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北秦岭老君山、秦岭梁环斑结构花岗岩岩浆混合的岩相学证据及其意义 总被引：1，自引：0，他引：1
老君山和秦岭梁岩体具有明显的岩浆混合特征.岩体中暗色包体发育,主要类型为细粒闪长质和二长质的岩浆包体,有的岩浆包体具有细粒边,有的和寄主岩石呈过渡关系.包体的矿物组合明显不平衡:出现石英-角闪石眼斑;暗色矿物中有石英包裹体;磷灰石呈针状.在包体、寄主岩石及其边界上广泛出现卵球状的碱性长石斑晶.这些混合特征表明:老君山和秦岭梁环斑结构花岗岩、环斑结构与岩浆混合关系紧密;岩浆作用也具双峰式的特点,表现为基性岩浆和酸性岩浆的混合.这为探讨该类花岗岩和环斑结构的成因提供了直接的岩石学依据.同时,也为探讨北秦岭中生代壳幔混合作用和地壳增生提供了新的信息. 相似文献
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在小兴安岭东南端的鹤岗—伊春市交界处大岭一带的晚石炭世弱片麻状中粒似斑状二长花岗岩中发育环斑结构长石,多以呈自形宽板状或宽板柱状的碱性长石内核和斜长石外薄壳组成,少量为不发育斜长石外壳的卵球状、球状,大小为1.5￣3.5cm,其特征与典型的环斑结构在岩相学上是相同的。另外岩体中普遍发育暗色微细粒闪长质包体,与环斑钾长石在时空上紧密相伴;包体具典型的岩浆结构及针状磷灰石,含寄主岩的钾长石、石英巨晶;包体形态多呈浑圆的外形,显示出明显的塑性流变特点,与寄主岩常呈明显的接触关系,有时呈过渡状、雾迷状;以上充分说明了包体为岩浆混合成因(MME)。通过对岩体地质、环斑结构钾长石似斑晶、暗色微细粒闪长质包体等特征及岩体的岩石化学、地球化学研究表明大岭环斑花岗岩岩体为岩浆混合成因,产于造山环境,其形成时代、产出构造背景均不同于典型环斑花岗岩。 相似文献
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秦岭环斑结构花岗岩中暗色包体的岩浆混合成因及岩石学意义——元素和Nd、Sr同位素地球化学证据 总被引：19，自引：10，他引：19
秦岭环斑结构花岗岩中的暗色包体主要为闪长质岩浆包体,SiO2(50％-62％)低,K2O Na2O(7．01％-9．4％) 高,里特曼指数(δ)为5-9,F、过渡性元素和稀土元素富集。包体和寄主岩石的主要氧化物之间具有良好的线性关系、稀土配分曲线和微量元素配分曲线相似,以及活动性组分、高场强元素、轻稀土和同位素特征等显示,寄主岩石和包体之间发生过明显的成分交换,这些成分在二者中大体上趋于平衡。这种特征表明,环斑结构花岗岩岩浆的形成至少与两种岩浆的混合有关。包体的(87Sr／86Sr)i较低(0．70514-0．70624)、εNd(t)值较高(-0．95--3．3)和富过渡性元素的特征揭示,形成包体的原始岩浆为起源于幔源的玄武质岩浆。包体和寄主岩石的关系显示岩浆的混合方式为基性岩浆注入到已经开始结晶的酸性岩浆。这些研究为环斑结构花岗岩是起源于地壳的酸性岩浆和起源于地幔的基性岩浆形成的混合岩浆结晶的产物提供了新证据;同时,也为环斑结构的混合成因研究提供了新思路和途径。 相似文献
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小兴安岭晚石炭世花岗岩岩浆混合作用的岩相学证据及其地质意义 总被引：7，自引：0，他引：7
小兴安岭晚石炭世花岗岩具有明显的岩浆混合特征。岩体中暗色岩浆包体发育,主要为细粒闪长质岩浆包体,包体形态多样、大小不一,与寄主岩石呈截然、模糊或过渡关系。包体的矿物组合明显不平衡,如出现了寄主岩石中的碱性长石捕虏晶,有时可见其具暗色矿物镶边,发育针状磷灰石。这表明小兴安岭晚石炭世花岗岩的岩浆混合表现为基性岩浆和酸性岩浆的混合。这为探讨这些花岗岩的成因提供了岩石学依据,同时也暗示晚古生代佳木斯—松嫩古陆可能发生过地壳的垂向生长。 相似文献
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中川岩体位于秦岭造山带西段,岩体呈同心环状产出,由外向内岩性依次为似斑状黑云二长花岗岩→含斑黑云二长花岗岩→中细粒黑云二长花岗岩,岩体边部发育岩浆暗色包体,向内逐渐减少。LA-ICPMS锆石U-Pb定年结果显示,似斑状黑云二长花岗岩、含斑角闪黑云石英闪长岩(岩浆暗色包体)、细粒黑云二长花岗岩、岩浆暗色包体(无斑)和细粒花岗岩脉的年龄分别为:(221±1)Ma(MSDW=0.26)、(220±1)Ma(MSDW=0.11)、(217±1)Ma(MSDW=0.11)、(216±1)Ma(MSDW=0.26)、(207±1)Ma(MSDW=0.29),表明岩体从边部到中心年龄逐渐变新。寄主岩石与暗色包体的里特曼指数和A/CNK值分别为2.20～3.85、0.99～1.15和2.24～9.22、0.75～1.08,两者分别为准铝质-弱过铝质、高钾钙碱系列和钾玄岩-高钾钙碱系列;稀土元素和微量元素均显示出富集LREE、Rb、Ba、K等大离子亲石元素,亏损HREE、Zr、Hf、Ta、Nb、P、Ti等高场强元素的特征,具有弱的负铕异常(δEu=0.29～0.91),无Ce异常,寄主岩显示出I型花岗岩的特征,并且中心部位的细粒黑云二长花岗岩具高分异I型花岗岩的一些特征。在哈克图解上暗色包体和寄主岩石的主要氧化物具有良好的线性关系;在同位素组成上,寄主岩石与暗色包体的εNd(t)分别变化于-7.31～-8.73和-5.32～-5.69,TDM2分别变化于1.59～1.71 Ga和1.43～1.46 Ga,εHf(t)值分别为-7.02～-0.31和-3.0～0,TDM2为1.27～1.70 Ga和1.2～1.5 Ga,显示寄主花岗岩和岩浆暗色包体分别来源于不同源区,寄主岩石主要是古老地壳物质部分熔融的结果,岩浆暗色包体可能是来自岩石圈地幔,但与寄主花岗质岩浆已发生了一定程度的混合作用。岩体外围金矿床形成略晚于岩体,与花岗质脉岩年龄相近,空间上与岩体密切相关,结合前人成矿物质来源的研究,认为成矿物质与成岩物质具有相似性。表明该岩体与其周围的金矿具有成因联系,岩浆作用不仅提供了热能,也有物质贡献。 相似文献
