世—晚泥盆世)、晚古生代的355～318Ma(早石炭世)和290～270Ma(早二叠世)以及早中生代245～190Ma(中晚三叠世—早侏罗世)3个阶段5个期次,其中425～360Ma花岗岩可进一步细分为425～390Ma和380～360Ma两个峰期。早中古生代(470～360Ma)花岗岩体分布广泛,主要为钙碱性I型,多具不同程度变形,其中470～440Ma岩体变形极强(片麻岩体)。它们为同造山俯冲增生产物,形成于活动陆缘俯冲(470～440Ma)、继续俯冲弧后盆地伸展(420～390Ma)到聚合碰撞(380～360Ma)的过程中。早石炭世岩体发育于造山带南部,为不变形圆形状或不规则状,具典型碱性花岗岩特征,为晚(后)造山产物。早二叠世岩体主要发育于阿尔泰造山带南部,少量分布于造山带内部,多为圆形,不变形,少量变形岩体集中在额尔齐斯构造带内,成因类型以I、A型为特点,伴生有大量基性岩脉(体),显示为后造山底侵伸展环境。早中生代岩体为不变形圆形或不规则状,具有高分异I型和S型花岗岩特征,伴有稀有金属矿产,具有板内环境特点。花岗岩体同位素填图显示,阿尔泰中部块体岩体具有较低的εNd(t)值和老的Nd同位素模式年龄(1～1.3Ga),暗示存在古老地壳基底;由北向南εNd(t)值增高,模式年龄变年轻,显示陆壳向南生长,其中水平和垂向生长率分别为18%～28%和7%～8%。中生代时期阿尔泰造山带保留水平增生结构,没有发生大规模构造块体垂向叠覆。阿尔泰造山带经历了古陆缘构造演化,奥陶纪—志留纪陆缘俯冲,泥盆纪陆弧及陆缘边缘裂解、弧后盆地形成,晚泥盆世最终洋盆闭合及早石炭世各块体拼合的演化过程。该研究表明增生造山带中同样存在构造演化的阶段性;中亚增生造山作用不仅具有弧前增生,而且还存在陆缘裂解再拼合作用。 相似文献
10.
西秦岭楔的构造属性及其增生造山过程 总被引：27，自引：17，他引：10
西秦岭楔是叠置于早古生代造山作用基础上形成的并插入祁连和昆仑早古生代造山带内部的楔形地质体,以大面积出露三叠系并发育多条蛇绿混杂岩带、大型韧性剪切带、中生代火山-岩浆作用和斑岩-矽卡岩型矿床为典型特征,具有增生造山作用的典型特征。这些蛇绿混杂岩带和岛弧钙碱性火山-岩浆岩的形成时代均具有向南逐渐变年轻的空间演化特征,显示了特提斯洋演化过程中海沟具有向南撤退的基本特征。砂岩碎屑组成以及源区特征研究结果表明,西秦岭楔三叠系形成于活动大陆边缘,其碎屑沉积物来自于古特提斯洋北侧的增生杂岩及岛弧。丰富的岛弧钙碱性火山-岩浆岩和沉积组合以及赋存的斑岩-矽卡岩型矿床,均与东昆仑及南秦岭相一致,呈现出相似的岩石组合类型以及岩石地球化学和同位素地球化学特征。这些事实表明,三叠纪时期,东昆仑、西秦岭以及祁连造山带是一个有机整体,自西向东存在一条三叠纪增生岩浆弧。锆石Hf同位素及岩石地球化学成分结果则表明,该增生岩浆弧部分岩浆来自于俯冲增生杂岩的部分熔融。 相似文献
11.
秦岭地幔柱源岩浆活动及其动力学意义 总被引：15，自引：1，他引：15
通过秦岭不同时代玄武岩地幔源区类型的地球化学鉴别 ,揭示出北秦岭地幔柱源岩浆活动开始于古元古代 ,并至少断续延续到新元古代中晚期 ;而南秦岭地幔柱源岩浆活动则开始于中元古代晚期 ,并至少延续到新元古代之末。根据地幔柱活动中心显示出的随时间自北向南迁移的规律 ,结合该区北面的商丹洋盆打开在前 (新元古代—早古生代 ) ,南面勉略洋盆打开在后 (晚古生代 ) ,两洋盆均属于扬子陆块内部裂解类型 ,以及北秦岭于新元古代前属于扬子板块等情况 ,提出秦岭造山带发展动力学特征表现为扬子的裂解和华北的增生 ,并处于全球冈瓦纳大陆裂解和亚洲大陆增生的总动力学体系之中。 相似文献
12.
