新疆鄯善康古尔塔格蛇绿岩及其大地构造意义   总被引：4，自引：1，他引：4  

李文铅  夏斌吴国干  王核王冉 《岩石学报》2005,21(6):1617-1632

康古尔塔格蛇绿岩的岩石组合为变质橄榄岩-堆晶橄榄岩-辉长岩-斜长花岗岩-辉绿岩-玄武岩。方辉橄榄岩（蛇纹岩）、蛇纹石化辉石岩、蚀变辉长岩与特罗多斯蛇绿岩中同类型岩石类似，岩石总体低钾。变质橄榄岩MgO／（MgO＋TFeO）为0．834～0．866，TiO，（wt％）为0．02％，为SSZ型蛇绿岩的变质橄榄岩。玄武岩的构造环境判别显示其形成于边缘海盆。放射虫硅质岩的Al2O3／（Al2O3＋Fe2O3）值平均为0．047，MnO／TiO2比值平均为0．93，Ce具负异常，Ce／Ce^＊=0．548，Lan／Cen=1．661．表明放射虫硅质岩的形成环境与洋中脊有密切关系。该蛇绿岩位于塔里木板块和哈萨克斯坦-准噶尔板块的艾比湖-康古尔塔格缝合线上，为一套无序产出的古生代北天山洋在该区的古洋壳残片。  相似文献   

H-90B微机γ能谱比活度测量仪     

张彪  梁树红  齐宁  张兆山  吴慧山 《铀矿地质》2005,21(2):118-122

本介绍了H-90B微机γ能谱比活度测量仪的研制方案、仪器组成特点及主要技术指标；简述了仪器的工作原理，工作条件及测量方法；最后，介绍了其在现场检测建筑材料放射性比活度方面的应用情况。  相似文献   

新疆库鲁克塔格地区二叠纪脉岩群岩石地球化学特征，Nd、Sr、Pb同位素组成与岩石成因   总被引：12，自引：22，他引：12       下载免费PDF全文

姜常义姜寒冰  叶书锋夏明哲 逯东霞 《地质学报》2005,79(6):823-833

库鲁克塔格地区二叠纪脉岩群非常发育,主要岩石类型是辉绿岩,并有少量的斜闪煌斑岩、斜长玢岩和花岗斑岩。花岗斑岩属高钾钙碱性系列,具有A型花岗岩的稀土元素和微量元素地球化学特征;斜长玢岩的地球化学特征与花岗斑岩相似,二者都亏损U、Nb、Ta。斜闪煌斑岩的岩石化学组成属过碱性系列,显著富集轻稀土元素和大离子亲石元素。辉绿岩的岩石化学组成以钙碱性系列为主,稀土元素总量变化较大,Cs、Rb、Ba、Th元素丰度变化大,普遍亏损U、Nb、Ta。研究证明,辉绿岩脉的这些地球化学特征都与同化混染作用有关,大离子亲石元素丰度的变化还与热液蚀变有关。辉绿岩具有富集型Nd、Sr同位素组成,且变化范围大,是岩浆源区同化混染作用的结果。它们的铅同位素组成属低U(Th)/Pb值的正常铅,主要受混染物控制,并不代表源区特征。库鲁克塔格地区岩石圈地幔Nd、Sr、Pb同位素比塔里木板块西缘岩石圈地幔的富集程度更高,且变化范围大,反映了这两个地区岩石圈地幔的演化历史存在明显差异。  相似文献   

西藏松西地区辉绿玢岩岩石化学、地球化学特征及构造环境     

钟华明  王贵生  夏军  童劲松  鲁如魁 《安徽地质》2005,15(3):170-174

青藏高原南羌塘石炭纪-二叠世地层中侵入大量的辉绿玢岩岩墙群，其侵位时代为晚古生代。区域资料显示，这一时期该地区处于冈瓦纳大陆北部边缘。岩石化学、地球化学特征表明，辉绿玢岩与洋脊型、洋岛型及典型的大陆裂谷玄武岩都有明显区别，显示出大陆拉张带（或初始裂谷）的拉斑玄武岩特征。辉绿玢岩是冈瓦纳被动陆缘在晚古生代裂解的产物。  相似文献   

玛纳斯河山麓冲积扇演变遥感研究   总被引：4，自引：0，他引：4  

崔卫国  穆桂金  夏斌  马妮娜 《地理与地理信息科学》2006,22(3):39-42

基于地质过程,特别是沉积地质过程的理论和方法,通过对航空相片和遥感影像的解译,结合野外考察和地貌与沉积物分析,研究玛纳斯河山麓冲积扇的演变过程,并对其形成和演变原因进行探讨。晚第四纪以来,玛纳斯河山麓冲积扇从第二排山麓到下游冲积平原,可划分为四期规模较大和三期规模较小的冲积扇;玛纳斯河山麓冲积扇的形成演变受气候、构造或气候—构造耦合作用的共同影响,具有多成因性和多层次性。  相似文献   

大连港在建设东北亚国际航运中心中的作用   总被引：4，自引：0，他引：4  

张耀光  王宁  赵永宏 《地域研究与开发》2006,25(1):19-22

从国际航运中心发展来看，港口是航运中心建设的基础。我国提出：“充分利用东北地区现有港口条件和优势，把大连建设成东北亚重要的国际航运中心”，根据振兴东北老工业基地对大连港今后发展的要求，探讨了今后发展的指导思想、发展目标、基础设施和港口建设布局，并提出了对策和相应措施。  相似文献   

