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1.
闽西南玮埔岩体和赣南菖蒲混合岩锆石La ICPMS U-Pb年代学   总被引:3,自引:0,他引:3  
闽西玮埔岩体和赣南菖蒲混合岩位于武夷山构造带南部地区。对NNE向展布的闽西玮埔岩体两个样品进行了锆石LaICPMS U-Pb 测年,获得的年龄为447.1±4.7Ma和440.8±3.4Ma,证明这个岩体不是原来认为的印支期花岗岩,而属于加里东岩体。赣南菖蒲混合岩发育于罗浮岩体的北侧,早期将罗浮岩体归于燕山早期岩体。对混合岩进行的锆石LaICPMS U-Pb 测年,获得的年龄为445.9±3.8Ma,确定这个岩体为加里东期。这些新的高精度年龄学数据为武夷山加里东构造运动时限和性质提供了精确约束。  相似文献   

2.
延边花岗岩是中国东北巨型花岗岩省的一部分.传统观点认为,该区花岗岩主要形成于古生代.但高精度的单颗粒锆石U-Pb定年显示,曾被认为是早海西期的棉田岩体和仲坪岩体形成于中生代,其侵位年龄分别为189±1 Ma、1 29±2 Ma,而不是以前认为的晚古生代.这一年代学结果同时还显示,两岩体是两期岩浆活动的产物,而并不是传统观点所认为的同源岩浆演化的产物.结合从延边地区部分原加里东期花岗岩中获得的中生代年代数据,认为华北地台与北侧佳木斯地块一兴凯地块间拼合历史的传统模式需要进一步修正.  相似文献   

3.
湖南九嶷山复式花岗岩体SHRIMP锆石定年及其地质意义   总被引:42,自引:11,他引:42  
应用SHRIMP锆石U-Pb法获得九嶷山复式花岗岩中的主要岩体形成年龄为:雪花顶花岗岩(432±21)Ma、金鸡岭花岗岩(156±2)Ma、砂子岭花岗岩(157±1)Ma和西山火山-侵入杂岩(156±2)Ma。结果显示砂子岭岩体属燕山早期而非印支期;西山火山-侵入杂岩属燕山早期而非燕山晚期。花岗岩中继承锆石复杂,其形成时代为1579Ma、2108Ma和2669Ma,提供了九嶷山地区存在古-中元古代,甚至太古代基底的年龄信息。新元古代(912Ma)锆石的大量出现为扬子陆块和华夏陆块碰撞带通过本区的认识提供了一个间接证据。  相似文献   

4.
河北大庙斜长岩杂岩体锆石U-Pb年龄及其地质意义   总被引:25,自引:21,他引:25  
河北承德大庙斜长岩杂岩体是我国唯一的岩体型斜长岩。为了确定杂岩体的形成时代,作者从杂岩体主要组成岩石——苏长岩、纹长二长岩中选取锆石作U-Pb年龄测定,所获得的结晶年龄分别是1693±7 Ma、1715±6 Ma。这些锆石U-Pb年龄数据说明,大庙斜长岩杂岩体的侵位至少持续了约20 Ma。大庙斜长岩杂岩体和密云奥长环斑花岗岩、长城系大红峪组钾质火山岩,以及广泛发育的基性岩墙群一起可能代表华北陆块1750~1650 Ma大陆裂解事件的岩浆作用产物。  相似文献   

5.
北祁连西段花岗质岩体的锆石U—Pb年龄报道   总被引:14,自引:0,他引:14  
通过对北祁连西段野牛滩花岗质岩体中花岗闪长岩和黑云母花岗岩的锆石U-Pb测年,获得206Pb/238U表面年龄统计权重平均值为459.6±2.5Ma,表明其形成于板块俯冲晚期。与之有关的塔儿沟和小柳沟是世界上形成于板块俯冲环境为数不多的大型钨矿床。黑云母花岗岩的锆石U-Pb不一致曲线的下交点年龄为183.1±3.8Ma可能示意北祁连山地区叠加有燕山期地质事件。  相似文献   