Tectonic Framework and Deep Structure of South China and Their Constraint to Oil‐Gas Field Distribution 总被引：4，自引：3，他引：1
South China could be divided into one stable craton, the Yangtze Craton (YzC), and several orogenic belts in the surrounding region, that is the Triassic Qinling-Dabie Orogenic Belt (QDOB) in the north, the Songpan-Garzê Orogenic Belt (SGOB) in the northwest, the Mesozoic-Cenozoic Three-river Orogenic Belt (TOB) in the west, the Youjiang Orogenic Belt (YOB) in the southwest, the Middle Paleozoic Huanan Orogenic Belt (HOB) in the southeast, and the Mesozoic-Cenozoic Maritime Orogenic Belt (MOB) along the coast. Seismic tomographic images reveal that the Moho depth is deeper than 40 km and the lithosphere is about 210 km thick beneath the YzC. The SGOB is characterized by thick crust (>40 km) and thin lithosphere (<150 km). The HOB, YOB and MOB have a thin crust (<40 km) and thin lithosphere (<150 km). Terrestrial heat flow survey revealed a distribution pattern with a low heat flow region in the eastern YzC and western HOB and two high heat flow regions in the TOB and MOB respectively. Such a “high-low-high” heat flow distribution pattern could have resulted from Cenozoic asthenosphere upwelling. All oil-gas fields are concentrated in the central part of the YzC. Remnant oil pools have been discovered along the southern margin of the YzC and its adjacent orogenic belts. From a viewpoint of geological and geophysical structure, regions in South China with thick lithosphere and low heat flow value, as well as weak deformation, might be the ideal region for further petroleum exploration. 相似文献
13.
兴蒙造山带正ε(Nd,t)值花岗岩的成因和大陆地壳生长 总被引：29，自引：3，他引：26
大陆地壳的生长速率和地壳生长的位置均是地球科学中的最基本的问题。现有的许多大陆地壳生长模式认为 ,90 %的大陆地壳生长于 18亿年以前 ,显生宙以来的地壳生长不到整个地壳的 10 % ,主要位于活动大陆边缘。近年来在兴蒙造山带发现大量具有新生地壳来源性质的花岗岩产生于 50 0～ 10 0Ma ,对上述传统看法提出了挑战。现有的Nd同位素资料表明 ,兴蒙造山带的显生宙花岗岩 ,不论形成于什么时代和什么构造背景 ,也不论属于何种成因类型 ,几乎都具有正ε(Nd ,t)值和年轻的Nd模式年龄tDM 。从西往东 ,随着时代逐渐变新ε(Nd ,t)值有逐渐降低的趋势。花岗岩的tDM同由蛇绿岩和岛弧杂岩记录的古亚洲洋扩张的时间基本一致。只有一些在新元古代微陆块上的花岗岩才显示负ε(Nd ,t)值和较老的tDM,反映了其源岩包括前寒武纪地壳同地幔来源物质的不同程度混合。兴蒙造山带的花岗岩具有地幔来源的ε(Nd ,t)值 ,说明这些花岗岩中有一部分 (例如加里东期和海西早期 )可能同板块俯冲作用有关 ,花岗岩的来源是被交代的地幔楔。而大面积的晚古生代—中生代花岗岩则可能是由 80 0～6 0 0Ma前俯冲的洋壳形成的新生大陆地壳在拉伸体制下部分熔融而成。如果情况是这样 ,显生宙就曾发生过大规模的地壳生长。板内岩浆活动 ,特别是 相似文献
14.
苏-查萤石矿区钾长花岗岩锆石SHRIMP年龄
及其地质意义 总被引：3，自引：2，他引：1
内蒙古苏-查萤石矿区是全球范围内最大的单一萤石矿区。萤石矿体大多呈似层状和透镜体状在下二叠统火山-沉积岩地层内产出, 并且与显生宙花岗岩类侵入岩体具有密切时空分布关系, 其中部分矿体直接出现在敖包吐花岗岩株中。本次研究主要对敖包吐岩株钾长花岗岩进行了锆石SHRIMP铀-铅同位素年龄测定, 所获同位素年龄值为(138±4)Ma, MSWD值为2.3, 属中生代燕山期。根据上述同位素年代学数值, 同时结合其他地质与地球化学证据, 可以推测, 中生代时期, 受古板块内部构造应力调整作用影响, 苏-查萤石矿区及东西两侧曾发生过强烈构造-岩浆活动, 并且形成有敖包吐花岗岩株及相关的萤石矿床。中生代燕山期花岗岩类岩浆活动不仅为萤石矿床的形成提供了物质、动力和热力来源, 而且是成矿流体对流循环的“发动机”。对比分析结果表明, 敖包吐岩体的形成时间与华北陆台中东段许多含矿花岗岩体的成岩时代大体相似, 它们很可能是地壳演化特定阶段混源(壳、幔源)岩浆活动的产物。 相似文献
15.
