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1.
建平变质杂岩是辽宁西都太古代最下部地质单元,是华北地台北缘麻粒岩相带的重要组成部分。它由少量连续性很差的表壳岩及大量的TTG岩石和其他深成侵入体组成。采用单颗粒锆石Pb蒸发法对其中的TTG岩石及其他侵入岩进行了年龄测定。结果表明:本区TTG花岗质岩浆约于2521Ma开始活动,并于2500Ma左右达到高峰,形成了大量的TTG质侵入体(包括部分喷出岩);紧随其后,本区发生强烈的高级变质变形事件,此事件约于2483~2490Ma达到高峰,使得已形成的岩石变成麻粒岩、紫苏花岗岩及斜长紫苏花岗岩等;于2472Ma就位的与退变质作用有关的后构造花岗岩标志着本区高级变质变形事件的结束。据此,可以推测建平变质杂岩可能形成于陆块形成后不久即发生大陆碰撞和地壳加厚的晚太古活动大陆边缘的环境中。  相似文献   

2.
建平变岩杂岩是辽宁西部太古代最下部地质单元,是华北地台北缘麻粒岩相带的重要组成部分它由少量连续性很差的表壳岩及大量的TTG岩石和其他深成侵入体组成。采用单颗粒锆石Pb函数法对其中的TTG岩石及其他侵入岩进行了年龄测定。结果表明:本区TTG花岗质夺浆约2521Ma开始活动,并于2500Ma左右达到高峰,形成了大量的TTG质侵入体(包括部分喷出岩);紧随其后,本区发生强烈的高级变质变形事件,此事件约于  相似文献   

3.
浙江洋滨黄玉花岗斑岩的Nd、Sr、Pb同位素研究   总被引:1,自引:0,他引:1  
洋滨斑岩锡矿位于我国东南沿海中生代火山活动带中部.含矿岩石主要由青黄玉的钾长花岗斑岩与二长花岗斑岩及黄英斑岩组成.这些岩石具有高硅、强过铝质、富集不相容元素、弱的铈和强的铕负异常以及高的稀土总量等特征.采用最小二乘法计算的全岩Rb-Sr等时线年龄为101.7±2.1Ma,(87Sr/86Sr)i=0.7142±9.同时,它们具有低的εNd值(-8.4~-8.0),较高的207Pb/204Pb(15.588~15.666)以及较古老的二阶段Nd模式年龄(1597~1743)Ma.这些特征表明,洋滨花岗斑岩的母岩浆属于S型,它们可能是由本区未出露的中元古代变质沉积岩经部分熔融方式形成.初始岩浆经历了强烈的分离结晶,继之以流体岩浆/分离过程。  相似文献   

4.
大兴安岭海西期造山带的演化:来自花岗质岩石的证据   总被引:4,自引:0,他引:4  
大兴安岭海西期花岗质岩石的地质,岩石学和地球化学研究以及晚古代生代沉积建造和火山-沉积建造的分析结果表明,海西早期的花岗闪长岩-斜长花岗岩组合(375~350ma)主要分布于乌奴尔和多宝山地区,前者形成于弧后盆地的引张环境,后者形成火山弧环境,海西中期的花岗闪长岩-二长花岗岩组合(390~310Ma)主要分布于多宝山地区,形成于板块碰撞后的的中 升环境,海西晚期的二长花岗岩-正长花岗岩组合(290  相似文献   

5.
粤东中生代花岗质火山-侵入杂岩成因的Nd同位素制约   总被引:1,自引:0,他引:1  
运用Nd同位素及稀土元素Nd的含量关系对岩浆成因的制约,结合区域地质地球化学特征,确定粤东地区中生代花岗质火山-侵入杂岩的成因机制,不是幔源岩浆同化地壳物质并发生分离结晶作用以及壳幔两种来源岩浆的混合作用,而是地壳深熔作用,即古老地壳基底岩石的部分熔融作用。  相似文献   

6.
在温度为650~900℃、围压为1100ΜΡa和应变率为10-4~10-7s-1的条件下,对大陆下地壳组成中的一类重要岩石——长英质麻粒岩进行了流变实验。稳态流动力学参数符合幂函数流动律ε=Aexp(Qc/RT)Δσn,其中A=0.27MPa-3s-1,Qc=288kJ/mol,n=3.0。该文将其外推到大陆下地壳变形环境下,讨论了下地壳的强度特征  相似文献   

7.
依据早元古代深成岩体与云开群的侵入接触关系,云开群中存在的隐蔽不整合,同位素年龄资料和稀土元素特征,把云开群中下部地层解体出来,新建立旺沙群和钱排群两个岩石地层单位,并厘定其形成时代分别为2300~2500Ma和1700~2300M  相似文献   

8.
粤东地区中生代金属矿床的成矿机制   总被引:3,自引:0,他引:3  
在前人大量系统和深入的成矿地质背景和成矿地质地球化学研究的基础上,根据粤东地区锡、钨、铜、银、金多金属矿床(点)区域成矿作用特征,着重探讨了在中生代花岗质火山-侵入杂岩岩浆作用的背景下,成矿元素的富集过程及成矿物质的迁移、沉淀机制.研究认为,成矿物质的富集经历了地壳岩石的选择性部分熔融、花岗质岩浆分异、流体-熔体分馏和流体与流经岩石相互反应(水-岩作用)4个阶段.由于作为热源的岩浆熔体的存在及不同成因断裂裂隙构造的产生,富含成矿元素的岩浆热液流体上升,并与深循环的大气降水热液混合,形成热液对流体系.在长期的热液对流循环中,随着构造脉动和物理化学条件的改变,沉淀出不同阶段的矿石,并在不同的构造部位和围岩中形成不同类型的矿床.  相似文献   

9.
辽河盆地西部凹陷南区的火山岩主要分布于中生界和下第三系,岩石类型多种多样。在岩石取心和岩石薄片不多的情况下,为了对本区火山岩准确定名,了解本区火山岩的地球化学特征以及岩浆的结晶分异等岩浆作用的形成和演化,对本区12块火山岩的主元素分布(包括铬、钴、镍等微量元素分析)和7块火山岩的稀土元素进行了分析。本区中生界岩石类型主要为安山岩和碱流岩,而房身泡组主要是碱性玄武岩和玄武岩类,这表明在岩浆的演化过程中曾发生过橄榄石和辉石的结晶分异作用。本区火山岩应主要来自上地幔,而房身泡组源区相对较浅,可能有下地壳物质混人。  相似文献   

10.
浙江洋滨黄玉花岗斑石的Nd,Sr,Pb同位素研究   总被引:1,自引:0,他引:1  
洋滨斑岩锡矿位于我国东南沿海中生代火山活动带中部。含矿岩石主要由含黄玉的钾长花岗斑岩与二长花岗斑岩及黄英斑岩组成。这些岩石具有高硅,强过铝质,富集不相容元素,弱的铈和强的铕负异常以及高的稀土总量特征。采用最小二乘法计算的全岩Rb-Sr等时线年龄为101.7±2.1Ma,(^87Sr/^86Sr)i=0.7142±9。同时,它们具有低的εNd值(-8.4~-8.0),较高的^207Pb/^204Pb  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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