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阿尔金造山带南缘岩浆混合作用:玉苏普阿勒克塔格岩体岩石学和地球化学证据 总被引：16，自引：8，他引：8
阿尔金造山带南缘玉苏普阿勒克塔格岩体中的似斑状中粗粒黑云钾长花岗岩发育有岩浆成因的暗色包体,并且该花岗岩被花岗细晶岩呈脉状侵入。该岩体含有丰富的岩浆混合作用特征: 如暗色包体中的碱性长石斑晶、针状磷灰石、长石的环斑结构、石英/斜长石主晶和榍石眼斑等。暗色包体、寄主花岗岩和花岗细晶岩代表了岩浆混合演化过程中不同端元比例混合的产物。地球化学特征上,钾长花岗岩和暗色包体的主要氧化物含量在Harker图解中多呈线性变化。暗色包体主要为闪长质,MgO、K2O含量高,为钾玄岩系列,总体上高场强元素不亏损,显示了岩浆混合中的基性端元信息,可能为幔源熔体结晶分异或壳幔物质的混合产物。寄主花岗岩均为准铝质,富碱,为高钾钙碱性系列,亏损Nb、Ta、Sr、P、Ti等高场强元素,高K2O/Na2O,富集高不相容元素,Ga含量高,显示了A型花岗岩的特征,Th/U 和Nb/Ta比值分别介于为6.67~10.96、8.99~11.94,代表了下地壳源区。花岗细晶岩均为钠质、过铝质,TiO2、MgO含量低, Na2O和CaO含量高,具有混合岩浆侵位后分异的特征。岩相学和地球化学特征说明岩浆混合作用对于环斑结构花岗岩的形成起到重要作用。花岗细晶岩中环斑长石的斜长石外环与钾长石内核的厚度比大于钾长花岗岩中的环斑长石,指示混合岩浆在一定的减压条件下更有利于环斑结构的形成。玉苏普阿勒克塔格岩体中的钾玄质暗色包体、高钾钙碱性花岗岩和中钾钙碱性花岗细晶岩代表了岩浆演化不同阶段的产物,反映了一个幔源岩浆和下地壳不断相互作用,引起地壳连续伸展减薄的过程,指示阿尔金南缘在早古生代末期存在造山后伸展背景下的幔源岩浆底侵作用。同一岩体中两种不同时代岩性的环斑结构显示了该岩体形成历史中的一定时空演化关系,代表了伸展过程中不同阶段的产物。 相似文献
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西秦岭糜署岭岩体镁铁质微粒包体的特征及成因 总被引：7，自引：1，他引：7
糜署岭岩体的岩石组合为灰白色似斑状二长花岗岩-花岗闪长岩-石英闪长岩，其中镁铁质微粒包体十分发育。包体密集成群、成带状分布，个体大小悬殊且有定向性。有的包体具有细粒边，有的见冷凝边；包体与寄主岩石在成分、色率以及组构上多呈弱过渡关系，界线模糊；包体中发育斜长石异常环带及针状磷灰石，常有寄主岩石中的钾长石巨晶(捕虏晶)。这些特征提供了基性岩浆与酸性岩浆混合的证据，也为探讨本区中生代壳幔混合作用和地壳增生提供了信息。 相似文献
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黑龙江省张广才岭南部早侏罗世花岗岩具有明显的岩浆混合特征。岩体中暗色微粒包体发育,主要为细粒闪长质岩浆包体,包体形态多样,与寄主岩呈截然、过渡关系。包体的矿物组合明显不平衡,如矿物具有定向排列的特点,斜长石发育自形环带并存在新、老两个世代,发育针状磷灰石。由电子探针对斜长石、角闪石和黑云母等矿物分析结果可知,寄主花岗岩和包体中各主要矿物含量基本一致。岩石地球化学特征研究显示,包体与寄主花岗岩关系密切,两者在稀土元素和微量元素方面也表现为明显的地球化学亲缘关系。这表明张广才岭南部早侏罗世花岗质岩石具有壳幔混合成因特征,暗色微粒包体是由较基性的地幔岩浆进入寄主岩浆中淬火结晶而成,花岗质岩浆的源区主要为新生的地壳物质。 相似文献
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小兴安岭东南金山屯一带晚三叠世二长花岗岩成因及其地质意义 总被引：3，自引：0，他引：3
在小兴安岭东南端金山屯一带,广泛发育近南北向展布的晚三叠世似斑状二长花岗岩岩石组合,岩石中普遍见有暗色微细粒闪长质包体和中-基性脉岩群。对岩体及其包体、中-基性脉岩的宏观、微观特征和地球化学特征的研究表明,包体形态多呈浑圆的外形,显示出明显的塑性流变特点,具典型的岩浆结构包体中见针状磷灰石和含寄主岩钾长石、石英巨晶,具有明显的岩浆混合成因的包体特征;岩体的中-基性脉岩（群）形态多样,与花岗岩的界面或呈小波浪状或呈平直状,并见寄主岩长石斑晶,表现出壳幔混合作用形成的同深成岩墙群特征。该区晚三叠世二长花岗岩具显著的岩浆混合成因特征,其形成可能与碰撞后伸展动力学机制下的基性岩浆底侵作用有关。 相似文献