秦岭造山带金属成矿系统 总被引：38，自引：1，他引：38
秦岭造山带是一个多旋回复合大陆碰撞造山带，是我国重要的多金属成矿带之一，自太古代以来秦岭经历了四大构造演化阶段及多种构造体制的转化，导致了多期构造热事件和成矿作用的发生，形成了多个构造成矿旋回，为秦岭金属元素的大规模富集成矿创造了条件，根据构造，建造，成矿作用及矿床组合特征，从早到晚可将秦岭区域成矿划分为六大成矿系统。其中，中晚元古代与海相火山岩及岛弧菌浆活动有关的成矿系统，早古生代与海相火山热液有关的成矿系统，海西期与海底热液及岩浆作用有关的成矿系统及中生代与陆内造山体制构造一岩浆活动有关的成矿系统对成矿的贡献最大，成矿系统的叠加是区内大多数大型，超大型矿床形成的前提。 相似文献
16.
This study reports new zircon U–Pb ages, Lu–Hf isotope data, and oxygen isotope data for Mesozoic Mo-bearing granitoids in the eastern Xing–Meng Orogenic Belt (XMOB) of Northeast China, within the eastern Central Asian Orogenic Belt. Combining these new laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb ages with the results of previous research indicates that two stages of Mo-bearing granitoid magmatism occurred in the eastern XMOB, during the Early–Middle Jurassic (200–165 Ma) and the Early Cretaceous (ca. 111 Ma). The eastern XMOB also contains Mo-bearing granitoids with variable δ18O compositions that record variations in source oxygen isotopic compositions. Combining δ18O data with zircon U–Pb and Hf isotopic data provides evidence of the origin of these granitoids. Three types of zircon have been identified within these granitoids. Type 1 zircons formed during the Mesozoic and having high δ18O values (5.71–7.05‰) that are consistent with the compositions of magmatic zircons from the Luming, Jiapigou, and Kanchuangou areas. These zircons suggest that the Mo-bearing granitoids were derived from a source containing supracrustal materials. The type 2 zircons have extremely low and heterogeneous δ18O values (4.64–4.89‰) that are consistent with the compositions of magmatic zircons from the Jidetun and Fuanpu areas. These magmas were generated by the remelting of juvenile crustal material that was previously significantly modified by interaction with fluids. Type 3 zircons generally have mantle-like δ18O values (5.42–5.57‰), with several zircons yielding higher δ18O values, suggesting that these intrusions formed from mantle-derived magmas that assimilated and were metasomatized by crustal material. Combining these geochemical data with the geology of this region indicates that the Mo-bearing granitoids were generated as a result of subduction of the Palaeo-Pacific Plate beneath the Eurasian continent. 相似文献
17.
在全面收集中国及邻区花岗岩年代学资料的基础上,在包括俄罗斯、蒙古、吉尔吉斯坦、韩国、日本、越南等境外地区开展了野外调研, 获得大量高精度锆石U-Pb年龄,发现一些重大岩浆事件;结合系统收集的公开发表的高质量数据,建立了一些关键地区的花岗岩年代学格架;初步总结了中亚、中央、特提斯和环太平洋构造域花岗岩的时空分布及构造-岩浆演化,提供相关成矿背景,编制了四个构造域的花岗岩时空分布图。在此基础上,初步编制了亚洲花岗岩时空分布图,总结了花岗岩浆作用与构造演化的关系,为探讨亚洲大地构造演化,特别是陆块聚合过程的研究提供了依据。这是一次尝试性的较系统地论述亚洲花岗岩及构造-岩浆演化的研究。 相似文献
18.
陕西柞山盆地池沟铜钼矿区含矿岩体的锆石U-Pb年龄和岩石成因 总被引：13，自引：7，他引：6
秦岭造山带柞山盆地多处发育与晚中生代中酸性小岩体有关的铜钼矿床(点),最近在池沟深部发现了厚大的斑岩型铜矿体,但对这些小岩体的形成时代和成因的研究很少。本文选择池沟地区不同类型的花岗质岩石开展地球化学特征和锆石U-Pb测年的研究。结果表明:该区小岩体主要为闪长岩、石英闪长岩和斑状花岗岩,它们为钾质钙碱性Ⅰ型花岗质岩石。矿物学、地球化学和Sr-Nd同位素特征均暗示它们是上地幔和下地壳同熔的深熔岩浆产物。与成矿密切相关的含矿岩体LA-MC-ICPMS锆石U-Pb谐和年龄为~145Ma,结合区域地质资料和成岩成矿关系的研究,认为池沟含矿岩体形成于晚侏罗世-早白垩世,柞水盆地存在一期重要的晚侏罗世-早白垩世中酸性岩浆岩和相应的斑岩-矽卡岩铜钼金矿化,与华北地块南缘晚中生代岩体和相关的钼铅锌矿床形成于同一地质事件。 相似文献
19.
