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羌塘盆地北部布格重力异常对深部结构和密度变化反应敏感,密度较低的深部油储能够导致布格重力显著减小,密度较高的深部玄武岩能够引起布格重力明显增加.基于野外观测和钻探标定形成二维地震反射解释剖面,以岩石地层的几何参数和密度为约束,建立羌塘盆地北部正反演模拟初始模型;采用Model Vision软件,通过人机交互反复试算,拟合布格重力异常,进行重力-地震联合反演.结果表明,北羌塘凹陷南部龙尾错—阿木错布格重力低值异常区,中侏罗统布曲组中上部发育厚层油储,平均埋深 ～1700 m,厚度～480 m,密度2.48 g/cm3,含油率～10％,对应布格重力变化为?8 mGal;白滩湖地区三叠系顶部发育透镜体状玄武岩,埋深5800～6300 m,对应布格重力变化变化为+2 mGal.根据布格重力异常及重力-地震联合反演,预测北羌塘凹陷龙尾错—阿木错地区深部发育厚达数百米的油藏,具有发现超大型油田的勘探前景. 相似文献
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为了深入研究硬岩型铀矿化(点、带)的地球物理特征,在桃山、红山子地区开展了综合物探测量.结果表明,在△T磁异常平面等值线图中,铀矿床(点、带)一般位于强弱磁异常过渡地带偏弱磁异常一侧,电阻率断面图中多位于高低阻梯度变化带或中低阻区,电阻率平面图中多位于中低阻过渡带偏低阻一侧.该硬岩型铀矿化地球物理特征为寻找该类铀矿有利地段提供了重要信息. 相似文献
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山东西北部齐河—禹城矿集区矽卡岩型铁矿找矿工作取得了重大突破。该矿集区发育明显的航磁和重力异常,二者具有同源特征。地球物理异常查证工作显示,该区深部发育矽卡岩型铁矿床,成矿时代为早白垩世,铁矿物质主要来源于闪长岩体。铁矿体为地层、侵入岩和构造三者控矿,即铁矿体赋存于奥陶系（石炭系、二叠系）地层、闪长岩体、地层与岩体接触带附近。勘查表明,总体表现为布格重力异常梯度较陡处、剩余重力异常高值处、磁异常较高处、化极磁异常高值处以及高低电阻率转换带是该矿集区矽卡岩型铁矿的找矿有利地段。 相似文献
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海拉尔盆地阿拉尔-罕达盖重磁电剖面深部结构特征及其地质意义 总被引：2，自引：0，他引：2
通过电磁场偏移成像处理技术,探索地震屏蔽层以下深部地质构造特征,揭示了海拉尔盆地深部存在似层状的电性异常,具有复式背斜的构造形态。盆地内各凹陷具有重力低、磁力高、电阻率低的重磁电特征;沉积地层为低频低幅度磁异常,岩浆岩为高频高强度的磁异常;剖面中东部电阻率存在低-高-低3层结构,岩浆岩呈高电阻率特征,古生界呈中低电阻率特征。德尔布干断裂与乌奴尔-鄂伦春断裂控制了深部古生界分布,古生界埋深为2～6 km,厚度为2～4 km;古生界与元古宇的接触界面呈复式背斜的构造形态,由3个背斜构造组成,对浅部凹陷分布有一定的控制作用。海拉尔地区晚古生代石炭纪发育泥岩、页岩、灰岩、板岩,推测盆地覆盖区可能具有一定的油气勘探前景。 相似文献
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为了较准确地选取重力地改中的地层密度值,针对“剖面法”中选取剖面条数的局限性,笔者采用“面积法”,考虑到了全区范围内地层密度对重力值的影响,使得选用的地层密度值更具代表性.该方法在四川西部某重力工区重力地改中的应用中取得了较好效果,极大地降低了地改后的布格重力异常与地形的相关性.该方法通过选用一定数值区间内的不同密度值,对实测重力值重新进行改算和地形改正,得到不同地层密度下的布格重力异常,借用重磁相关分析的方法原理,对布格重力异常与地形高程进行相关性分析,选取相关性最小的地层密度作为该区地形改正密度. 相似文献
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鞍山齐大山矿集区存在2条明显的磁异常带:一条为齐大山露天开采铁矿引起的异常带,另一条为齐大山铁矿西侧的陈台沟深部隐伏铁矿体引起的磁异常带,结合铁矿区地质特征和岩(矿)石物性特征,对矿区地面高精度磁测数据开展综合研究。8个不同高度上延断面磁异常等值线图显示,磁异常形态具上窄下宽特征,总体形态未发生大的改变,上延3 000m的异常强度仍然超过5 000nT;磁法数据的小波分析表明,在四阶细节等值线图中的2条磁异常带合二为一,而五阶逼近值线图反映的磁源体深度为2 647m,推测其下为区域背景场特征;对3760剖面线开展的2D/2.5D人机对话式的拟合反演和3D正演研究的结果均表明,西侧的陈台沟隐伏铁矿与东侧的齐大山铁矿在-3 000m以上呈向形形态连接,推测2个铁矿体的深部连接部分存在厚大的磁铁贫矿体或富铁矿体,预测矿区深部仍然存在铁矿资源找矿潜力。 相似文献
