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1.
西昆仑加里东期花岗岩带的地质特征 总被引：10，自引：0，他引：10
西昆仑地区加里东期花岗岩极为发育,主要沿库地北构造带南侧成带分布,岩体数量多、规模大,不同测试方法获同位素年龄主要为４００￣４８０Ｍａ;岩石组合类型大致可分为石英闪长岩－花岗闪长岩－二长花岗岩组合－钾长花岗岩－二长花岗岩组合和石英闪长岩－花岗闪长岩－斜长花岗岩组合;岩石化学表明该区花岗岩主要为钙碱性系列;构造环境判别岩石为同造山和造山期前岩浆活动产物。结合区域地质资料及与之相伴生蛇绿岩带的地质特征 相似文献
2.
新疆阿拉套山花岗岩带的主要特征及形成构造环境 总被引：2，自引：0，他引：2
阿拉套山花岗岩带产出于巩乃斯板块东北缘，岩带的岩石组合、化学成分、同位素组成表现出由东北向西南的系统变化，随离俯冲带距离的增大，古老地壳物质的贡献愈显著。构造环境判别表明早期花岗闪长岩－二长花岗岩组合产出于岩浆弧环境，与消减作用直接有关，晚期二长花岗岩－碱长花岗岩组合为造山后花岗岩，产出于张性环境，其形成标志着造山作用的结束。 相似文献
3.
本文对华北克拉通北缘中段赤峰撰山子矿区二长闪长岩、花岗(斑)岩等进行了岩相学、地球化学、锆石U-Pb定年以及Hf同位素研究,以期对古亚洲洋演化形成制约。锆石U-Pb定年显示,二长闪长岩和花岗岩形成于早石炭世(341.0±2.2Ma、324.1±4.3Ma),花岗斑岩形成于晚二叠世(252.8±3.2Ma、252.0±1.5Ma)。岩石地球化学及Hf同位素表明,二长闪长岩为高钾钙碱性I型花岗岩,形成于火山弧环境,其源区可能是俯冲板片脱水交代的地幔楔部分熔融产生玄武质岩浆上涌,导致新生地壳物质的部分熔融,并有部分玄武质岩浆加入形成的产物;花岗岩及花岗斑岩均为高钾钙碱性A型花岗岩,花岗岩形成于火山弧环境,花岗斑岩形成于造山后伸展环境,二者皆为新生地壳部分熔融的产物。综合前人研究认为,早石炭世-晚二叠世,研究区经历了古亚洲洋俯冲、弧-陆碰撞以及造山后伸展等阶段。 相似文献
4.
川西义敦岛弧碰撞造山带北段雀儿山复式花岗杂岩体的年代学和全岩地球化学研究表明,雀儿山杂岩体主要由花岗闪长岩、二长花岗岩和正长花岗岩组成。锆石LA--ICP--MS U--Pb测年结果显示,该岩体中的花岗闪长岩形成时代为晚三叠世(224±3 Ma),二长花岗岩则形成于早白垩世(102±1 Ma)。地球化学数据表明,晚三叠世花岗闪长岩为火山弧岩石序列,形成环境为碰撞前俯冲环境;早白垩世二长花岗岩和正长花岗岩为后碰撞岩石序列,形成于造山期后板内或陆内环境。结合区域地质资料,认为雀儿山杂岩体为印支期—燕山期义敦岛弧碰撞造山带经历俯冲--碰撞--隆升过程中的产物。 相似文献
5.
北祁连西段小柳沟矿区花岗质岩石锆石U-Pb年代学、地球化学及成因研究 总被引：8，自引：2，他引：6
甘肃小柳沟钨钼(铜)矿是一个与花岗岩类有关的斑岩-矽卡岩-石英脉型矿床,小柳沟矿区内花岗质岩石类型主要为二长花岗岩和花岗闪长岩。本文对该岩体进行年代学、地球化学研究以约束其形成时代和岩石成因。LA-ICP-MS锆石UPb测年分别获得二长花岗岩与花岗闪长岩谐和年龄为454.0±2.0Ma和417.7±1.7Ma,属于加里东期岩浆活动的产物,并经历了海西期和燕山期岩浆热事件的改造。地球化学数据显示,小柳沟花岗质岩石具有高硅、富碱的特征,属于过铝质高钾钙碱性系列,富集Rb、Th、U、K、Pb,亏损Ba、Sr、Ti、P,具有明显Eu负异常,尤其是二长花岗岩显示强烈的铕负异常(δEu为0.08～0.19),属于高分异I型花岗岩。锆石Hf同位素分析结果显示,二长花岗岩εHf(t)为-4.45～4.04,t DM2=1176～1714Ma,花岗闪长岩εHf(t)为-4.18～4.43,t DM2=1124～1670Ma,二者可能是由壳幔混合作用形成,其壳源源区很可能来源于古元古代-中元古代古老地壳岩石,花岗闪长岩的源区相对较深,北大河岩群与朱龙关群可能是小柳沟钨矿的初始矿源层。综合研究表明,小柳沟钨钼矿床与二长花岗岩在时间、空间及成因上有密切关系。结合区域构造演化,认为小柳沟二长花岗岩应形成于俯冲背景下的活动大陆边缘环境,花岗闪长岩形成于碰撞造山环境。 相似文献
6.