6.
南岭东段龙源坝复式岩体La-ICP-MS锆石U-Pb年龄及其地质意义   总被引:19,自引:0,他引:19  
龙源坝岩体是南岭花岗岩体群的一个重要组成部分,位于南岭东段,研究程度十分薄弱,至今未见可靠的同位素年龄报道。本文在运用阴极发光技术对岩体中的锆石进行细致的内部结构分析的基础上,利用La-ICP-MS锆石U-Pb原位定年方法进行了同位素年龄测定。结果表明,龙源坝岩体是一个印支期—燕山期多期次岩浆侵入形成的复式岩体,其中主体形成于印支期,尤其是印支早期。印支早期花岗岩的单颗粒锆石U-Pb年龄为241.0±5.9Ma和241.0±1.3Ma(两个样品),印支晚期花岗岩为210.9±3.8Ma,燕山期正长岩为149.4±1.2Ma。龙源坝岩体在时代和成因上不同于其东侧的陂头岩体,但相同于北侧的诸广山岩体有亲缘关系,因此在探讨该区的铀成矿前景时,应把诸广山与龙源坝两岩体整合起来考虑,并加强对龙源坝岩体的铀矿找矿工作。  相似文献   

7.
江西武山和永平铜矿含矿花岗质岩体锆石SIMS U-Pb年代学   总被引:38,自引:2,他引:38  
江西武山和永平铜矿床是长江中下游金属成矿带中的两个重要矿床。对武山铜矿的花岗闪长斑岩和永平铜矿的花岗斑岩中锆石分别进行了离子探针(SIMS)U-Pb定年研究,发现两个矿区的锆石年龄可分作两期,武山铜矿含矿岩体锆石206Pb/238U年龄分别为145±3.9Ma和121±2.5Ma,永平铜矿含矿岩体锆石206Pb/238U年龄分别为160±2.3Ma和135±7.4Ma。这两期不同的年龄可能反映了锆石在岩浆侵位时的结晶年龄和后期热液蚀变作用的年龄。因此确定武山铜矿花岗质岩体的侵位年龄为145Ma,永平铜矿花岗质岩体的侵位年龄为160Ma。该年龄可能也反映了这两个矿床中与燕山期岩浆侵入有关的矽卡岩型矿床和斑岩型矿床的形成时代。  相似文献   

8.
周丽云  王瑜  王娜 《地质通报》2015,34(203):400-418
分布于中国东北完达山地区的饶河花岗岩岩体中暗色矿物和斑晶钾长石定向排列,呈北北东走向,其中透镜状闪长质捕掳体近水平排列,局部具有左行剪切的特点。岩体中发育石香肠状石英脉,表明岩体在侵位过程中受到左行剪切作用的影响或制约。对出露的花岗岩进行LA-ICP-MS锆石U-Pb定年,获得年龄121±1Ma和119±1Ma,表明该岩浆流动形成于早白垩世。同时对围岩辉长岩、侵入岩体中的正长岩脉和辉绿岩脉进行锆石U-Pb年龄分析,分别获得160±1Ma、109±2Ma、124±1Ma的年龄结果。根据各样品中继承锆石的特征,围岩辉长岩的年龄数据很集中,不存在古老锆石的年龄信息。岩浆流动岩体及岩脉中都有太古宙、元古宙等各时代的锆石年龄数据,可能表明完达山地区在约120Ma之前已完成古太平洋板块的俯冲拼贴,饶河岩体形成于走滑环境下的陆内变形,为同构造侵入岩。  相似文献   

9.
陕西柞水地区小茅岭复式岩体东段LA-ICP-MS锆石U-Pb定年   总被引:1,自引:0,他引:1  
小茅岭复式岩体东段主要由早期宋家屋场蚀变角闪辉绿(辉长)岩体和晚期迷魂阵蚀变闪长岩体、磨沟峡蚀变石英闪长岩体、叶家湾蚀变二长闪长岩体组成。经LA-ICP-MS锆石U-Pb同位素测年,分别获得宋家屋场岩体侵位年龄864.4Ma±1.7Ma,迷魂阵岩体846.7Ma±2.7Ma,磨沟峡岩体为859.4Ma ±1.7Ma,叶家湾岩体861.1Ma±1.8Ma,确证该复式岩体形成于新元古代。鉴于在小茅岭-陡岭隆起带的早前寒武系变质岩中曾获得与北秦岭造山事件(1000~848Ma)相一致的变质年龄,结合该复式岩体自身的特征,认为小茅岭复式岩体东段形成于后造山应力松弛的构造环境。  相似文献   

