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中国大陆科学钻探主孔100～2000米超高压变质岩岩相学特征与变质变形史 总被引：13，自引：14，他引：13
中国大陆科学钻探工程的实施，为超高压变质带的研究打开了新的生面，加深了对苏鲁超高压变质带的认识。从100～2000米获得的岩心的岩石学观察，得知主要岩石类型有：(1)榴辉岩及石榴辉石岩；(2)榴辉岩质片麻岩；(3)石榴橄榄岩；(4)黑云(角闪)二长片麻岩和(5)碎裂岩等。榴辉岩可分幔源和壳源两类，壳源榴辉岩在钻孔中分布较广，上部最为集中；幔源榴辉岩，包括石榴辉石岩，在空间上与超镁铁岩有密切共生关系。榴辉岩质的片麻岩是一种中酸性的超高压岩石，与壳源的榴辉岩共生，显微镜下可以追索出它们之间的结构演化关系。石榴橄榄岩以石榴单辉橄榄岩为主，是俯冲带上部地幔楔加入于俯冲板片变质而成。石榴橄榄岩中的石榴子石富镁，单斜辉石为绿辉石并常含钛斜硅镁石，说明其经过超高压变质的过程。从变质岩石的组合，面理和线理产状的差异，地震反射面和构造角砾岩带的发育，发现以1600米为界，可大致分为2个岩片。上部岩片中多金红石榴辉岩而且出现频率很高，下部岩片中多为多硅白云母榴辉岩出现频率较低。由于隆升进入中下地壳，超高压变质岩普遍发生退变质。榴辉岩的早期退变质成为具后成合晶结构的石榴角闪岩，榴辉岩质片麻岩退变质形成绿帘黑云(角闪)斜长片麻岩，变质条件为角闪岩相，它可以部分熔融或受到钾交代作用而转变为黑云角闪二长片麻岩。后期的伸展造成了局部碎裂和角砾岩带，新生矿物为绿泥石，方解石和赤铁矿、绿帘石等，属绿帘角闪岩相和绿片岩相。主孔100～2000米的超高压变质岩石组合的确定，进一步说明了巨量的地壳物质可以深俯冲进入地幔并迅速折返；超高压变质岩石记录了陆壳俯冲折返和壳幔相互作用的过程，它们是板块下覆构造和地幔动力学的信息载体。 相似文献
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中国大陆科学钻探主孔榴辉岩类岩石退变质过程——对超高压变质地体隆升的启示 总被引：6，自引：11，他引：6
中国大陆科学钻探的实施，揭示了深俯冲陆壳的三维结构。超高压变质岩的岩相学详细观察，发现榴辉岩类岩石占0—2000米岩心的60％。大多数榴辉岩的原岩具有长期居留地壳的历史，但是分布在607～783米附近的石榴单斜辉石岩，在成因上与石榴橄榄岩关系密切。从矿物成分，岩石化学特征上看他们构成超镁铁-镁铁质的岩浆杂岩，是俯冲过程中，地幔物质加入于深俯冲的岩片并一起遭受超高压变质作用。榴辉岩质的片麻岩，部分相当于所谓的副片麻岩，在主孔也占一定的地位。实际是中酸性成分的火成岩超高压变质的产物。花岗质片麻岩有多种类型，根据其中所夹的角闪黑云片岩残留体看来大部分应属角闪黑云斜长片麻岩选择性部分熔融的产物。榴辉岩类的变质演化可分为3个阶段。第一阶段(M1约230—240Ma)是超高压变质的峰期，其证据是石榴石、绿辉石、金红石中均发现柯石英的微粒包裹物，石榴橄榄岩中的钛斜硅镁石是其超高压变质历史的见证。第二阶段(M2，226—219Ma)早期退变质阶段，超高压变质岩退变为高压榴辉岩相和角闪岩相岩石，冠状体和后成合晶的生长是此阶段的标志，这些特征性结构反应了岩石的不平衡和再平衡的历史，说明了超高压变质地体的快速隆升。后来(219～180Ma)超高压变质地体长期处于中下地壳，在流体影响下，榴辉岩质片麻岩退变成的黑云角闪斜长片麻岩及绿帘黑云(角闪)片麻岩，他们经选择性部分熔融或经超临界流体的K交代作用转变为黑云角闪二长片麻岩(即所谓正片麻岩)。其中多含有铈褐帘石，成分环带明显，La／Ce=0．42—0．72，且边沿均有绿帘石的边，代表后期叠加的绿帘钠长角闪岩相退变质。第三阶段(M3：170—180Ma)以糜棱岩和构造角砾岩的出现为特征，代表与二次隆升的脆韧性脆性变形的过渡，这些构造岩的基质普遍发育绿泥石、阳起石和方解石，说明了绿片岩相的退变质。所有上述3期的变质作用均与榴辉岩所经历的构造过程相关。显微结构分析可以揭示结晶作用和变形作用之间的相对时序。基于现今已发表的同位素年代学数据可以将苏鲁地区中生代不同阶段的变质作用与构造过程相互联系起来。CCSD主孔所见的变质演化和相关的变形事件对中国大陆中生代大陆动力学提供如下启示；可以肯定华北和杨子两个板块在三叠纪的碰撞(-240Ma)必然引起巨量地壳物质深俯冲至地幔深度，发生超高压变质。超高压变质岩的早期退变质是一个绝热隆升的过程，而后长期滞留中下地壳，发生部分熔融，接着引发进一步的隆升导致伸展体制，伴随以绿帘钠长角闪岩至绿片岩相的退变质。 相似文献
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安徽省潜山县韩长冲地区的地质构造特征 总被引：2，自引：0，他引：2
韩长冲地区主要由超高压变质岩、碱长花岗片麻岩、二长花岗片麻岩组成。前者包括超高压片麻岩、大理岩、榴辉岩和石英硬玉岩等。其中存在由黑云斜长片麻岩、石英硬玉岩、大理岩及层状榴辉岩组成的超高压变质表壳岩组合。超高压变质岩先后经过柯石英榴辉岩相、石英榴辉岩相、角闪岩相及绿片岩相多阶段的变质作用;经过榴辉岩相、角闪岩相、角闪岩相后及脆性等四期变形。其中角闪岩相变形形成本区的主要构造要素,以发育大量Ａ型褶皱及普遍的糜棱岩化为特征。碱长花岗片麻岩及二长花岗片麻岩只经过角闪岩相及其后的变质和变形作用。超高压变质岩与碱长花岗片麻岩呈侵入接触,可能沿缓倾向ＳＳＥ的韧性剪切带逆掩于二长花岗片麻岩之上。 相似文献
