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1.
对新疆西昆仑黑石北湖地区巴颜喀拉山群碎屑岩系安山质沉凝灰岩夹层的锆石进行LA-ICP-MS U-Pb同位素年龄测定。研究结果表明,在去掉出现明显U亏损的4个点后,剩下的10个测点206Pb/238U年龄加权平均值为252.9±9.1 Ma,代表安山质沉凝灰岩岩浆物质的形成时间,时代为晚二叠世—早三叠世。但沉凝灰岩的形成时间一般晚于喷发时间,因此该火山岩夹层的形成时代为早三叠世。通过对该套地层时代的讨论,为本区进一步研究巴颜喀拉山群的物质组成及形成时代提供了新的证据。 相似文献
2.
为了精确厘定莲花山铜矿的成矿时代,在前人研究的基础上,开展了与成矿关系密切的花岗闪长斑岩锆石U-Pb定年测定。实验结果共获得4组年龄数据,第1组有1个锆石,206Pb/238U年龄为343Ma±2Ma;第2组1个锆石,206Pb/238U年龄为264Ma±2Ma;第3组有1个锆石,206Pb/238U年龄为256Ma±2Ma;第4组有17个锆石,206Pb/238U年龄在240~249Ma之间,206Pb/238U年龄加权平均值为246.4Ma±1.2Ma(N=17)。结合所测锆石的CL图像特征,确定花岗闪长斑岩就位发生在晚二叠世—早三叠世。 相似文献
3.
对黑龙江省东部敦—密断裂以南的太平岭边缘隆起带上的黄松群杨木组石榴黑云片岩和阎王殿组黑云石英片岩进行了锆石LA-ICP-MS U-Pb测年,结果表明:杨木组石榴黑云片岩中锆石~(206)Pb/~(238)U加权平均峰值年龄分别为281.8 Ma、317.2 Ma、424.7 Ma、529.3 Ma;阎王殿组黑云石英片岩中锆石~(206)Pb/~(238)U加权平均峰值年龄分别为310.4 Ma、384.4 Ma、484.7 Ma;两个组所获得的最年轻的锆石~(206)Pb/~(238)U年龄分别为280±4 Ma和285±8 Ma。此外,前人对黄松群研究结果表明其变质作用时代为晚二叠世—早三叠世。因此,黄松群时代为二叠纪,海西期和加里东期岩浆岩构成了黄松群沉积物源的主体。 相似文献
4.
东昆仑早古生代花岗岩锆石U-Pb年龄及其地质意义 总被引：5，自引：0，他引：5
应用激光烧蚀多接收器电感耦合等离子体质谱(LA-MC-ICPMS)方法,对东昆仑五龙沟地区花岗岩样品进行了锆石 U-Pb 定年研究。结果表明,黄龙沟中部的糜棱岩化二长花岗岩(B20-14)中岩浆锆石206Pb/238U年龄平均值为(417.7±2.0) Ma,黄龙沟上部的糜棱岩化二长花岗岩(B21-2)中岩浆锆石206Pb/238U年龄平均值为(419.7±2.3) Ma,深水潭粗中粒二长花岗岩(B20-8)中岩浆锆石206Pb/238U 年龄平均值为(419.9±2.0) Ma,红旗沟中部的粗中粒二长花岗岩(B25-9)岩浆锆石206Pb/238U年龄平均值为(419.0±2.0) Ma。它们代表了五龙沟地区所研究花岗岩的形成年龄,其形成时代均为晚志留世,记录了东昆仑早古生代的岩浆活动。本文获得的东昆仑五龙沟地区的晚志留世花岗岩可能与东昆仑早古生代洋盆闭合后的碰撞造山作用有关。花岗岩中1861 Ma、1666 Ma古元古代继承锆石的发现,表明东昆仑造山带的基底物质为古元古代。 相似文献
5.
6.
延边地区五道沟群变质英安岩的锆石SHRIMP U-Pb年龄及其地质意义 总被引：3，自引：0，他引：3
延边地区五道沟群变质英安岩中的锆石呈自形-半自形晶,具有较高的Th/U比值(0.28～0.81),表明为岩浆成因。定年结果表明,变质英安岩中锆石具有两组年龄。其中,10个测点的206Pb/238U年龄为(265±5)～(291±5)Ma,其加权平均年龄为(274±7)Ma(MSWD=3.4);另一组3颗锆石的206Pb/238U的加权平均年龄为(323±37)Ma(MSWD=3.6)。前者应代表变质英安岩原岩的形成时代,即早二叠世;后者应代表捕获锆石的年龄。结合最新定年结果,可以认为延边地区五道沟群的形成时代为早二叠世,它们与青龙村群一起,共同构成了晚古生代大陆边缘火山-沉积建造。 相似文献
7.