10.
内蒙古达茂旗花岗岩类LA-ICP-MS 锆石U-Pb年龄及其地质意义   总被引:2,自引:1,他引:1  
冯丽霞  张志诚  韩宝福  任荣  李建锋  苏犁 《地质通报》2013,32(11):1737-1748
对内蒙古达茂旗北部构造单元的巴特敖包岛弧带2个花岗闪长岩岩体样品和南部构造单元一个花岗岩岩体的2件样品进行了LA-ICP-MS锆石U-Pb定年。北部构造单元采自2个花岗闪长岩岩体的样品锆石206Pb/238U年龄分别为468Ma±2Ma和452Ma±3Ma,代表了这2个岩体的侵位时间,表明古亚洲洋向华北克拉通之下俯冲不晚于468Ma±2Ma;南部构造单元采自同一花岗岩岩体的2件样品获得的锆石206Pb/238U年龄分别为268Ma±2Ma和264Ma±2Ma,和该单元西部岩体已有的锆石年龄相符。这为华北克拉通北缘岩浆作用研究提供了新的年代学证据。  相似文献   

11.
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.  相似文献   

12.
Robert L. Linnen   《Lithos》2005,80(1-4):267-280
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.  相似文献   

13.
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   

14.
《地学前缘(英文版)》2014,(3):I0001-I0003
正1 AIM AND SCOPE GEOSCIENCE FRONTIERS(GSF) is a bi-monthly international journal that publishes in English high quality original research articles and timely reviews in interdisciplinary fields of Earth and Planetary Sciences.GSF aims to bridge innovative,provocative and challenging concepts and models related to various fields of research including petrology and geochemistry in understanding lithospheric architecture  相似文献   

15.
正1 Introduction In the present paper,MgCl2·6H2O,FeCl3·6H2O,and CeCl3·6H2O were used as raw materials in the precipitationhydrothermal method to synthesize MgF eC e hydrotalcite.The effects of the Fe:Ce molar ratio on the composition,crystal structure,and thermal stability of hydrotalcite are examined.Energy-dispersive X-ray spectroscopy(EDS),X-  相似文献   

16.
正20141430 Chen Ji(Key Laboratory of Petroleum Resources,Chinese Academy of Sciences,Lanzhou 730000,China);Shi Ji’an Sedimentary Facies and Models for the Palaeogene-Neogene Deposits on the Northern Margin of the Qaidam Basin,Qinghai Province(Sedimentary Geology and Tethyan Geology,ISSN1009-3850,CN51-1593/P,33(3),2013,p.16-26,14 illus.,16 refs.)  相似文献   

17.
SEISMIC GEOLOGY     
正20141967An Zhanghui(Lanzhou Base of Institute of Earthquake Prediction,CEA,Lanzhou 730000,China);Du Xuebin Study onthe Geo-Electric Field Variation of Sichuan Lushan MS7.0and Wenchuan MS8.0Earthquake(Chinese Journal of Geophysics,ISSN0001-5733,CN11-2074/P,56(11),  相似文献   

18.
GEOCHEMISTRY     
正20141357 Guo Tao(School of Mathematics and Science,Shijiazhuang University of Economics,Shijiazhuang 050031,China);Hu Jiawen Assessment on the New Pressure-Volume-Temperature(PVT) Data of Supercritical Water(Geological Journal of China Universities,ISSN1006-7493,CN32-1440/P,19(3),2013,p.447-455,9 illus.,3 tables,32 refs.)Key words:supercritical fluids  相似文献   

19.
正20141074Bao Xijie(Research Institute of Exploration and Development,Daqing Oilfield Company,PetroChina,Daqing 163712,China)Gather Optimal Processing and Application Effect of Prestack AVA Instantaneous Inversion  相似文献   

20.
正China is lack of bromine and potassium seriously.Oilfield brines is the headline goal of bromine and potassium resources exploration.Applicants grab 24oilfield brines samples from various wells of Ordovician  相似文献   

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