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1.
扬子东南缘北段加里东期的褶皱特征——来自不整合关系的证据 总被引:1,自引:0,他引:1
扬子(地台)东南缘,自江西乐平向北一直缺少上、下古生界之间角度不整合接触关系的报道.本文通过新发现的一系列加里东期角度不整合接触关系,结合下古生界中2期强烈褶皱的变形分析,论证了扬子东南缘北段(浙皖赣相邻区)存在加里东期褶皱. 相似文献
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扬子克拉通南华纪-早古生代的构造-沉积旋回 总被引:5,自引:3,他引:2
根据影响克拉通盆地演化的板块活动所经历的威尔逊旋回,扬子克拉通南华纪-早古生代的构造-沉积旋回可分为5期,即南华纪-震旦纪的均衡调整期、寒武纪的扩张期、早-中奥陶世的汇聚期、中-晚奥陶世的碰撞期和志留纪新一轮的均衡调整期。发生在晚奥陶世的中加里东运动是加里东期最强烈的一次造山运动,而发生在晚志留世的晚加里东运动是一次地壳上升运动;相应的扬子古板块志留纪盆地的构造背景为造山期后的裂谷伸展环境,其原型盆地表现为周缘裂谷盆地与弱伸展的克拉通内盆地相间发育的格局。 相似文献
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本文对江西省的地壳演化问题有了新的认识。提出前加里东期扬子板块与华南板块地壳演化的不均一性;加里东期—印支期扬子板块与华南板块接合和加里东褶皱带,以及燕山期江西地壳演化发展新阶段等看法。 相似文献
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<正> 江西九瑞地区的大地构造位于下扬子台褶带,南与江南地背斜雪峰期褶皱带、北与武当大别雪峰期褶皱带毗邻。九瑞地区加里东运动长期以来系指上志留统西坑组与上泥盆统五通组间的假整合关系。普遍缺失早、中泥盆世的沉积,到晚泥盆世才开始下降,沉积了五通组。岳文浙等(1987)应用沉积相的研究方法,认为本区五通组实际上应划入黄龙组,作为黄龙组的一个岩性段,时代为晚石炭世威宁期。因此,九瑞地区加里东运动的时 相似文献
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湘黔边境加里东板内造山期后正向滑脱构造与成矿 总被引:4,自引:0,他引:4
湘黔边境地处扬子板块东南缘,加里东运动是区内古生代最强烈的板内造山运动;由新元古界板溪群至下古生界奥陶系所构成的NE-NNE向褶皱带为区内主体构造;近期区域地质调查所发现的加里东造山期后,构造体制由挤压转换为伸展所产生的一套正向顺层滑脱构造系统更具特色,不但空间结构完整,构造变形清楚,正向顺层滑脱标志明显,而且成矿控矿作用突出,是湘黔边境著名汞矿带的重要控矿构造. 相似文献
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钦-杭接合带之构造特征 总被引:2,自引:0,他引:2
华南大陆壳由扬子地块和华夏地块两个主要的地质构造单元组成,其间发育一条板块碰撞拼接带——钦-杭接合带,依据地层组成、构造变形差异,进一步划分为鄣公山构造混杂岩带、绍兴-江山对接带,前者叠加发育在扬子地块南部陆缘江南古岛弧之上,后者代表两地块间消减了的大洋及边缘海混杂体,经历了晋宁-加里东多期碰撞拼贴:晋宁期华夏陆块向扬子陆块俯冲、碰撞、走滑,形成了透镜-网结状韧性剪切系统争三期褶皱变形;加里东运动,华夏陆块再次与扬子陆块碰撞、仰冲,导致华南加里东造山带逆冲推覆在晋宁期造山带之上。至此,两者最终焊接成一体,形成了统一的晚古生代沉积盖层。 相似文献
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湘黔桂三角区大地构造位置属扬子地台东南边缘与华南褶皱系的结合部位。全区经过武陵运动、加里东、印支燕山三次广泛的构造活动,规模宏大的褶皱和断裂共同构成了本区构造的主体轮廓。综合前人及本次研究成果,研究区层控型铅锌矿主要控矿岩层有下寒武统、上震旦统、下奥陶统,深大断裂具导矿作用。矿床成因是以下渗古海水等为基础的成矿流体,由于加里东构造运动沿早期或同期的深大断裂迁移到控矿岩层沉淀成矿。 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
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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
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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
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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
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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
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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
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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
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正Artemia cysts are an extremely important component of aquaculture diets.It is well established that the cultivation of fish and shellfish derive substantial health and growth advantages when Artemia are included in the diets of the 相似文献