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1.
本文根据U-pb、Rb-Sr、40Ar/39Ar法测年资料,探讨了川西白玉-稻城地区花岗岩类的东岩带、中岩带、西岩带的形成时代。东带以200Ma为主,中带以80Ma为主,西带以220Ma为主,各方法所获年龄数据基本上可对比。  相似文献   

2.
郯庐断裂带北段形成的年代学及其意义   总被引:27,自引:2,他引:27  
窦立荣  王瑜 《地质论评》1996,42(6):508-512
对郯庐断裂带北段内的依兰-伊通断裂带测定断民支岩的黑云母单矿物^40Ar/^39Ar坪年龄为100±2.3-95.7±2.74Ma,同时测定了带内的辉绿岩全岩Rb-Sr等时线年龄为100±5.9Ma,而辉绿岩中辉石单矿物的^40Ar/^39Ar坪年龄为105Ma。结合断裂切过下白垩统泉头组,表明左行走滑断裂形成于100Ma左右,即早白垩世末期。  相似文献   

3.
吉林夹皮沟金矿成矿时代的研究   总被引:31,自引:1,他引:31  
李俊建  程玉明 《地质学报》1996,70(4):335-341
吉林夹皮沟金矿是我国与太古宙绿岩带有关的典型脉型金矿之一。根据岩脉与矿脉的穿插关系及单颗粒水热锆石U-Pb同位素年龄和石英的K-Ar,^40Ar-^39Ar,Rb-Sr年龄测定,表明夹皮沟金矿的主成矿期为2469-2475Ma,并有1800-2000Ma和272-130Ma的矿化叠加现象,构成了夹皮沟乃至中国与绿岩带有关的脉型金矿“一老(晚太古代-早元古代)一新(中生代)”的成矿格架。  相似文献   

4.
龙泉关韧性剪切带的年代学研究   总被引:11,自引:0,他引:11       下载免费PDF全文
龙泉关韧性剪切带位于山西、河北两省分水岭以西的狭长地区内。本研究的考察路线为阜平县龙泉关乡至长城岭公路沿线,穿过了韧性剪切带。对龙泉关构造岩进行了石英包裹体测温和矿物对氧同位素温度计测温,该剪切带的形成温度大于460℃,大于黑云母的K-Ar封闭温度。超糜棱岩及两侧岩石中七个黑云母等矿物的Ar-Ar定年和全岩Rb-Sr定年表明,该剪切带形成于1952—1914Ma前后,在韧性剪切过程中Sr同位素有可能重新达到均一化。锆石的U-Pb年龄为2506Ma,它代表原岩的形成时代。  相似文献   

5.
我国一些碱性岩的同位素年代学研究   总被引:34,自引:3,他引:34  
周玲棣  赵振华 《地球化学》1996,25(2):164-171
对我国七个碱性岩体用一种或两种方法进行了年龄测定。Rb-Sr测定了岩石及微斜长石;40Ar-39Ar法测定了闪石、辉石、正长石及微斜长石;超基性碱性岩用Sm-Nd等时线法测定。各岩体年龄分别为:坪河462Ma,赛马244Ma,柏林川218Ma,紫金山153Ma,龙王庙150Ma,丫髻山127.5Ma,永胜31.7Ma,Isr为0.7044-0.7083。已获得的Sr、Nd同位素数据表明,碱性岩浆  相似文献   

6.
本文基于中国50个岩金矿床84组直接测年数据,提出中国金矿床具“一老(2500-1800Ma)一新(280-100Ma)”的成矿格架。区域分布上,前寒武纪形成的金矿床成矿年代为“西低东高”,而显生宙金矿为“西高东低”。中国金矿床最重要类型为绿岩带型金矿。测年方法上,应采用单颗粒含铀矿物U-Pb法,而40Ar/39Ar、K-Ar法和Rb-Sr等时线法仅适于测定显生宙形成的金矿床。  相似文献   