中亚造山系中南段早中生代花岗岩类时空分布特征及构造环境 总被引：8，自引：0，他引：8
依据锆石U-Pb年龄,中亚造山系中南段早中生代花岗岩类大致可以划分出早中三叠世(251～227Ma)和晚三叠世—早侏罗世(226～195Ma)两个阶段。早中三叠世花岗岩类,主要分布于东天山造山带中东部、北山造山带中北部、中蒙古地块、阿尔泰造山带西段及内蒙古-吉林造山带中西部地区,多沿板块缝合带及附近展布,具有准铝质-弱过铝质的钙碱性-高钾钙碱性或弱碱性花岗岩的特点,I型、S型和A型或I-A型花岗岩均有出露,且同期的超镁铁质-镁铁质岩少见。晚三叠世—早侏罗世花岗岩类,较广泛分布于全区各造山带,具有准铝质-弱过铝质的高钾钙碱性-碱性花岗岩的特点,大都为A型和I-A型花岗岩,部分具有高分异Ⅰ型花岗岩的特点,且同期的超镁铁质-镁铁质岩较发育。早期花岗岩类的稀土元素总量(ΣREE)高于晚期,但晚期较早期具显著负铕异常,晚期花岗岩Ba、Nb、Sr、P和Ti的亏损程度较早期更明显一些。花岗岩Sr-Nd同位素特征显示,华北北缘具有非常低的εNd(t)值(-19.6～-5.4)和老的tDM值(1.23～2.09Ga),以古老陆壳为其主要源区;北蒙古-西外贝加尔造山带和内蒙古-吉林造山带主体以年轻物源为主;中蒙古地块、阿尔泰造山带、东天山造山带和北山造山带在以古老微陆块为花岗岩源区的构造背景下,有部分年轻幔源组分的贡献,总体显示出早期以壳源和幔源的双源为特点,晚期以幔源为主,从早期到晚期有年轻幔源组分递增的趋势。大量新生地壳主要分布在鄂霍茨克带及其邻区,但在一些老的微陆块上,后造山或后碰撞阶段也有较多年轻幔源岩浆的底侵而导致地壳垂向生长。早中三叠世花岗岩类在中亚造山系西部地区为后造山构造背景,东部地区为同造山作用的晚期阶段;晚三叠世—早侏罗世花岗岩类为后造山或非造山或板内伸展构造背景。 相似文献
20.
东昆仑造山带位于中央造山系西段,在长期的地质演化过程中构造岩浆活动频繁,其中晚古生代—早中生代岩浆活动与成矿关系最为密切。本文系统总结了东昆仑造山带晚古生代—早中生代岩浆岩的分布、演化和成因,对典型矿床的地质特征进行分析,探讨东昆仑东段晚古生代—早中生代构造岩浆演化与成矿作用的联系。东昆仑晚古生代—早中生代构造岩浆演化可分为俯冲阶段(277~240 Ma)、同碰撞阶段(240~230 Ma)和后碰撞阶段(230~200 Ma),壳幔岩浆混合作用贯穿于古特提斯构造演化全过程。镁铁质岩浆岩主体为受俯冲流体交代的地幔部分熔融,花岗质岩浆岩主体为幔源岩浆底侵镁铁质下地壳部分熔融形成。东昆仑造山带东段俯冲阶段壳幔岩浆混合作用不仅带来成矿物质,使部分元素含量增高,还带来热源;经过成矿流体物理化学条件改变,导致大量矿物质沉淀,形成矿床,主要成矿金属组合为Cu、Mo、Au,矿床规模相对较小;同碰撞阶段由于受到挤压应力,岩浆岩出露较少,矿床多沿大型断裂带分布,主要成矿金属组合也以Cu、Mo、Au为主;后碰撞阶段由于岩石圈地幔拆沉,东昆仑整体处于拉张环境,为地幔物质参与成矿和成矿流体运移提供了通道。特别是同碰撞和后碰撞的转换阶段,是东昆仑造山带东段晚古生代—早中生代的主要成矿期,主要成矿金属组合为Cu、Pb、Zn、Fe。 相似文献