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西秦岭吴家山隆起的隆升过程及时代 总被引：5，自引：2，他引：3
吴家山隆起位于西秦岭印支褶皱带东部 ,由前泥盆纪变质岩系构成 ,其上与泥盆纪西汉水群生物灰岩呈拆离断层接触关系。在变质岩系中可明显观察到最晚的两期构造面理 ,记录了晚华力西 _早印支期的热隆伸展作用和晚印支期的陆内挤压造山运动两次构造事件。吴家山核部变质岩系中获得的角闪石矿物的 4 0 Ar/ 39Ar同位素坪年龄反映出三次构造热变质事件 ,分别为 2 4 9Ma、2 2 0 Ma、180 Ma。因此 ,吴家山隆起的主要隆升时代应为晚华力西 _早印支期 ,并受到晚印支期的陆内挤压造山运动的叠加改造和抬升 ,燕山运动对隆起有较明显的改造作用 ,表现为正断抬升。 相似文献
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滩间山金矿田控矿构造特征 总被引：1，自引：0，他引：1
本文首次研究了滩间山金矿田控矿构造特征。笔者认为含碳堇青石白云母石英糜棱片岩之中的控矿构造在加里东期韧性剪切带基础上发育而成；华力西期，闪长玢岩和煌斑岩脉与糜棱片岩接触部位控矿构造生成，并同上述糜棱岩之中的控矿构造一起经历了韧脆性剪切作用；印支运动之后，控矿构造演化为脆性断裂。金矿的形成富集与控矿构造多期（次）活动密切相关。华力西期韧脆性剪切作用则做出了突出贡献。闪长玢岩、煌斑岩脉接触带韧脆性变形 相似文献
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柴达木盆地北缘(以下简称柴北缘)—东昆仑地区已经勘查发现了一批造山型金矿,它们是加里东和晚华力西—印支复合造山作用的产物。通过柴北缘—东昆仑地区12处造山型金矿中流体包裹体研究发现,该区造山型金矿中发育两种不同的成矿流体:低盐度的H2O-CO2-NaCl-CH4流体和低盐度的H2O-CO2-NaCl±CH4。前者的XCH4、XCO2和XH2O分别为0.14～0.34(平均值0.24)、0.11～0.59(平均值0.34)和0.64～0.31(平均值0.42),温度变化为180～270℃,压力为180～560Mpa,是晚加里东期碰撞造山作用的产物,主要沿加里东碰撞造山带边界的上地壳底部-中地壳上部的塑性变形带大规模流动,并在本区形成了广泛的金矿化;后者的XCH4、XCO2和XH2O分别为0～0.12(平均值0.06)、0.18～0.25(平均值0.21)和0.79～0.69(平均值0.73),温度变化为280～449℃(主要在280～360℃),压力为80～230Mpa,主要与晚华力西—印支期碰撞造山作用有关,其中不少矿床还受侵入岩浆作用的影响,其沿晚华力西—印支期碰撞造山带边界的上地壳大规模流动,导致了本区造山型金矿的最终定位。上述两期成矿流体的盐度相差不大,总体变化在1.4%～11.4%(NaCl)(大部分集中于2.7%～9.1%)。压力-深度换算结果显示,本区晚华力西—印支期碰撞造山作用表现出地壳强烈隆升过程,其最大隆升幅度达12km。这说明该区大规模的造山型金成矿作用发生在地壳隆升的背景之下。 相似文献
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位于松潘—甘孜造山带雅江穹隆群北东部的容须卡岩浆底辟穹隆区,经历了多期构造演化,内部构造极其复杂。为厘清容须卡地区岩浆与穹隆的演化关系,通过野外地质调查及室内综合研究,探讨了容须卡穹隆的地质特征及构造演化。该穹隆中心发育无根或肠状褶皱,及"S"型、"Z"型褶皱和"A"型平卧褶皱;穹隆外围发育叠加褶皱,反映造山带早期SN向和EW向收缩挤压。该穹隆主要经历了晚三叠世(印支末期)SN向与EW向的"双向挤压"作用;成穹期岩浆向上侵位时限为(214.4±1.2) Ma;成穹后经历了挤压推覆和应力松弛阶段;早中新世(17～10 Ma),由于青藏高原东南缘快速抬升,松潘—甘孜造山带发育NW-SE向鲜水河左旋走滑断裂,使容须卡地区形成一系列NNW向韧脆性和脆性破碎带。 相似文献
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青海松树南沟金矿矿床地质特征 总被引：2，自引：0，他引：2
青海松树南沟金矿床位于北祁连山环太平洋型俯冲带(缝合带),产于印支～燕山期花岗闪长斑岩体及其与围岩接触带附近。通过矿床地球物理、地球化学和地质特征综合分析,认为该金矿经历了加里东期火山作用阶段和华力西-印支期岩浆侵入作用阶段,但矿床的最终形成与晚华力西—印支期陆内碰撞造山产生的大规模剪切构造—流体活动使原有成矿物质活化、迁移、富集和沉淀成矿有关,可归类为造山斑岩型金矿床,已探明储量达中型规模,具良好的成矿远景。 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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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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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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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
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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
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N. P. Laverov L. I. Lobkovsky M. V. Kononov N. L. Dobretsov V. A. Vernikovsky S. D. Sokolov E. V. Shipilov 《Geotectonics》2013,47(1):1-30
The tectonic evolution of the Arctic Region in the Mesozoic and Cenozoic is considered with allowance for the Paleozoic stage of evolution of the ancient Arctida continent. A new geodynamic model of the evolution of the Arctic is based on the idea of the development of upper mantle convection beneath the continent caused by subduction of the Pacific lithosphere under the Eurasian and North American lithospheric plates. The structure of the Amerasia and Eurasia basins of the Arctic is shown to have formed progressively due to destruction of the ancient Arctida continent, a retained fragment of which comprises the structural units of the central segment of the Arctic Ocean, including the Lomonosov Ridge, the Alpha-Mendeleev Rise, and the Podvodnikov and Makarov basins. The proposed model is considered to be a scientific substantiation of the updated Russian territorial claim to the UN Commission on the determination of the Limits of the Continental Shelf in the Arctic Region. 相似文献