基于GIS的中国县级尺度交通便利性分析   总被引：3，自引：0，他引：3  

夏海斌  戴霄晔  王莹  王铮 《地域研究与开发》2006,25(3):120-124,F0002

文章以全国各县市的日航空、铁路班次数及高速公路、国道、省道、县乡道里程作为数据基础，给出了计算中国县级尺度交通便利性程度的模型，并运用相关模型与GIS技术得到中国县级尺度交通便利性的指标体系。从对中国现阶段交通便利性的空间布局进行综合分析发现中国交通便利性的分界线与“胡焕庸线”相一致；中国省内各县市的交通便利性差距较大；中国一些沿海经济区已经形成交通连绵区而内地的多数地区主要是以省会城市为聚集中心等。  相似文献   

基于芬兰经验的我国森林资源型城市的发展研究--以伊春市为例     

姜琳琳  张宁  臧淑英 《世界地理研究》2006,15(2):48-53,65

资源型城市的可持续发展问题一直是学术界的研究热点,但对于森林资源型城市的研究却不多见。本文概括介绍了芬兰的资源和经济发展情况,系统分析了芬兰这样一个以森林起家的经济发达国家的成功经验;并以伊春为例提出了森林资源型城市经济转型和可持续发展可资借鉴的对策和建议。  相似文献   

What Happened in the Trans-North China Orogen in the Period 2560-1850 Ma？   总被引：5，自引：0，他引：5  

Guochun ZHAO LIU Shuwen Min SUN LI Sanzhong Simon WILDE Xiaoping XIA Jian ZHANG Yanhong HE 《《地质学报》英文版》2006,80(6):790-806

The Trans-North China Orogen （TNCO） was a Paleoproterozic continent-continent collisional belt along which the Eastern and Western Blocks amalgamated to form a coherent North China Craton （NCC）. Recent geological, structural, geochemical and isotopic data show that the orogen was a continental margin or Japan-type arc along the western margin of the Eastern Block, which was separated from the Western Block by an old ocean, with eastward-directed subduction of the oceanic lithosphere beneath the western margin of the Eastern Block. At 2550-2520 Ma, the deep subduction caused partial melting of the medium-lower crust, producing copious granitoid magma that was intruded into the upper levels of the crust to form granitoid plutons in the low- to medium-grade granite-greeustone terranes. At 2530-2520 Ma, subduction of the oceanic lithosphere caused partial melting of the mantle wedge, which led to underplating of mafic magma in the lower crust and widespread mafic and minor felsic volcanism in the arc, forming part of the greenstone assemblages. Extension driven by widespread mafic to felsic volcanism led to the development of back-arc and/or intra-arc basins in the orogen. At 2520-2475 Ma, the subduction caused further partial melting of the lower crust to form large amounts of tonalitic-trondhjemitic-granodioritic （TTG） magmatism. At this time following further extension of back-arc basins, episodic granitoid magmatism occurred, resulting in the emplacement of 2360 Ma, -2250 Ma 2110-21760 Ma and -2050 Ma granites in the orogen. Contemporary volcano-sedimentary rocks developed in the back-arc or intra-are basins. At 2150-1920 Ma, the orogen underwent several extensional events, possibly due to subduction of an oceanic ridge, leading to emplacement of mafic dykes that were subsequently metamorphosed to amphibolites and medium- to high-pressure mafic granulites. At 1880-1820 Ma, the ocean between the Eastern and Western Blocks was completely consumed by subduction, and the dosing of the ocean led to the continent-arc-continent collision, which caused large-scale thrusting and isoclinal folds and transported some of the rocks into the lower crustal levels or upper mantle to form granulites or eclogites. Peak metamorphism was followed by exhumation/uplift, resulting in widespread development of asymmetric folds and symplectic textures in the rocks.  相似文献   

U-Pb Age and Hf Isotope Study of Detrital Zircons from the Wanzi Supracrustals： Constraints on the Tectonic Setting and Evolution of the Fuping Complex, Trans-North China Orogen   总被引：1，自引：0，他引：1  

Xiaoping XIA Min SUN Guochun ZHAO WU Fuyuan XU Ping Jian ZHANG Yanhong HE ZHANG Jiheng 《《地质学报》英文版》2006,80(6):844-863

Located in the middle segment of the Trans-North China Orogen, the Fuping Complex is considered as a critical area in understanding the evolution history of the North China Craton （NCC）. The complex is composed of various high-grade and multiply deformed rocks, including gray gneiss, basic granulite, amphibolite, fine-grained gneiss and marble, metamorphosed to upper amphibolite or granulite facies. It can be divided into four rock units： the Fuping TTG gneisses, Longquanguan augen gneisses, Wanzi supracrustals, and Nanying granitic gneisses. U-Pb age and Hf isotope compositions of about 200 detrital zircons from the Wanzi supracrustals of the Fuping Complex have been analyzed. The data on metamorphic zircon rims give ages of 1.82-1.84 Ga, corresponding to the final amalgamation event of the NCC, whereas the data for igneous zircon cores yield two age populations at -2.10 and -2.51 Ga, with some inherited ages scattering between 2.5 and 2.9 Ga. These results suggest that the Wanzi supracrustals were derived from the Fuping TTG gneisses （-2.5 Ga） and the Nanying granitic gneisses （2.0-2.1 Ga） and deposited between 2.10 and 1.84 Ga. All zircons with -2.51 Ga age have positive initial εHf values from ＋1.4 to ＋10.9, suggesting an important crustal growth event at -2.5 Ga through the addition of juvenile materials from the mantle. The Hf isotope data for the detrital zircons further imply that the 2.8 Ga rocks are important components in the lower crust, which is consistent with a suggestion from Nd isotope data for the Eastern Block. The zircons of 2.10 Ga population have initial εHf values of-4.9 to ＋6.1, interpreted as mixing of crustal re-melt with minor juvenile material contribution at 2.1 Ga. These results are distinct from that for the Western Block, supporting that the Fuping Complex was emplaced in a tectonic active environment at the western margin of the Eastern Block.  相似文献