为探讨滇东南瑶山群的原岩年龄以及后期经历的岩浆-变质-构造事件年龄,开展了SHRIMP锆石U-Pb定年研究。结果表明,阴极发光(CL)分析和光学显微分析显示瑶山群的锆石组成比较复杂,可以分为继承锆石、变质锆石、深熔锆石/岩浆锆石等几大类。除少量测点207Pb/206Pb年龄为新元古代外,继承锆石206Pb/238 U表面年龄变化范围集中在235±1.7Ma~261±3.6Ma,加权平均值为250.8±9.8Ma(N=4,MSWD=4.1);深熔/岩浆锆石206Pb/238 U表面年龄显示出~85Ma和~75Ma两个峰值;变质增生锆石206Pb/238 U表面年龄为49~30Ma,且主要集中在32Ma、37Ma和42Ma左右。结合区域地质情况,初步推测:250.8±9.8Ma的继承锆石峰值年龄表明,瑶山群主体的原岩时代可能不早于二叠纪;变质锆石、深熔锆石/岩浆锆石的206Pb/238 U表面年龄可分为~85Ma、~75Ma、~42Ma、~37Ma和~32Ma等5组,可能代表了红河断裂南段自燕山晚期以来5期较强烈构造-岩浆-变质事件的时限。 相似文献
8.
对伊通地区的放牛沟火山岩,以及后期侵入该火山岩的后庙岭花岗质侵入体进行了LA-ICP-MS锆石U-Pb年代学研究。3个样品中的锆石均呈自形-半自形晶,CL图像显示出明显的岩浆振荡生长环带,结合大多数锆石具有较高的Th/U比值(0.23~3.55),暗示了它们的岩浆成因。放牛沟火山岩由变玄武安山岩和变安山岩组成,其中变安山岩样品中锆石22个测点的~(206)Pb/~(238)U年龄加权平均值分为3组:420±4 Ma,402±3 Ma及280±1 Ma,其中280±1 Ma代表了安山岩的形成年龄;变玄武安山岩样品中锆石30个测点的~(206)Pb/~(238)U年龄加权平均值分为两组:401±1 Ma及279±1 Ma,后者代表了玄武安山岩的形成年龄;后庙岭花岗质侵入体中锆石18个测点的~(206)Pb/~(238)U年龄加权平均值为256±2 Ma。上述锆石U-Pb定年结果表明,放牛沟火山岩形成于早二叠世,而非前人认为的早古生代。对后庙岭侵入体的定年结果,进一步暗示放牛沟多金属硫铁矿床的成矿时代为二叠纪。 相似文献
9.
利用长安大学成矿作用及其动力学实验室Agilent 7700X四极杆等离子体质谱(ICP-MS)和Photo Machines Analyte Excite 193nm激光,在激光频率为5Hz,束斑直径为35μm条件下,对91500、GJ-1、Ple?ovice和Qinghu 4个标准锆石进行了原位微区U-Pb同位素和微量元素测定。结果显示,91500标准锆石20个测试点的~(206)Pb/~(238)U年龄范围为1059~1070Ma,~(206)Pb/~(238)U年龄加权平均值为1063.8±6.6Ma;GJ-1标准锆石28个测试点的~(206)Pb/~(238)U年龄范围为601~610Ma,~(206)Pb/~(238)U年龄加权平均值为605.4±3.0Ma;Ple?ovice标准锆石28个测试点的~(206)Pb/~(238)U年龄范围为336~341Ma,~(206)Pb/~(238)U年龄加权平均值为338.8±1.4Ma;Qinghu标准锆石40个测试点的~(206)Pb/~(238)U年龄范围为158~165Ma,~(206)Pb/~(238)U年龄加权平均值为159.9±0.7Ma。上述结果表明,91500、GJ-1、Ple?ovice和Qinghu 4个标准锆石的~(206)Pb/~(238)U年龄都在误差范围内,且年龄加权平均值与前人报道的年龄在误差范围内一致。同时,4个标准锆石的微量元素结果基本落在前人文献报道的范围内。从4个标准锆石的稀土元素球粒陨石标准化曲线可以看出,稀土元素的相对含量较准确。以上结果表明,建立的测试方法实现了对锆石原位微区U-Pb定年及微量元素的同时测定,分析数据结果准确、可靠。 相似文献
10.
广西苍梧县宝山矿床位于大瑶山隆起区的东南部,是一个与石英斑岩有关的铜多金属矿床。本文对该矿区内花岗闪长岩、细粒花岗岩和石英斑岩进行了单颗粒锆石LA-ICP-MS U-Pb测年,获得了3件花岗闪长岩的~(206)Pb/~(238)U加权平均年龄分别为433.7±1.2 Ma、435.0±1.2 Ma和449.7±2.3 Ma;1件细粒花岗岩的~(206)Pb/~(238)U加权平均年龄为100.4±0.5 Ma,2件石英斑岩样品的~(206)Pb/~(238)U加权平均年龄分别为95.4±0.7 Ma和92.5±0.5 Ma。本文认为,宝山矿区存在晚奥陶世、早志留世、早白垩世晚期和晚白垩世早期等多期岩浆活动,与成矿有关的石英斑岩锆石U-Pb年龄揭示宝山铜铅锌多金属矿床形成于晚白垩世早期。这些高精度花岗岩锆石U-Pb测年数据为进一步深入研究大瑶山地区的岩浆活动及其成矿作用提供了重要的年代学依据。 相似文献
11.
Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
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.
Inter-regional correlation of transgressions and regressions in the Cretaceous period 总被引：1，自引：0，他引：1
T. Matsumoto 《Cretaceous Research》1980,1(4):359-373
Well investigated platforms have been selected in each continent, and the history of Cretaceous transgressions and regressions there is concisely reviewed from the available evidence. The factual records have been summarized into a diagram and the timing of the events correlated between distant as well as adjoining areas.On a global scale, major transgressions were stepwise enlarged in space and time from the Neocomian, via Aptian-Albian, to the Late Cretaceous, and the post-Cretaceous regression was very remarkable. Minor cycles of transgression-regression were not always synchronous between different areas. Some of them were, however, nearly synchronous between the areas facing the same ocean.Tectono-eustasy may have been the main cause of the phenomena of transgression-regression, but certain kinds of other tectonic movements which affected even the so-called stable platforms were also responsible for the phenomena. The combined effects of various causes may have been unusual in the Cretaceous, since it was a period of global tectonic activity. The slowing down of this activity followed by readjustments may have been the cause of the global regression at the end of the Cretaceous. 相似文献
13.
The Afyon stratovolcano exhibits lamprophyric rocks, emplaced as hydrovolcanic products, aphanitic lava flows and dyke intrusions, during the final stages of volcanic activity. Most of the Afyon volcanics belong to the silica-saturated alkaline suite, as potassic trachyandesites and trachytes, while the products of the latest activity are lamproitic lamprophyres (jumillite, orendite, verite, fitztroyite) and alkaline lamprophyres (campto-sannaite, sannaite, hyalo-monchiquite, analcime–monchiquite). Afyon lamprophyres exhibit LILE and Zr enrichments, related to mantle metasomatism. 相似文献
14.
正20140751 Guo Xincheng(Geological Party,BGMRED of Xinjiang,Changji 831100,China);Zheng Yuzhuang Determination and Geological Significance of the Mesoarchean Craton in Western Kunlun Mountains,Xinjiang,China(Geological Review,ISSN0371-5736,CN11-1952/P,59(3),2013,p.401-412,8 相似文献
15.
正20141058 Chen Ling(Key Laboratory of Mathematical Geology of Sichuan Province,Chengdu University of Technology,Chengdu610059,China);Guo Ke Study of Geochemical Ore-Forming Anomaly Identification Based on the Theory of Blind Source Separation(Geosci- 相似文献
16.
正20141334 Chen Kun(Institute of Geophysics,China Earthquake Administration,Beijing100081,China);Yu Yanxiang Shakemap of Peak Ground Acceleration with Bias Correction for the Lushan,Sichuan Earthquake on April20,2013(Seismology and Geology,ISSN0253-4967,CN11-2192/P,35(3),2013,p.627-633,2 illus.,1 table,9 refs.)Key words:great earthquakes,Sichuan Province 相似文献
17.
正20141624 Cai Xiongfei(Key Laboratory of Geobiology and Environmental Geology,Ministry of Education,China University of Geosciences,Wuhan 430074,China);Yang Jie A Restudy of the Upper Sinian Zhengmuguan and Tuerkeng Formations in the Helan Mountains(Journal of Stratigraphy,ISSN0253-4959CN32-1187/P,37(3),2013,p.377-386,5 illus.,2 tables,10 refs.) 相似文献
18.
正20142263Lü Shaojun(Geological Survey of Jiangxi Province,Nanchang 330030,China)Early-Middle Permian Biostratigraphical Characteristics in Qiangduo Area,Tibet(Resources SurveyEnvironment,ISSN1671-4814,CN32-1640/N,34(4),2013,p.221-227,2illus.,2tables,22refs.)Key words:biostratigraphy,Lower Permian,Middle Permian,Tibet 相似文献
19.
正20142560Hu Hongxia(Regional Geological and Mineral Resources Survey of Jilin Province,Changchun 130022,China);Dai Lixia Application of GIS Map Projection Transformation in Geological Work(Jilin Geology,ISSN1001-2427,CN22-1099/P,32(4),2013,p.160-163,4illus.,2refs.) 相似文献
20.
正20140692 Duo Tianhui(No.402 Geological Team,Exploration of Geology and Mineral Resources of Sichuan Authority,Chengdu611730,China);Wang Yongli Computer Simulation of Neptunium Existing Forms in the Groundwater(Computing Techniques for Geophysical and Geochemical Exploration,ISSN1001-1749,CN51-1242/P,35(3), 相似文献