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南岭地区各时代的花岗岩类,就其时空分布和共生关系来说,大概有四个较为明显的岩石组合: (1)以黑云母花岗岩为主的岩石组合。 (2)斜长花岗岩-花岗闪长岩组合。 (3)花岗斑岩-石英斑岩组合。 (4)以晶洞钾长花岗岩为主的岩石组合。本文要讨论的问题,就是这四个岩石组合是否代表四个成因系列。 相似文献
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计算花岗岩类斜长石牌号的一种方法黄茂新用岩石化学方法,通过校正花岗岩类共生矿物中的有关阳离子原子数,得到进入斜长石中的钠原子数和钙原子数,从而计算出花岗岩类的斜长石牌号,计算结果与实测结果比较,效果良好。本法可用于花岗岩侵入体,亦可用于花岗岩类相当的火山岩与次火山岩,但岩石成分必须属铝过饱和或正常系列;计算 相似文献
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甘肃北山柳园地区花岗岩类的年代学、地球化学特征及构造意义 总被引：8，自引：10，他引：8
北山柳园地区分布大量的花岗岩类岩石,岩石类型有花岗闪长岩、二长花岗岩、钾长花岗岩和斑状花岗岩。锆石SHRIMP U—Pb 定年分析结果为:花岗闪长岩的侵位年代为423±8Ma 辉铜山以东(HT-)钾长花岗岩和二长花岗岩的侵位分别为436±9Ma 和397±7Ma。该区花岗质岩石都具有大离子亲石元素和轻稀土元素相对富集,K、Ni、Ta、P 和 Ti 负异常的特征,属于准铝质到过铝质的高 K 花岗岩。花岗闪长岩无 Sr 和 Eu负异常的特征,ε_(Nd)(t)=-2.5～-0.8,其岩浆源于岩石圈地幔或是软流圈与岩石圈地幔相混合的岩浆熔融,并受到了含有火山弧组分的年轻地壳的混染。钾长花岗岩和二长花岗岩具有 Sr 和 Eu 负异常的特征,ε_(Nd)(t)值分别为 1.4、-4.0～-2.0和-2.7～-0.3。HT-钾长花岗岩岩浆主要源于由于岩石圈地幔岩浆作用而导致上覆年轻地壳物质的部分熔融;花牛山附近(HN-)钾长花岗岩岩浆主要源于软流圈地幔部分熔融,可能受到了部分年轻地壳物质的混染;二长花岗岩岩浆主要源于年轻地壳的部分熔融。柳园地区4类花岗岩类岩石都是后碰撞构造背景下的岩浆产物,岩浆形成可能与俯冲板片断离有关。 相似文献
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柴达木盆地北缘古生代超高压带中花岗质岩浆作用 总被引：38，自引：0，他引：38
吴才来 杨经绥 许志琴 Joseph L.WOODEN Trevor IRELAND 李海兵 史仁灯 孟繁聪 陈松永 Harold PERSING Anders MEIBOM 《地质学报》2004,78(5):658-674
祁连南缘古生代超高压变质带 (榴辉岩年龄为 4 6 6～ 4 95 Ma)上一套中高级变质岩系 (达肯大坂片麻岩 )中存在三类花岗岩组合 : 类 :石英二长闪长岩 -花岗闪长岩 -二长花岗岩 , 类 :二长花岗岩 -二云母花岗岩-含白云母花岗岩 -正长花岗岩 , 类 :花岗闪长岩 -二长花岗岩 -黑云母花岗岩。 类岩石组合中的二长花岗岩锆石SHRIMP年龄为 4 73Ma, 类岩石组合中的正长花岗岩锆石 SHRIMP年龄为 4 4 6 Ma, 类岩石组合中的二长花岗岩锆石 SHRIMP年龄为 397Ma。从三类花岗岩组合的组成矿物来看 , 类和 类的矿物组合主要为斜长石、角闪石、石英、碱性长石、黑云母 , 类的矿物组合为钾长石、石英、白云母、黑云母、斜长石 ;从岩石地球化学特征上看 , 类和 类花岗岩为 型花岗岩 ,岩石的 Si O2 =6 1%～ 6 9% ,Na2 O/ K2 O>1,ANK<1,δEu=0 .7～ 1.0 ; 类花岗岩为 S型花岗岩 ,岩石的 Si O2 =70 %～ 76 % ,Na2 O/ K2 O<1,ANK>1,δEu=0 .1～ 0 .3;从构造环境上看 , 类花岗岩形成于岛弧环境或活动大陆边缘 , 类花岗岩形成于同碰撞 , 类花岗岩形成于碰撞后。结合区域地质特征 ,我们认为 ,早奥陶世 ,南祁连洋板块向北俯冲于祁连陆块之下 ,规模不大的南祁连洋很快闭合 ,但俯冲下去的大洋板块仍拖动柴达木陆块继续俯冲 ,俯冲 相似文献
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华北克拉通北缘中生代高锶花岗岩类地球化学与源区性质 总被引：63，自引：19，他引：44
华北克拉通北缘广泛分布中生代高锶花岗岩类,其岩石类型主要包括石英闪长岩、花岗闪长岩、石英二长岩和二长花岗岩,以普遍发育条纹长石为主要岩相学特征.高锶花岗岩总体上具有富钠、高钾和高铝的岩石化学特征.根据16个代表性岩体共61个样品的分析结果,本区的高锶花岗岩可被明显地划分为低硅岩石组(SiO2 = 53%～60%)和高硅岩石组(SiO2 = 65%～73%),缺乏SiO2 = 60%～65% 的岩石,因而具有"双峰"分布特点.绝大多数高硅岩石属于高钾钙碱系列,而低硅岩石既有属于高钾钙碱和普通钙碱系列的,也有属于岛弧拉斑玄武岩系列和钾玄岩系列的.其微量元素以高锶、亏损重稀土及不发育明显富铕异常为重要特征,并以此明显区别于非高锶花岗岩.根据高锶花岗岩的岩石地球化学特征,并将它们与近年来许多天然岩石在不同温压条件下脱水熔融实验所获熔体进行了广泛对比,认为该区高锶花岗岩类的低硅岩石的源岩应为玄武质角闪岩类,而高硅岩石的源岩则为变中酸性火成岩类.源区部分熔融应该是在高温(T > 850～900 ℃)和高压(P ≥ 1.5 GPa)条件下进行的.熔体从源区抽取后的岩浆过程中没有经历明显的长石矿物的分离结晶,因而高锶花岗岩类可能代表起源于加厚地壳底部或壳幔过渡带的较为原始的岩浆.与高锶花岗岩浆相对应的源区残留固相应为石榴子石+单斜辉石±斜方辉石±角闪石±石英,属于麻粒岩相或榴辉岩相矿物组合.这些残留固相或滞留源区可能成为新的下地壳底部岩石,或因密度倒转而拆沉进入上地幔. 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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本文基于汇集的39个锆石SHRIMP和LA-ICP-MSU-Pb同位素年龄,186件岩石化学样品,并参考前人已有划分方案,提出鲁西地区早前寒武纪花岗岩类初步年代格架:(1)新太古代早中期(2741～2612Ma);(2)新太古代晚期(2563～2500Ma);(3)古元古代早期(2494～2435Ma)。探讨与之相对应的岩石组合和演化趋势:(1)英云闪长岩(T1)-奥长花岗岩(T2)-花岗闪长岩(G1),具奥长花岗岩演化趋势;(2)英云闪长岩(T1)-奥长花岗岩(T2)-花岗闪长岩(G1)-花岗岩(G2)-石英二长岩(QM),同时兼具奥长花岗岩演化趋势和钙碱性演化趋势;(3)花岗岩(G2)-石英二长岩(QM),具钙碱性演化趋势。基于SiO2-MgO和SiO2-FeO*/MgO关系,提出T1T2G1绝大部分具镁安山质岩石系列(MA)的性质,指示它们形成于洋俯冲环境,并结合岩石组合的类型,论证了第一、二、三期花岗岩类分别形成于岛弧、大陆边缘弧和大陆碰撞环境。进而认为,第一、二、三期花岗岩类代表了新生的初始不成熟陆壳,过渡性的半成熟陆壳和成熟的陆壳。这样,鲁西地区从新太古代早中期,经新太古代晚期,至古元古代早期的花岗岩类,记录了鲁西地区大陆地壳形成的完整的地质演化过程。 相似文献
