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阿尔金山喀腊大湾铁矿田位于北东向阿尔金走滑断裂与东西向阿尔金北缘断裂所夹持的地区。通过对已有铁矿床地质特征的研究,确认喀腊大湾地区铁矿床属于火山沉积型,因此,铁矿床具有成带状分布的特点,由八八铁矿床、八八西铁矿床、7914铁矿床、7915铁矿床、7918铁矿床和7910铁矿床共同构成喀腊大湾铁矿田。铁矿田范围内的地层以向北陡倾的单斜层为主,倾角75~88°;仅矿田西段八八西铁矿床、八八铁矿床一带沿走向发生直立陡倾伏(背斜)褶皱,可见地层和含矿岩系局部发生褶皱重复,形成铁矿带和含矿层位呈横卧"勾"状形态。铁矿床的产出严格受火山沉积岩系的特定层位和岩性控制,即铁矿床均产在卓阿布拉克组第三亚组第一岩性段(下部玄武岩段)的上部,其北侧为卓阿布拉克组第三亚组第二岩性段(大理岩段)标志层。与铁矿床关系密切的中基性火山岩锆石SHRIMP U-Pb年龄为(517±7)Ma,显示该套火山沉积岩系中基性火山岩的时代为早古生代晚寒武世,因此,铁矿床的形成(火山-沉积)时代为晚寒武世。铁矿床形成之后主要发生2期地质构造事件,其一是发生了构造变形,致使铁矿体及含铁岩系均呈陡立状态,并形成褶皱;其二是中酸性岩浆侵入活动,使已经形成的铁矿床受到中酸性侵入岩的吞食破坏,并发生接触变质矽卡岩化改造。矽卡岩化改造时代为早奥陶世末期(辉钼矿铼锇等时线年龄480 Ma)。 相似文献
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阿尔金山喀腊大湾地区中酸性侵入岩SHRIMP年龄及其意义 总被引：11，自引：5，他引：6
阿尔金山东段喀腊大湾地区位于北东向阿尔金走滑断裂北侧与东西向阿尔金北缘断裂所夹持的区域,该区广泛发育中酸性侵入岩,前人将其确定为晚古生代。本文运用锆石SHRIMPU-Pb方法对该区的中酸性侵入岩进行测年,获得413～514Ma的年龄,确认喀腊大湾地区早古生代岩浆活动的存在。结合前人其他方法测年数据和红柳沟一带(喀腊大湾以西180km)中酸性侵入岩的SHRIMP测年资料和蛇绿岩的时代,将阿尔金山东段喀腊大湾地区中酸性岩浆活动划分为碰撞前岩浆活动(520～500Ma)、碰撞期岩浆活动(490～470Ma)和碰撞后岩浆活动(440～410Ma)三个阶段。 相似文献
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阿尔金山北缘喀腊大湾地区早古生代中酸性侵入岩岩石地球化学特征及构造意义 总被引：1，自引：0，他引：1
喀腊大湾地区位于阿尔金山脉东北缘,当地早古生代时期构造环境复杂并且伴随剧烈的花岗质岩浆活动.通过对区域内早古生代中酸性侵入岩5个岩体（大平沟岩体、阿北银铅矿岩体、阿北岩体、4337北花岗岩体、喀腊大湾南岩体）的岩石学、岩相学、地球化学特征研究,探讨早古生代区域重大构造事件和构造环境.南部的喀腊大湾南岩体表现低钾性质,其余4个岩体样本为中高钾钙碱性中酸性岩,并且有向高钾演变的趋势,铝饱和指数在1.0~1.1之间,数据统计和分析大部分样品具有I型花岗岩特征,少部分显示了I型向S型过渡的性质,代表了洋壳-陆壳活动性大陆边缘的环境.结合喀腊大湾周边地质背景,本地区应该是阿尔金古洋壳和塔里木地块南北向碰撞作用的火山岛弧区域. 相似文献