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根据新提供的Pb同位素组成及岩石地球化学研究成果，本文进一步证实了位于北秦岭北界的明港地区发育的早中生代安山玄武质火山角砾岩岩筒所携带的下地壳捕虏体属于南秦岭。所恢复的南秦岭下地壳剖面自下而上为：底侵成因的变辉长岩-基性麻粒岩(其中含有榴辉岩及辉石岩的透镜体)-酸性麻粒岩。秦岭造山带总体的岩石因模型为：南秦岭(扬子块体)向北拆离俯冲，北秦岭地壳向华北仰冲，华北岩石因呈楔状插入秦岭造山带，拆离面约在中、下地壳之间。南秦岭俯冲岩片延伸的范围在平面上有可能达到400km。 相似文献
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青藏高原综合观测研究站的回顾与展望 总被引：1，自引：1，他引：0
中国科学院青藏高原综合观测研究站从１９８８年建站到１９９８年以来,在各个方面均取得了长足的发展,横向生产性项目的开展和完成不仅解决了部队和地方的实际问题,而且缓和了观测研究站在运行过程中所面临的经费严重不足的问题,同时也为我所冻土专业研究人员提供了在生产中实践的机会,在基础理论研究方面,承担了国家攀登计划项目,国家基金项目,中国科学院重点项目和中国科学院冰冻圈专项项目等的研究工作,在多年冻土变化, 相似文献
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E. M. Korobova 《Geochemistry International》2017,55(13):1205-1282
In his last lifetime essay, “A Few Words about the Noosphere”, Academician V.I. Vernadsky (1944) wrote that all living organisms on the planet, including man, are integral to the biosphere of the Earth, its material and energy structure and cannot be physically independent of it even for a minute. However, the substrate that generates all living beings and is no less tightly bound to the biosphere has always been characterized by a significant geochemical heterogeneity, traced both in the vertical and in the lateral structure of all geospheres.
The present work is devoted to three most important aspects of modern geochemistry and biogeochemistry:
On the basis of theoretical concepts of biogeochemistry and geochemical ecology, formulated in the works of V.I. Vernadsky, A.P. Vinogradov, A.E. Fersman, B.B. Polynov, A.I. Perel’man, M.A. Glazovskaya, V.V. Kovalsky, E. Odum, B. Commoner, E.I. Kolchinskii and others, the author puts forward a hypothesis that there exist two qualitatively different stages in the evolution of the biosphere.The first stage is recognized as the period of natural evolution of the biosphere during which it evolves successively into a more complex and more biogeochemically specialized object. In the course of the geological time, this constantly results, on the one hand, in an increase in species diversity and the perfection of individual species, and, on the other hand, to directed improvement and a greater differentiation of the geochemical conditions of the environment. At this stage, the evolution of all systems of the biosphere that were controlled by the mechanisms of self-organization and self-regulation resulted in the establishment