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华南腹地白垩纪A型花岗岩类或碱性侵入岩年代学及其对华南晚中生代构造演化的制约 总被引：33，自引：14，他引：33
华南腹地存在多个白垩纪的A型花岗岩类或碱性侵入岩,如安徽花山霓辉石钠闪石花岗岩、福建大沅村霓辉石钠铁闪石花岗岩、广东恶鸡脑霞石方钠石正长岩以及浙江大和山辉石石英正长斑岩、苏村晶洞钾长花岗岩。锆石SHRIMP和矿物的40Ar-39Ar年代学研究表明,这些岩石主要形成于137-86Ma。以本文的年代学研究为基础,并结合前人大量研究成果, 将华南晚中生代的A型花岗岩类或碱性侵入岩大致分成三期:(1)侏罗纪(184-152Ma)A型花岗岩类或碱性侵入岩,主要沿“十-杭裂谷带”南段分布,在赣南也有分布,可能与古太平洋板块低速斜向俯冲或平移所导致的走滑伸展或与不受古太平洋板块运动影响的岩石圈伸展有关;(2)早白垩世(139-123Ma)A型花岗岩类或碱性侵入岩,分布于政和-大埔断裂带以西,可能与古太平洋板块快速斜向俯冲所导致的弧后伸展或岩石圈减薄有关;(3)晚白垩世(101-86Ma)A型花岗岩类或碱性侵入岩,主要沿闽浙沿海地区分布,同时在华南腹地也有零星分布,可能与大陆边缘弧的塌陷(collapse)或俯冲洋壳反转(roll- back)后的岩石圈伸展有关。 相似文献
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Guboglo M. N. 《GeoJournal》1980,4(1):53-58
International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen. 相似文献
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Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth
B. P. Kondratyev 《Astronomy Reports》2017,61(8):709-714
It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T 3 = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″. 相似文献
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Chronological analyses of correlations between certain global repeating events (mass extinctions of marine organisms, meteorite impacts, and flashes in the frequency of geomagnetic reversals) during the Phanerozoic Eon and the motion of the solar system in the Galaxy are presented for five rotationally symmetrical models for the regular Galactic gravitational field. Thirteen of sixteen mass-extinction events can be described by a repetition interval of 183±3 million years. This is in agreement with the anomalistic period (interval between two subsequent passages of the Sun through the apocenter of its Galactic orbit) in the model of Allen and Martos. The positions of the minima and maxima in Gaussian functions approximating the frequency distribution for geomagnetic reversals also agree with the times of passage of the Sun through the apocenter and pericenter, respectively, of its Galactic orbit in this model. The maximum in the distribution of the deviations of the dates of mass extinctions from the nearest dates of impacts of large, crater-forming bodies is close to zero, providing evidence that many such events are correlated. As a rule, extinctions follow impact events. The impacts of large bodies have occurred most often when the solar system passes through the Galactic plane, while mass extinctions occur more often at some distance from the Galactic plane (about 40 pc). As a rule, intervals of increases in the frequency of geomagnetic reversals coincide with dates of impacts of large bodies. At the same time, these intervals do not show a clear correlation with the dates of mass extinctions. The intensity of mass extinctions, like the energy released by impacts, is