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四川甲基卡矿田是中国乃至世界上锂辉石资源量最集中的地区之一,近年来发现的新三号脉(X03)的氧化锂资源量达88.55万吨,是亚洲第一大锂辉石单脉。文章在多年实践工作的基础上,总结了新三号脉(X03)的重力、磁法、电法综合物探特征,发现新三号脉(X03)具有以下综合地球物理特征:①重力成果显示其位于布格重力梯度带、剩余重力低异常区域;②磁法成果显示其位于地磁化极梯度带、磁源重力低异常区域;③电法方面,大功率激电中梯成果显示其位于视电阻率南北向高异常分布区域;测深成果显示其位于浅部视电阻率高异常中,深部分布有规模和强度更大的视电阻率高异常。这些地球物理特征与脉体的规模、埋藏深度、延伸长度等地质特征相一致。同时,野外地质特征发现已知含矿脉体主要呈南北向分布,因此,可将南北向分布的视电阻率高异常区作为下一步勘探的重点。 相似文献
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鲁西金刚石原生矿床成矿背景复杂，由于缺乏地壳结构、岩浆侵入体位置、断裂规模等信息作为参考依据，深部构造特征及其在成矿过程中的作用尚不明确。本文基于重磁数据和地震剖面资料，采用Parker Oldenburg界面法、功率谱法和2. 5D重磁震联合反演等方法，获得了鲁西地区地壳结构、断裂规模、岩浆侵入体位置等信息，在此基础上，探讨了金刚石原生矿床的深部构造背景。结果表明：鲁西金刚石原生矿床分布于区域布格重力异常低值区、磁异常中 低值区，布格重力异常平均值低于-100×10-5m/s2，磁异常变化范围较大，介于-160~60 nT之间；矿床位于莫霍面、居里面等值线密集的梯度带，即稳定区域与活化区域的过渡带，莫霍面深度约为31. 2~32. 2 km，居里面深度约27. 5~30 km；矿床分布区NW向断裂构造切割深度均超过20 km，其中蒙山断裂切割深度为35 km，深达上地幔，新泰 垛庄断裂切割深度为28. 5 km，深达居里面，泰山 铜冶店断裂切割深度为20. 5 km；金伯利岩于古生代形成后，受中生代伸展构造影响，被NW向断裂逐级抬升、剥蚀，直至出露地表。金刚石品位自南向北逐渐降低是由于北部抬升幅度大，剥蚀接近金伯利岩根部的结果，指示南部矿带找矿潜力大。 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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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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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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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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南海位于印度板块、欧亚板块和太平洋板块之间,是世界上最大的边缘海,其构造位置处于太平洋构造域和特提斯构造域,地质构造复杂.关于南海形成演化的动力学机制存在有多种不同观点,其中最重要的一个观点是印度板块与欧亚板块的碰撞致使华南地块和印支地块地幔物质沿东南方向蠕动,从而导致南海的海底扩张.从特提斯的演化规律,以及新特提斯的闭合过程来看,南海并不是特提斯洋的残留海,而是新特提斯在闭合过程中配合印度板块与欧亚板块碰撞导致华南地块和印支地块地幔物质东南方向蠕动的动力学机制下,在南海重新活化的结果. 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.