of a dynamic equilibrium, which was responsible for the cycling of all essential chemical elements and therefore providing ecologically optimal geochemical conditions in all ecological niches and for all species and biocenoses inhabiting the biosphere at any given moment.The beginning of the second stage is related to the appearance of reason and qualitative changes in the biosphere caused by the goal-directed activity of the human mind, as an entirely new geological force that appeared to be able not only to disrupt the functioning of natural mechanisms of self-regulation and selforganization, but also to transform the environment in the intersts of a single biological species, Homo sapiens. A direct consequence of this change was the uncontrolled transformation of the natural environment, during which the primary structure (geochemical background) created in the course of billions of years was eventually superimposed by a qualitatively new layer of anthropogenically-derived chemical elements and compounds, thus building an interference pattern of a new geochemical field with which practically all modern living organisms are now forced to interact.An outstanding feature of the new evolutionary stage of the natural environment, called by Vernadsky the noosphere, is that biogeochemical changes at this stage proceed at a rate which exceeds that required for the living matter to adapt to these changes. The result is the disruption of the existing parameters of the biological cycle, leading to the emergence of a significant number of endemic diseases of geochemical nature.The proposed approach was used to prove the anthropogenic genesis of existing geochemical endemic diseases and explain the mechanisms of their appearance. In addition, this approach allowed us to develop a new methodology for mapping zones of ecological and geochemical risk and noticeably simplify the procedure of monitoring distribution and prevention of all diseases of geochemical nature. 相似文献
- — evolution of the ecological and geochemical state of the environment under conditions of a virgin (anthropogenically untouched) biosphere;
- — structural features of the geochemical organization of the modern noosphere;
- — specificity of the interaction of living matter with the environment under increasing anthropogenic load.