在编制1∶50万山东省大地构造相图基础上,通过对大地构造相研究显示：胶东微地块是经多期增生和碰撞而形成的,其漫长的板块构造演化明显具有阶段性。侏罗纪是该区板块构造演化史上的一个重要转换期,构造演化由原来的南、北分异转变为东、西分异,胶东地区NE向新生构造起了主要作用。胶东地区中生代有2次重要的碰撞造山事件,印支造山作用主要表现为扬子板块向华北板块俯冲,形成苏鲁高压-超高压变质带及同造山花岗岩及后造山高碱正长岩;燕山造山作用的大陆动力学环境起源于中亚-特提斯构造域向滨太平洋构造域转化和太平洋板块的俯冲,在胶东地区表现为3次造山和3次伸展。晚侏罗世造山早期玲珑片麻状花岗岩组合是区域构造挤压导致地壳增厚引起地壳重熔的产物,代表了大陆弧花岗岩特征;早白垩世造山中期郭家岭花岗闪长岩-花岗岩组合代表了造山期大陆弧花岗岩的特点;造山晚期伟德山闪长岩-花岗闪长岩-花岗岩组合表现为大陆弧花岗岩,后造山A型崂山晶洞过碱性碱长花岗岩-正长花岗岩组合为大陆造陆隆升花岗岩与后造山花岗岩,代表燕山构造的结束。胶东地区构造-岩浆事件和金矿成矿作用受控于特提斯、古亚洲洋和太平洋三大构造域的相互作用,金矿形成的动力学背景是中生代构造体制转折和岩石圈减薄,起因与太平洋板块向华北板块的俯冲机制有关。 相似文献
7.
大巴－建设地区太古宙花岗质岩石由英云闪长岩、奥长花岗岩、花岗闪长岩组成，属ＴＴＧ岩系。地质、岩石学及地质化学特征表明，它们是古深成侵入体，变质程度属绿片岩相。同位素年龄为２４４３Ｍａ。岩浆来源于陆壳的部分熔融。 相似文献
8.
通过对前人就郭家岭花岗岩构造地质学、岩石化学、同位素年代学等地质信息资料的分析、研究,认为胶东地区郭家岭花岗闪长岩一花岗岩总体上归属于幔源岩浆与壳源岩浆混合后经分异作用而成的同熔深成型花岗岩类;主要形成于由洋壳俯冲引起的火山岛弧环境、大陆碰撞环境和弧后拉张性质的大陆边缘环境;其定位机制为：沿着NEE向挤压带从小面积到大面积频率式脉动或涌动热轻气球膨胀式定位;该岩石构造组合主体形成于早白垩世。从岩石构造组合的概念,将其定义为造山中期郭家岭弱片麻状花岗闪长岩～花岗岩组合。 相似文献
9.
天山中段(东经86°—89°),尤其是中天山和南天山地区,花岗质岩浆活动十分发育,岩体多,规模大,以岩基为主,岩株次之。岩石类型以花岗岩居多,闪长岩、石英闪长岩、花岗闪长岩次之。多年来,新疆地矿局区测队对本区的花岗岩做了许多工怍,划分出加里东晚期花岗岩,海西早期、中期和晚期花岗岩,其中以海西早期花岗岩最为发育,其它各期均不太发育,属加里东晚期的仅有几个规模不大的长条状岩体。我们在前人工作的基础上认为本区不但存在强烈的海西期花岗质岩浆活动,而且存在强烈的晋宁期和加里东期岩浆活动和变质作用。 相似文献
10.
冈底斯带桑巴区早白垩世后碰撞花岗岩类的确定及构造意义 总被引：14，自引：0，他引：14
桑巴区花岗岩体位于冈底斯带嘉黎断裂之北,呈近东西向分布于桑巴、建多等地。岩石类型主要有巨斑黑云母花岗岩、黑云母花岗岩及斑状花岗闪长岩。其中斑状花岗闪长岩(TW1530)的SHRIMP锆石U-Pb年龄为117.2±1.6Ma,黑云母花岗岩(TW1637)年龄为121.2±1.7Ma,表明桑巴区花岗岩体形成于早白垩世。桑巴区花岗岩类为高钾钙碱性岩,根据地球化学特征和微量元素构造判别图解,确定该时代的花岗岩具后碰撞花岗岩特征,形成于从挤压体制向拉张体制转变的构造环境。早白垩世后碰撞花岗岩的出现预示着班公湖怒江缝合带主造山作用的结束,冈底斯火山岩浆弧带至此进入造山后伸展构造环境,并一直持续至晚白垩世竟柱山组沉积之前。 相似文献
11.
Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
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.
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
13.
The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
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.
Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozac&#x;h Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
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
15.
正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level 相似文献
16.
正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7), 相似文献
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正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci- 相似文献
19.
正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli- 相似文献
20.
正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.) 相似文献