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大别山产出的榴辉岩相岩石包括石榴橄榄岩、榴辉岩、榴云片岩、榴辉片麻岩、榴玉英岩和榴辉大理岩等不同系列,它们均分布于花岗质片麻岩中。矿物共生序列研究表明,榴辉岩相岩石经历了从绿帘角闪岩相、柯石英榴辉岩相、角闪榴辉岩相、绿帘角闪岩相到绿片岩相的演化过程。花岗质片麻岩及变质火山—沉积岩系并未经历超高压变质作用,但却与榴辉岩相岩石经历了同一期绿帘角闪岩相变质事件,证明二者在地壳范围内发生了构造合并 相似文献
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中国大陆科学钻探工程预先导孔中片麻岩-花岗质片麻岩的岩石学和地球化学研究 总被引：8，自引：6，他引：8
中国大陆科学钻探工程预先导孔(CCSD-PP1)中岩心的岩性十分复杂,主要由片麻岩-花岗质片麻岩、超基性岩、榴辉岩及少量多硅白云母石英片岩、斜长角闪岩及角闪云母片岩组成。其中片麻岩-花岗质片麻岩是最重要的岩石类型。根据片麻岩的岩相学及其地球化学特征,确定片麻岩类岩石的原岩为一套具有较高成熟度的碎屑沉积岩-低成熟度的酸性火山岩、碎屑沉积岩建造,并与在其内部里夹层形式存在的榴辉岩一起经历了超高压变质作用。花岗质片麻岩可分为三种类型:绿帘黄铁二长花岗质片麻岩、绿带黑云二长花岗质片麻岩和绿帘二云二长混合片麻岩。绿帘黄铁二长花岗质片麻岩SiO_2含量最高,为76.72％～78.86％,具有强烈的负Eu、Ba异常,Eu/Eu~*=0.125,Ba/Ba~*=0.095～0.396,其稀土和微量元素的配分模式与具有极高成熟度碎屑沉积岩部分熔融而成的花岗岩性质十分相似。该类花岗质片麻岩可能在苏鲁超高压变质带形成之前,由具有极高成熟度的碎屑沉积岩部分熔融而成的岩浆,侵入到片麻岩类的表壳岩中,并经历了超高压变质作用。绿帘黑云二长花岗质片麻岩、混合片麻岩的SiO_2含量明显偏低,且稀土、微量元素配分模式明显不同于绿帘黄铁二长花岗质片麻岩,该类岩石可能由片麻岩类岩石在超高压变质作用峰期阶段和近等温减压第一阶段深 相似文献
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中国大陆科学钻探工程预先导孔中片麻岩—花岗质片麻岩的岩石学和地球化学研 总被引：2，自引：0，他引：2
中国大陆科学钻探工程预先导孔（CCSD－PP1）中岩心的岩性十分复杂，主要由片麻岩－花岗质片麻岩、超基性基、榴辉岩及少量多硅白云母石英片岩、斜长角闪岩及角闪云母片岩组成。其中片麻岩－花岗质片麻岩是最重要的岩石类型。根据片麻岩的岩相学及地球化学特征，确定片麻岩类岩石的地为一套具有较高成熟度的碎屑沉积岩－低成熟度的酸性火山岩、碎屑沉积岩建造，并与在其内部呈夹层形式存在的榴辉岩一起经历了超高压变质作用。花岗质片麻岩可分为三种类型：绿帘黄铁二长花岗质片麻岩、绿帘黑云二长花岗质片麻岩和绿帘二云二长混合片麻岩。绿帘黄铁二长花岗质片麻岩SiO2含量最高，为76．2％－78．86％，具有强烈的负Eu、Ba异常，Eu/Eu^*=0.125,Ba/Ba^*=0.096-0.396，其稀土和微量元素的配分模式与具有极高成熟度碎屑沉积岩部分熔融而成的花岗岩性质十分相似。该类花岗质片麻岩可能在苏鲁超高压变质带形成之前，由具有极高成熟度的碎屑沉积岩部分熔融而成的岩浆，侵入到片麻岩类的表壳岩中，并经历了超高压变质作用。绿帘黑云二长花岗质片麻岩、混合片麻岩的SiO2含量明显偏低，且稀土、微量元素配分模式明显不同于绿帘黄铁二长花岗质片麻岩，该类岩石可能由片磨岩类岩石在超高压变质作用峰期阶段和近等温减压等一阶段深熔作用而成。该项研究对于深入探讨苏鲁超高压变质带变质作用－岩浆作用相互间的成因关系及其动力学过程有着重要的意义。 相似文献
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“阿尔金山岩群”的组成及其构造意义 总被引：18，自引：4，他引：18
以往文献所谓的“古元古代阿尔金山岩群”主要由3种岩石组合组成。第一种为英云闪长质—花岗闪长质片麻岩,占出露面积的70%左右;第二种为副变质岩系,占出露面积的25%左右,包括以夕线石榴片麻岩为代表的高温低压变质岩和以蓝晶石榴片麻岩为代表的高压变质岩;第三种为呈透镜体状分布在前二者中的榴辉岩、石榴斜长角闪岩和基性超基性岩石,占出露面积的5%以下。这种组成表明“古元古代阿尔金山岩群”不具有“岩群“的意义,而是碰撞杂岩带。“阿尔金山岩群”在岩石组合特征、含有榴辉岩、超基性岩石透镜体和榴辉岩的变质年代方面都与柴达木盆地北缘具有可比性,分析“阿尔金山岩群”是柴达木盆地北缘碰撞杂岩带的西延部分。 相似文献
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柴北缘前震旦纪地层系统的新认识 总被引：9，自引：0，他引：9