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铀钍的地球化学及对地壳演化和生物进化的影响 总被引：10，自引：2，他引：8
本文论述了在含挥发份和贫挥发份条件下Ｕ、Ｔｈ的迁移行为及其对地球和行星演化的影响,并阐述了造成地球独特地质演化历史的原因。提出了Ｕ、Ｔｈ在地球中的迁移模式以及该模式对地壳形成、演化的控制作用和对生物发展演化的可能影响。 相似文献
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利用卫星遥感影像,结合实地调查和测年结果,对共和盆地层状地貌系统进行了解译、分析。研究表明,共和盆地层状地貌系统由山麓剥蚀面、洪积扇面、盆地面以及黄河阶地面构成,其空间结构、物质组成对发生于早更新世早期的青藏运动C幕和中更新世末期的共和运动反映清晰。青藏运动C幕使青藏高原主夷平面在高原差异性隆升中彻底解体,垂直变形量高达1700m。共和运动使黄河在0.11Ma进入共和盆地,其后黄河平均以3.5mm/a的侵蚀速率下切盆地,同时在盆地边部的山前古冲洪积扇以大致相近的速率被抬升,最终导致高差在2000m左右的层状地貌系统的出现。 相似文献
19.
The experimental variogram computed in the usual way by the method of moments and the Haar wavelet transform are similar in that they filter data and yield informative summaries that may be interpreted. The variogram filters out constant values; wavelets can filter variation at several spatial scales and thereby provide a richer repertoire for analysis and demand no assumptions other than that of finite variance. This paper compares the two functions, identifying that part of the Haar wavelet transform that gives it its advantages. It goes on to show that the generalized variogram of order k=1, 2, and 3 filters linear, quadratic, and cubic polynomials from the data, respectively, which correspond with more complex wavelets in Daubechies's family. The additional filter coefficients of the latter can reveal features of the data that are not evident in its usual form. Three examples in which data recorded at regular intervals on transects are analyzed illustrate the extended form of the variogram. The apparent periodicity of gilgais in Australia seems to be accentuated as filter coefficients are added, but otherwise the analysis provides no new insight. Analysis of hyerpsectral data with a strong linear trend showed that the wavelet-based variograms filtered it out. Adding filter coefficients in the analysis of the topsoil across the Jurassic scarplands of England changed the upper bound of the variogram; it then resembled the within-class variogram computed by the method of moments. To elucidate these results, we simulated several series of data to represent a random process with values fluctuating about a mean, data with long-range linear trend, data with local trend, and data with stepped transitions. The results suggest that the wavelet variogram can filter out the effects of long-range trend, but not local trend, and of transitions from one class to another, as across boundaries. 相似文献
20.
The possibility to use some widely known standard discrimination diagrams such as the K2O/Na2O-SiO2/Al2O3, SiO2-K2O/Na2O, (Fe2O3* + MgO)-TiO2, F1-F2, Th-La-Sc, Sc-Th-Zr/10, and Sc/Cr-La/Y for deciphering the paleogeodynamic settings of sedimentary sequences is considered with reference to the Lower and Middle Riphean (Mesoproterozoic) deposits of the Uchur-Maya region (Far East) and the Bashkir meganticlinorium (South Urals). It was shown that only some of them can be used with a certain degree of confidence for reconstructing the settings of the platform sedimentary sequences made up of both sandstones and fine-grained terrigenous rocks. 相似文献