7.
季建清  钟大赉 《岩石学报》2000,16(2):227-232
中缅边界那邦变质基性岩出圳于东缅著名的Mogok带的东缘。那邦基性麻粒岩经历了早期麻粒岩相、晚期角闪岩相的两期变质作用的改造。早期变质作用的矿物石榴石和单斜辉石的^40Ar/^39Ar年龄谱图和等时线年龄均显示两组年龄:74 ̄76Ma和23 ̄24Ma。晚期变质作用矿物角闪石的K-Ar法得出23Ma,角闪石和斜长石的^40Ar/^39Ar年龄谱图和等时线年龄均显示23 ̄24Ma。晚期变质作用矿物角闪  相似文献   

8.
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   

9.
阿尔泰地区中、新生代岩浆活动的同位素年龄证据   总被引:25,自引:1,他引:25  
张前锋  李启新 《地球化学》1994,23(3):269-280
长期以来,对阿尔泰地区有无印支、燕山期岩浆活动一直存在争议。本研究得到以下年龄结果:将军山花岗岩(^40Ar/^39Ar坪年龄)220Ma、康布铁堡花岗岩(^40Ar/^39Ar高温视年龄)214Ma、尚可兰花岗岩(Rb-Sr全岩等时线年龄)176Ma、阿拉尔花岗岩(^40Ar/^39Ar坪年龄)131Ma。以上数据和与本区处在同一构造单元的前苏联矿区阿尔泰及山区阿尔泰12个浅色花岗岩锆石U-Pb  相似文献   

10.
京津地区铁岭组、景儿峪组海绿石~40Ar-~39Ar年龄   总被引:8,自引:0,他引:8  
利用海绿石40Ar-39Ar年龄校正公式,通过测量海绿石中的可膨胀层含量n以及中子活化过程中39Ar的丢失率,求出海绿石的年龄。经测定,京津地区铁岭组、景儿峪组海绿石中可膨胀层含量为5%~6%,中子活化中39Ar丢失率为17%~19%。由校正后的海绿石年龄推测出铁岭组年龄界限范围是1070±10Ma~1175±10Ma,景儿峪组为810±10Ma~900±10Ma。  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.
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   

13.
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   

14.
15.
Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ1 roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).  相似文献   

16.
正20141520 Bo Ying(Key Laboratory of Metallogeny and Mineral Assessment,MLR,Beijing 100037,China);Liu Chenglin Saline Spring Hydrochemical Characteristics and Indicators for Potassium Exploration in Southwestern and Northern Tarim Basin,Xinjiang(Acta Geoscientica Sinica,ISSN1006-3021,CN11-3474/P,34(5),2013,p.594-602,5 illus.,3 tables,28 refs.)  相似文献   

17.
正20141243Chen Ge(Hangzhou Research Institute of Petroleum Geology,PetroChina,Hangzhou 310023,China);Si Chunsong Study on Sedimentary Numerical Simulation Method of Fan Delta Sand Body(Journal of Geology,  相似文献   

18.
正20142599Chen Sanming(Guangxi Key Laboratory of Concealed Deposits Exploration,Guilin University of Technology,Guilin541004,China);He Yuzhou Block Model and Reserves Estimation of Panzhihua Iron Deposit Based on 3D Geological Modeling(Journal of Guilin University of Technology,ISSN1674-9057,CN45-1375/N,33(4),2013,p.610-615,9illus.,1table,15refs.)  相似文献   

19.
正20140594 Bai Daoyuan(Hunan Institute of Geology Survey,Changsha 410016,China);Zhong Xiang Faults in the Jingzhou Basin and Their Tectonic Settings(Geotectonica et Metallogenia,ISSN1001-1552,CN44-1595/P,37(2),2013,p.173-183,6illus.,59refs.)Key words:basin evolution,tectonic setting,South China In the Upper Paleozoic and Jurassic se-  相似文献   

20.
正20141912Cao Hui(State Key Laboratory for Continental Tectonics and Dynamics,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China)Gravitational Collapse and Folding during Orogenesis:A Comparative Study of FIA Trends and Fold Axial Plane Traces(Geology in China,ISSN1000-3657,CN11-1167/P,40(6),2013,p.1818-1828,9illus.,35refs.,with  相似文献   

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