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1.
湖南千里山花岗岩体的Nd-Sr同位素及岩石成因研究   总被引:24,自引:5,他引:24  
本文利用Rb-Sr等时线方法测得第一阶段似斑状黑云母花岗岩、第二阶段等粒黑云母花岗岩和第三阶段花岗斑岩的成岩年龄分别为(152士9)×l06 a、(137士7)×l06 a ~(136士6)×106 a和(131士1)×l06 a。Sr-Nd同位素资料表明各阶段花岗质岩石均基本上源于地壳物质的重熔。与钨多金属矿化有关的似斑状黑云母花岗岩和等粒黑云母花岗岩属同一岩浆体系分异演化的产物,其钕模式年龄(tDM= 2307×l06 a)反映出成岩物质来自早元古宙地层的重熔。与铅,锌一银矿化有关的花岗斑岩的钕模式年龄(tDM= 1284×l06 ~ 1578×l06 a)示意出其成岩物质来自中元古宙地层的重熔。  相似文献   

2.
华南诸广山复式岩体中段花岗岩的碱交代蚀变   总被引:8,自引:0,他引:8  
诸广山复式花岗岩体中段某大型铀矿田中的部分花岗岩广泛发育碱交代蚀变作用。据对313个碱交代蚀变花岗岩样品的岩石化学分析资料及岩相学研究结果表明,该地碱交代蚀变是以钠长石化为主的多阶段钾、钠叠加交代(即混合交代),蚀变强度大多较弱,局部可较强并生成二长石岩、钠长石岩等交代蚀变岩。测得该碱交代蚀变岩石的Rb-Sr等时线年龄为132.1±5.8Ma,在时序上它与主体侵入的似斑状黑云母花岗岩(Rb-Sr等时线成岩年龄为215.2±6.3Ma)、补体侵入的细粒少斑黑云母花岗岩(测得Rb-Sr等时线成岩年龄为155.2±5.45Ma)构成一连续演化序列,推测碱质可能源自该产铀花岗岩岩浆演化钠转折分异阶段的产物;该蚀变岩属铀成矿前已遭剥蚀的钨、锡矿化矿根相,成为随后工业铀矿化(U-Pb法测得成矿年龄为103.2±0.6Ma)的有利围岩。  相似文献   

3.
广东阳春盆地花岗岩类同位素,微量元素地球化学研究   总被引:2,自引:0,他引:2  
对阳春盆地3个花岗岩类岩体进行了年龄测定,岗尾岩体和锡山岩体的黑云母K-Ar稀释法年龄平均值分别为156×10^6和76×10^6a,石录岩体花岗闪长岩中黑云母,钾长石和斜长石等单矿物^40Ar/^39Ar坪年龄平均值为100×10^6a,马山岩体,岗尾央体和石录岩体的锶同位素初始比值分别为0.7040,0.7064和0.7089,它们均属于壳幔混合型花岗岩类,根据微量元素判别,锡山岩体花岗岩是壳  相似文献   

4.
广东东镇岩体微区^40Ar/^39Ar年龄及其意义   总被引:3,自引:0,他引:3  
采用激光显微探针^40Ar/^39Ar测年技术(简称微区^40Ar/^39Ar法)对广东云开地区东镇岩体含眼球体的片麻状花岗质岩石中单矿物作了同位素年龄测定,获得眼球体内核中的巨晶状钾长石年龄(419.40±4.37)×10^6a。眼球体角缘中重结晶微粒状钾长石年龄(272.63±3.13)×10^6a,眼球体外壳中的强应变长条纹黑云母年龄(177.84±2.29)×10^a。暗色条带中的弱应变板  相似文献   

5.
本文给出的滹沱群下亚群青石村组玄武岩Rb-Sr、Sm-Nd全岩等时线年龄为2045.8±17和2369±30Ma(Z),角门石40Ar-39Ar坪年龄和最高视年龄为1364±19和1932±19Ma(1);中亚群河边村组玄武岩Rb-Sr全岩等时线年龄图的投点呈完全离散状,Sm-Nd全岩等时线年龄为2322±31Ma(2),角门石40Ar-39Ar坪年龄和最高视年龄为1360和1742±17Ma(1)。根据上述Rb-Sr、Sm-Nd数据与已知青石村组、河边村组单颗粒锆石U-Pb法确定的成岩年龄2450±10和2400±20Ma(2)的明显差别,40Ar-39Ar均揭示为较典型受扰动的年龄谱和较发育的透人性构造、晚期岩脉等地质证据,认为Rb-Sr、Sm-Nd是重设的同位素体系。  相似文献   

