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1.
华南绍兴-恩平富碱侵入岩带的厘定及其动力学意义初探 总被引：18，自引：5，他引：18
根据野外地质及室内岩相学、矿物成分和岩石化学的研究，从华南腹地厘定了一条重要的中生代NE向富碱侵入岩带－绍兴－恩平富碱侵入岩带。该岩带全长约1400km，宽100－150km，不仅发育有狭义的碱性岩（方沸黑云橄榄黄长岩、白榴黄长煌斑岩、霞石正长岩、霓辉石正长岩、黑榴石正长岩和含霓石石英正长岩）和碱性花岗岩（钠闪石花岗岩、霓辉石钠闪石花岗岩），还发育有大量的正长岩类－二长岩类－碱长花岗岩或晶洞钾长花岗岩。这些富碱侵入岩主要形成于晚中生代。绍兴－恩平燕山期富碱侵入岩带的厘定将对研究华南中生代的动力学的背景与演化具有重要的意义。 相似文献
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《新疆地质》2016,(1)
西南天山巴什索贡岩体侵位于下二叠统巴立克立克组中。该岩体主要由辉长岩、石英正长岩及碱长花岗岩组成。从岩石化学等资料分析,辉长岩Si O2含量46.16%~53.89%,为基性岩类,石英正长岩及碱长花岗岩Si O2含量为60.92%~74.6%,属酸性岩类,三者铝饱和指数A/CNK1.1,岩石类型均为偏铝质花岗岩。采用等离子体质谱-激光探针法(LA-ICP-MS),在辉长岩中和石英正长岩中获得锆石U-Pb年龄值分别为(273.95±0.85)Ma、(268.9±1.0)Ma,时代为中二叠世,代表巴什索贡岩体的生成年龄。辉长岩、石英正长岩及碱长花岗岩为碱钙性系列岩石,发生在碰撞后的张驰阶段,该期岩体的构造环境为板内拉伸环境下产物,具有板内裂谷特征。 相似文献
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水泉沟杂岩体的地质学和岩石学研究 总被引：7，自引：0，他引：7
水泉沟岩体为岩浆成因，岩体的侵位深度２－３ｋｍ，侵位时代为印支期，划分为４种岩石组合１，水泉沟岩体是一个钾质－高钾质的钙碱性，弱碱性和碱性岩石共存的杂岩体。岩石化学成分变异图解证明岩浆存在两种演化趋势，一是酸性演化趋势；辉石闪长岩－角闪二长岩－石英碱长正长岩－碱长花岗岩；二是碱性演化趋势；正长岩－霓辉正长岩－碱长正长岩。 相似文献
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后石湖山杂岩体是与垮塌破火山口有关的碱性环状杂岩体, 主要由呈环形分布的碱性火山岩、环状岩墙(斑状石英正长岩)、嵌套的中心复式岩株(晶洞碱长花岗岩和斑状碱长花岗岩)和锥状岩席(石英正长斑岩和花岗斑岩)组成.LA-ICPMS锆石U-Pb年代学分析表明, 斑状石英正长岩环状岩墙、石英正长斑岩和花岗斑岩锥状岩席的侵位年龄分别为119±3Ma、121±2Ma和121±2Ma.该环状杂岩体火山岩与侵入岩的形成年龄相近, 体现了它作为火山-侵入杂岩体的特征.斑状石英正长岩富碱(Na2O+K2O=10.0%~10.5%), K2O含量较高(5.21%~5.42%), 具正的Eu异常(Eu/Eu*=1.05~1.40).碱长花岗岩和斑岩均具有富碱、高FeOtot/MgO、Ga/Al、Zr、Nb和REE值(Eu除外), 以及低Al2O3、CaO、MgO、Ba、Sr和Eu含量的特征, 都属于A型花岗岩质岩石.其中斑岩为铝质A型花岗岩, 具有高的初始岩浆温度(880~901℃).所有A型花岗质岩石均具有较富集的Nd同位素组成, εNd(t)值变化于-13.9~-12.2之间.斑状石英正长岩是下地壳中-基性麻粒岩和片麻岩部分熔融产生的熔体与幔源玄武质岩浆混合, 后又发生单斜辉石分离结晶的产物; 碱长花岗岩源于上地壳长英质岩石部分熔融产生的熔体与幔源玄武质岩浆混合, 随后经历长石的分离结晶作用而成; 斑岩是受幔源岩浆底侵加热的上地壳长英质岩石的部分熔融产生的熔体, 并经历了长石的分离结晶作用而产生.该环状杂岩体的形成过程可以概括为: (1)火山爆炸性喷发形成大量的碱性火山熔岩和火山碎屑岩; (2)地下岩浆房空虚导致压力下降, 其顶板围岩失稳而沿火山口周围近直立的环状断裂垮塌, 形成塌陷的破火山口.与此同时, 下覆岩浆房的岩浆被动挤入环状断裂而形成斑状石英正长岩环状岩墙; (3)浅部地壳的长英质岩浆房过压, 促使其高温过碱质A型花岗质岩浆上升侵位形成了中心的斑状碱长花岗岩岩株, 这些岩浆的上涌导致上覆围岩产生倾角中-陡的、内倾的锥状裂隙, 为石英正长斑岩锥状岩席侵位提供了空间; (4)浅部岩浆房复活, 高温过碱质A型花岗质岩浆再度上升侵位形成被嵌套的晶洞碱长花岗岩岩株.同样, 这种岩浆的再度上侵导致上覆围岩产生了倾角较陡而内倾的锥状裂隙, 为花岗斑岩锥状岩席提供了侵位空间.后石湖山碱性环状杂岩体的形成是华北东部早白垩世与克拉通破坏相关的伸展构造体制下的产物, 这种构造体制可能与古太平洋板块的俯冲作用有关. 相似文献
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东秦岭北部富碱侵入岩岩石化学与分布特征 总被引：5，自引：1，他引：5