柴北缘的变质基底具有复杂的岩石组成,除成因迥异的多期变质深成侵入体外,还包括变质程度不同的表壳岩。南带的沙柳河、鱼卡河等地出露大理岩、石英岩、含石榴石片岩和条带状斜长角闪岩等以副变质岩为主的表壳岩系,共同构成了中元古界沙柳河岩群;而出露在北带全吉山、德令哈等地的中高级变质表壳岩系,则为形成于古元古代并具有较强的钾质混合岩化的达肯大坂岩群。柴北缘的榴辉岩分布在南带,除以规模较小的透镜体状赋存于新元古代花岗片麻岩中外,还和沙柳河岩群共生,但在北带的达肯大坂岩群中没有出现。全吉群的时代为南华纪至震旦纪。 相似文献
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柴达木盆地北缘“达肯大坂群”的再厘定 总被引：39，自引：12，他引：39
柴达木盆地北缘原划为古元古代的“达肯大坂群”出露相当广泛,不仅包含了变质程度不同的表壳岩,而且包括了时代迥然不同的变质深成侵入体。原“达肯大坂群”至少有四种类型的岩石组合:其中德令哈杂岩形成时代最老,为古元古代早期的产物;厘定后所称的达肯大坂岩群为一套中至高级变质、并以副变质岩为主的表壳岩系统,推测其形成时代为古元古代晚期至中元古代;第三套岩石组合为花岗片麻岩,主要形成于新元古代早期,不属于沉积地层范畴,其中大量出现榴辉岩包体;榴辉岩除以规模较小的独立包体形式赋存于新元古代花岗片麻岩中外,还和大理岩、石英岩、含石榴石片岩共生在一起,在花岗片麻岩中形成规模较大的残块,这些榴辉岩及与其共生的表壳岩共同构成鱼卡河或沙柳河岩群。 相似文献
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东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。 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
13.
郯庐断裂南段研究进展与断裂性质讨论 总被引：13，自引：3，他引：13
据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。 相似文献
14.
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
15.
16.
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
17.
Jiayu Rong Michael Melchin S. Henry Williams Tatyana N. Koren Jacques Verniers 《《幕》》2008,31(3):315-318
The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs. 相似文献
18.
Dean S. Oliver 《Mathematical Geology》1998,30(7):911-933
In reservoir characterization, the covariance is often used to describe the spatial correlation and variation in rock properties or the uncertainty in rock properties. The inverse of the covariance, on the other hand, is seldom discussed in geostatistics. In this paper, I show that the inverse is required for simulation and estimation of Gaussian random fields, and that it can be identified with the differential operator in regularized inverse theory. Unfortunately, because the covariance matrix for parameters in reservoir models can be extremely large, calculation of the inverse can be a problem. In this paper, I discuss four methods of calculating the inverse of the covariance, two of which are analytical, and two of which are purely numerical. By taking advantage of the assumed stationarity of the covariance, none of the methods require inversion of the full covariance matrix. 相似文献
19.
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
20.
Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base. 相似文献