共查询到20条相似文献,搜索用时 875 毫秒
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《西北地质》2016,(3)
北金齐火山岩盆地是在华力西晚期伸展构造作用下形成的陆相火山岩盆地,切盆及环状断裂发育。铀多金属矿化亦环带状分布于盆地周边,按照含矿建造可分为:赋存于上二叠统库吉尔台组凝灰质砾岩段的铀钼矿化;赋存于下二叠统卡拉岗组熔岩段的铀铜矿化。通过对不同层位的典型矿点特征分析,认为北金齐火山岩盆地铀多金属找矿潜力较大。由于克孜勒阔腊铀钼矿点受酸性凝灰质砾岩及特定的构造位置的控制,笔者指出了2个找矿方向,首先应圈定由酸性砾石构成的含矿凝灰质砾岩带,其次注重寻找深部隐伏的酸性斑岩体及其内外接触带部位的多金属矿化部位;阿尔帕萨勒铀铜矿化点与之配套的隐爆角砾岩、蚀变分带均显示深部具备形成次火山岩型或斑岩型多金属矿化的有利条件。 相似文献
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沽源火山盆地燕山期次流纹斑岩地质地球化学特征 总被引:2,自引:0,他引:2
燕山期次流纹斑岩主要分布在沽源火山盆地盖层的上侏罗统张家口组火山岩中,活动时间以燕山晚期为主.次流纹斑岩体在空间分布上受断裂构造和燕山晚期火山构造控制,与铀钼矿化关系密切,矿化主要产在次流纹斑岩体接触带或其顶部的隐爆角砾岩中.次流纹斑岩与围岩呈侵入接触关系,呈岩株、岩墙、岩脉等形态产出.岩石地球化学研究表明:次流纹斑岩... 相似文献
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沽源火山盆地铀钼多金属成矿地质条件分析及找矿方向 总被引:5,自引:0,他引:5
沽源火山盆地是我国北方重要的铀钼多金属矿勘查基地和矿业开发基地。文章在总结矿床地质特征的基础上,重点分析了多金属矿成矿地质条件、矿化特征和成矿时代以及成矿作用与中生代次火山岩和断裂构造关系。认为在盆地基底变质岩中寻找岩浆热液叠加改造型的层控铅锌银金矿床、在盆地火山岩盖层中寻找火山岩热液型铀钼矿床具有良好的找矿前景。 相似文献
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北金齐火山盆地具有较好的铀矿找矿基础和成矿潜力,其铀矿化特征在新疆北部火山岩带具有普遍性。文章以北金齐火山盆地南、北缘和中部的3条典型铀-多金属矿化带为研究对象,较为全面地阐述了各带地质、矿化及蚀变组合等特征,并通过总结分析区内主要控矿因素及其控矿作用,初步建立了区域铀成矿模式。北金齐地区铀-多金属成矿具多因素联合控矿作用,铀-多金属矿化整体分布受火山盆地及北东东向区域大断裂控制,且盆地南、北缘大断裂较中部火山机构成矿地质条件优越。盆地内大断裂两侧的次级断裂带、裂隙带为主要含矿构造;酸性火山熔岩与酸性凝灰(角)砾岩为主要赋矿岩性,并为铀成矿提供一部分铀源;花岗斑岩等岩浆岩侵入活动为区内铀-多金属矿化主要成矿作用,推测火山机构塌陷后,花岗斑岩等岩浆岩侵入活动带来的含矿流体沿断裂贯入,在有利的构造和岩性中富集成矿。 相似文献
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赣北昆山-大河里地区钨钼矿资源潜力及找矿方向 总被引:1,自引:0,他引:1
赣北昆山—大河里钨、钼矿均富集在同一地层——双桥山群修水组的一套火山碎屑、泥砂质区域浅变质岩系中。矿化富集区处于九岭钨钼矿带内,它们呈北东向展布,主要受北东向构造控制,并与北东向构造的南北向次级断裂带有关。矿化富集区及次一级的矿化富集区中,石英脉发育,地表矿化信息丰富,有寻找和扩大钨钼矿资源的潜力。 相似文献
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东秦岭地区碳酸岩型钼- 铀多金属矿床主要包括华阳川铀多金属矿、黄龙铺和黄水庵钼矿等。其中,华阳川矿床为近期取得勘查突破的一例以U、Nb、Pb为主并伴生稀土元素的超大型铀多金属矿床;黄龙铺钼矿为东秦岭钼矿带中成矿类型最为独特的大型钼矿床。为了精确获得东秦岭地区碳酸岩型钼- 铀多金属成矿时代,本研究采用辉钼矿Re- Os法和LA- ICP- MS独居石U- Pb法,分别对黄龙铺大石沟矿床的辉钼矿、秦岭沟矿床和华阳川矿床含矿碳酸岩脉中的独居石进行测定。结果表明,黄龙铺地区大石沟钼矿辉钼矿Re- Os等时线年龄为221. 3±8. 4Ma(MSWD=10. 9);秦岭沟钼矿碳酸岩中独居石LA- ICP- MS Tera- Wasserburg年龄为207±11Ma(MSWD=3. 7, n =38),华阳川铀多金属矿LA- ICP- MS独居石Tera- Wasserburg年龄为222. 5±6. 7Ma(MSWD=1. 8, n =37),表明该地区碳酸岩中的钼矿化和铀多金属矿化均形成于晚三叠世。综合分析认为,东秦岭地区发育于碳酸岩中的黄龙铺钼矿田、华阳川铀多金属矿是同一成矿系列的产物,碳酸岩型钼- 铀多金属的成矿金属可能来源于地幔,这类碳酸岩可能是秦岭地区印支期造山后伸展环境下的产物。 相似文献
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460铀-钼矿床是冀北沽源中生代火山岩盆地中找到的一个大型中低温热液斑岩型铀-钼矿床。文中阐述了该铀-钼矿床的地质特征,从区域成矿迁移过程和演化历史分析的角度,结合蚀变元素地球化学特征研究,对成矿物质来源进行探讨;总结了矿床的3个主成矿期(24、88和122Ma),具有斑岩型、浸染型、网脉型和表生铀矿化3种矿化类型。对矿床特征及成因进行探讨。通过研究新近纪表生淋积作用在矿体上部地表处附近形成的次生富集带,总结出冀北火山岩地区铀-钼地质找矿工作靶区的判别依据,明确了寻找此类型铀-钼矿床或盲矿体的直接标志。 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