在东秦岭北部，富碱侵入岩的侵位与空间分布受同一个区域构造带（华并陆块南缘）控制，构成一个区域性的富碱岩浆岩带。根据岩石学和岩石化学研究，岩石类型主要分为三大类：（1）碱性岩类，即含有似长石或碱性暗色矿物的正长岩类；（2）碱性花岗岩类，包括钠铁闪石花岗岩及孪生的钾长花岗岩类；（3）石英正长岩类，包括碱性长石为主的石英正长岩、英碱正长岩和花岗正长（斑）岩类。根据富碱岩浆岩带的岩石化学特征，自北而南可以划分为三个亚带：北部碱性岩亚带，以SiO2饱和而l2O3不饱和出现碱性暗色矿物为特征；中部碱性花岗岩亚带，以SiO2强饱和而Al2O3不饱和出现碱性暗色矿物和大量石英为特征；南部石英正长岩亚带，以SiO2和Al2O3都饱和但CaO强烈亏损，缺乏Ca质斜长石，出现碱性长石占长石总量的绝对优势（一般＞95％）为特征。三个亚带富碱岩浆在化学成分方面虽有差异，但共同具有富碱高钾钙征，ALK＝10－15，K2O含量范围5％－15％，K2O／Na2O＝1．26－8．30。 相似文献
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大别山金鸡寨花岗岩体岩石化学特征及侵位机制初步探讨 总被引：2，自引：0，他引：2
】大别山金鸡寨花岗岩体位于大别山碰撞造山带东端,紧邻郯庐断裂,是由碱长石英正长岩和碱长花岗岩组成。这两种岩石的组成矿物均为碱性长石、石英、斜长石、角闪石、黑云母、磁铁矿及副矿物榍石、磷灰石,但矿物含量不同。它们的岩石化学特征也不相同：（１）碱长石英正长岩中常量元素的平均含量（ｗｔ％）ＳｉＯ２为６７．１１％,Ａｌ２Ｏ３为１７％,Ｎａ２Ｏ＋Ｋ２Ｏ为１０．９７％,其中Ｋ２Ｏ＞Ｎａ２Ｏ,微量、稀土元素均较富集,但高场强元素、轻稀土含量及ＬＲＥＥ／ＨＲＥＥ均大于碱长花岗岩中的相应数值。（２）碱长花岗岩中常量元素的平均含量（ｗｔ％）ＳｉＯ２为７５．１３％,Ａｌ２Ｏ３为１３％,Ｎａ２Ｏ＋Ｋ２Ｏ为８．２３％,其中Ｋ２Ｏ＞Ｎａ２Ｏ,微量、稀土元素含量较高,但大离子亲石元素、重稀土元素含量则大于碱长石英正长岩中的含量。根据野外调查、岩石学特征及常量、微量、稀土元素研究表明,这两种岩石是同一岩浆不同演化阶段的产物,是于造山后形成的Ａ型花岗岩,其形成经历了部分熔融和结晶分异两个阶段,源岩可能来自于北大别变质杂岩。金鸡寨岩体的侵位是以“半汽球”膨胀机制进行的,并与龙井关断裂密切相关。 相似文献
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水泉沟岩体为岩浆成因,岩体的侵位深度2~3km,侵位时代为印支期,划分为4种岩石组合.水泉沟岩体是一个钾质-高钾质的钙碱性、弱碱性和碱性岩石共存的杂岩体.岩石化学成分变异图解证明岩浆存在两种演化趋势,一是酸性演化趋势:辉石闪长岩→角闪二长岩(包括二长岩)→石英碱长正长岩→碱长花岗岩;二是碱性演化趋势:正长岩→霓辉正长岩→碱长正长岩.同时也探讨了这两种演化趋势的内在机理. 相似文献
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安徽两条A型花岗岩带 总被引：23，自引：9，他引：23
安徽长江两岸平行对称分布有两条Ａ型花岗岩带。江北为大龙山－城山－黄梅尖岩带；江南为花园巩－茅坦－浮山岩带。它们均由正长岩、石英正长岩和碱长花岗岩组成，形成年龄约１２８Ｍａ．这些岩石富碱贫水，全碱含量高达９％～１２％，而Ｈ２Ｏ＋只有约０．５％，富含高场强元素，Ｇａ×１０４／Ａｌ比值也高，花岗岩高达２．７～３．８。其形成环境为古裂谷拉张环境。两个岩带的花岗岩是正长岩浆通过ＡＦＣ（同化混染－分离结晶联合作用）机制演化形成，而正长岩浆则是碱性玄武岩浆通过以分离结晶为主的ＡＦＣ机制形成． 相似文献
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华北陆块南缘富碱侵入岩岩石组合及时空分布 总被引：8，自引：0，他引：8
华北陆块南缘出露的富碱侵入岩集中分布于卢氏－确山一。岩石类型主要分为三大类：（１）碱性岩类，即含有似长石或碱性暗色矿物的正长岩类；（２）碱性花岗岩类，包括钠铁闪石花岗岩以及孪生的钾长花岗岩类；（３）石英正长岩类；包括碱性长石来主的石英正长岩，英碱正长岩和花岗正长岩类。 相似文献
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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
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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
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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
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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
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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
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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