consistently higher in periods when the Sun is moving from the apocenter toward the pericenter of its orbit, than when it is moving from the pericenter toward the apocenter. Thus, there is evidence for a variety of relationships between repeating global events in the Phanerozoic and the motion of the Sun in the Galaxy. Long-period variations in the frequency of geomagnetic reversals are correlated with the orbital motion of the Sun, and increases in the frequency of geomagnetic reversals are correlated with impacts. Mass extinctions are correlated with the impacts of large bodies, whose motions may have been perturbed by clouds of interstellar material concentrated toward the Galactic plane and by the shock front associated with the Perseus spiral arm, through which the solar system passes. The velocity of the Sun relative to the spiral pattern is estimated. 相似文献
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位于华北和扬子两板块碰撞带中的苏鲁榴辉岩形成的温压条件不但是超高压，而且是高温。榴辉岩的PTt轨迹表明其为陆-陆磁撞俯冲带的产物。榴辉岩的区域性围岩花岗质片麻岩为新元古代同碰撞期花岗岩，榴辉岩及其他直接围岩皆呈包体存在于其中，并见新元古代花岗岩呈脉状侵入榴辉岩包体中。区域性围岩新元古代花岗岩的锆石中发现有柯石英、绿辉石等包裹体，表明新元古代花岗岩的组成物质也经受过超高压变质作用，且榴辉岩与围岩新元古代花岗岩的锆石U-Pb体系同位素年龄基本相同。但新元古代花岗岩所记录的变质作用和变形作用期次（或阶段）却少于榴辉岩。椐上述可得如下推断：超高压榴辉岩与新元古代花岗岩岩浆是同时在碰撞带底部（俯冲板块前部）形成的；榴辉岩的第一折返阶段是由新元古代花岗岩岩浆携带上升的，其第二折返阶段是和新元古代花岗岩一起由逆冲及区域性隆起而上升，遭受剥蚀。 相似文献
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某高速公路下伏煤矿采空区稳定性分析 总被引：10，自引：0，他引：10
在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。 相似文献
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摩擦桩基桩土间极限摩阻力取值问题探讨 总被引：1，自引：0，他引：1
通过对广珠东线高速公路横沥大桥的试桩及土体的工程地质条件分析,总结出影响摩擦桩基桩土间极限摩阻力取值的一般问题以及解决问题的方法和措施。 相似文献
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The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads 总被引：3，自引：1，他引：2
Clemente Irigaray Francisco Lamas Rachid El Hamdouni Tomás Fernández José Chacón 《Natural Hazards》2000,21(1):65-81
In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning. 相似文献
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The structure of the eastern Pyrenees consists mainly of south-directed thrusts involving basement and cover rocks. An antiformal stack developed by the piling up of basement thrust sheets which outcrop in the Axial zone. These structures account for a thin-skinned thrust model rather than a vertical fault model in which the Axial zone would be essentially autochthonous, and the North-Pyrenean fault the axial plane of a fan thrust system. New data from the Eastern Pyrenees and the thin-skinned model suggest that(1) the structure east of the Pedraforca nappe is similar to that of the Central Pyrenees; (2) the cover rocks of the South-Pyrenean units and of the Axial zone-after restoration—built up a northwards-thickening prism consistent with the existence of a unique Pyrenean sedimentary basin during Mesozoic time; (3) the Axial zone is only a complex antiformal stack developed as a part of South-Pyrenean system related to the Paleogene thrusting-tectonics. The Axial zone palaeogeographic area had no special meaning during Mesozoic time. 相似文献