6.
新疆阿尔曼太蛇绿岩时代的Nd—Sr同位素地质研究   总被引:15,自引:7,他引:15  
黄萱  金成伟 《岩石学报》1997,13(1):85-91
本文通过测定采自新疆阿尔曼太兔子泉一带蛇绿岩的堆晶辉长岩、辉绿岩和安山玢岩,获得Sm-Nd等时年龄为561±41Ma,εNd(t)=6.1,Rb-Sr等时年龄为392±17Ma,(87Sr/86Sr)i=0.7041,前者为蛇绿岩的形成时代,后者为蛇绿岩遭受后期变质作用的时间。札河坝-阿尔曼太蛇绿岩的形成环境可能是古亚洲洋向南俯冲引起的弧后盆地  相似文献   

7.
扬子地台西缘富碱花岗斑岩特征及成因探讨   总被引:12,自引:2,他引:12  
本详细研究了扬子地台西缘富碱花花岗斑岩的岩石学、矿物学、稀土元素地球化学和Sr、S、Pb同位素的特征,指出富碱花岗斑岩侵入年代新,同其同位素年龄范围为35-52Ma,属于喜马拉雅期产物,岩石主要成分钾长石(35%-45%)、斜长石(15%±)、黑云母(10%±)和角闪石(5%±)。  相似文献   

8.
福建省花岗岩类Nd-Sr同位素特征及其意义   总被引:19,自引:8,他引:11  
凌洪飞  沈渭洲 《岩石学报》1999,15(2):255-262
本文报道了福建省范围内前人分析数据稀疏或空白区域内的18个古生代-中生代花岗岩体的Nd、Sr同位素组成:εNd(t)=-3.6~-16.4,(87Sr/86Sr)i=0.7055~0.7318,tDM=1.2~2.3Ga。结合前人分析数据,区分出三个地域区带:福安-南靖断裂以东的沿海带:εNd(t)=-1.5~-6.8,(87Sr/86Sr)i=0.7056~0.7099,tDM=1.1~1.45Ga,弧后伸展构造背景下的幔-壳岩浆混合是该带花岗岩的主要成岩方式;福安-南靖断裂以西的内陆区域:εNd(t)=-4.0~-16.4,(87Sr/86Sr)i=0.7064~0.7410,tDM=1.3~2.3,其中加里东-印支期花岗岩主要由与麻源群相当之地壳物质部分熔融形成,而燕山期花岗岩,一部分由与麻源群相当或较年轻的地壳物质部分熔融产生,也有一部分可能由壳-幔岩浆混合形成;福建省南部的纬向带:εNd(t)=-3.6~-7.5,(87Sr/86Sr)i=0.7055~0.7099,tDM=1.2~1.55,同位素特征与沿海带相似,但该带构造拉张发育时间较沿海带略早  相似文献   

9.
香港中生代火成岩U—Pb法年龄测定   总被引:1,自引:0,他引:1  
Davis  DW 《广东地质》1998,13(3):59-68
香港中生代侵入岩和火山岩22个锆石和独居石新的U-Pb年龄,揭示了中侏罗世至早白垩世火山-深成作用分为4期,(164.6±0.2)×10^6~(159.3±0.3)×10^6a,(146.6±0.2)×10^6~(146.2±0.2)×10^6a,(143.7±0.3)×10^6~(142.5±0.3)×10^6a,(140.9±0.2)×10^6~(140.4±0.2)×10^6a。从最早知道的  相似文献   

10.
追索北峪奥长花岗岩与围岩接触关系,发现北峪奥长花岗岩已侵入于围地层中,表明其为早元古代岩浆型侵入体。使用全岩Rb-Sr等时线方法测定北峪奥长花岗岩时代,获得的年龄为2107±59Ma(2σ),由此推断北峪岩体成岩时代为2100Ma,代表了本区绛县运动岩浆成事件年龄。  相似文献   

11.
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.  相似文献   

12.
Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931.  相似文献   

13.
PALEONTOLOGY     
正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.)  相似文献   

14.
正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.)  相似文献   

15.
正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.)  相似文献   

16.
PETROLOGY     
正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus.,  相似文献   

17.
正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an  相似文献   

18.
正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of  相似文献   

19.
正20140582 Fang Xisheng(Key Lab.of Marine Sedimentology and Environmental Geology,First Institute of Oceanography,State Oceanic Administration,Qingdao 266061,China);Shi Xuefa Mineralogy of Surface Sediment in the Eastern Area off the Ryukyu Islands and Its Geological Significance(Marine Geology Quaternary Geology,ISSN0256-1492,CN37  相似文献   

20.
正20141810 Bian Yumei(Geological Environmental Monitoring Center of Liaoning Province,Shenyang 110032,China);Zhang Jing Zoning Haicheng,Liaoning Province,by GeoHazard Risk and Geo-Hazard Assessment(Journal of Geological Hazards and Environment Preservation,ISSN1006-4362,CN51-1467/P,24(3),2013,p.5-9,2 illus.,tables,refs.)  相似文献   

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