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喀腊大湾铁矿是近年来在阿尔金地区发现的超大型铁矿,目前控制储量近亿吨,且该铁矿具有品位高,低硫低磷等特点。由于矿床围岩的特殊性,该矿床的成因一直存在较大争议。利用Re-Os同位素定年方法,对喀腊大湾矿体中的5件辉钼矿样品进行了成矿时代测定,获得辉钼矿Re-Os同位素模式年龄为490±11Ma,等时线年龄为481.9±7.6Ma。二者在误差范围内基本一致。该年龄与成矿相关岩体的SHRIMP锆石U-Pb年龄488±5Ma及479±4Ma吻合,且发现的矿体附近都有闪长岩体出露,表明成岩和成矿关系密切。结合岩石学、矿物学及年代学特征,认为喀腊大湾铁矿为矽卡岩矿床。 相似文献
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新疆维吾尔族自治区若羌喀腊大湾一带铁矿勘查区地处塔里木板块的塔里木古陆缘地块与塔里木南缘活动带接合部位,位于阿尔金金、铜镍及多金属、铁、稀有稀土金属成矿带内。根据区内铁矿床的成矿地质特征、铁矿石的结构构造、矿物组分特点进行综合分析,认为勘查区内铁矿床的成因为火山喷溢-岩浆热液改造加富海相火山岩型铁矿床。 相似文献
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华北陆块铁矿床地质特征和资源潜力展望 总被引：8，自引：0，他引：8
华北陆块是我国重要铁矿资源的分布区,铁矿石主要开采区,也是我国钢铁工业的重要分布区。区内保有铁矿资源储量299.48亿吨,占全国总资源储量51.94%。区内各省市的铁矿资源分布极不均匀,以辽宁、河北、山西三省铁矿资源最为集中,其资源储量达220.26亿吨,占全区总铁矿资源储量75.55%。区内矿床类型较为齐全,主要的有(火山)沉积变质型铁矿床、接触交代型铁矿床、岩浆型铁矿床、复合成矿作用型铁矿床、沉积型铁矿床、热液型铁矿床、海相火山岩型铁矿床等,其中以(火山)沉积变质型铁矿床最为重要,其资源储量占全区总资源储量84.02%;其次为邯邢式接触交代型铁矿床,资源储量占全区总资源储量6.19%。该区铁矿床从太古宙到新生代都有产出,但不同地质时期产出铁矿床类型和规模不尽相同,并与区内地壳演化的特征紧密相关。太古宙是区内最重要的地质时期,该时期形成铁矿资源储量占总资源储量79.87%,广泛分布在各古老结晶基底的变质岩系内。其次为元古宙和中生代,它们资源储量分别占总资源储量的12.6%和7.06%。该区铁矿资源寻找的主要类型是条带状铁建造型铁矿床,其次是邯邢式。除上述两个主要类型外,各省根据各自地质特征,对河北岩浆型大庙式,山东热液型朱崖式等其它铁矿类型,也需要进行地质找矿。该区资源潜力还是较大的。 相似文献
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《地学前缘》2015,(4)
喀腊大湾地区地处新疆若羌县境内,在区域上位于北东向阿尔金走滑断裂北侧与东西向阿尔金北缘断裂所夹持的区域,属于红柳沟—拉配泉一级成矿带的中东段部分。研究表明,喀腊大湾地区构造控矿作用明显。首先,大地构造背景控制一级矿带的分布和位置,阿尔金断裂400km左右走滑位移量将北祁连山西段成矿带左行断错至目前位置,构成了区域上红柳沟—拉配泉一级成矿带。第二,区域构造环境控制二级矿带、矿床类型和矿种类型,喀腊大湾矿集区南带南侧岛弧构造环境控制与中酸性火山岩有关的块状硫化物矿床(类VMS型),南带北侧弧盆过渡带构造环境控制与中基性火山岩有关的铁矿床,中带盆地构造环境控制与沉积岩有关的硅铁建造型铁矿床,北带南侧蛇绿混杂岩带控制与洋壳残留(基性超基性岩)有关的铜镍矿床,北带北部碰撞变形带控制与强烈韧性韧脆性变形有关的金矿床和与岩浆侵入作用有关的热液银铅矿床。第三,构造演化不同阶段具有不同的控矿作用,主要成矿作用发生在早古生代,其中:(1)新元古代晚期—早古生代早期,红柳沟—拉配泉弧后盆地(裂谷)拉张扩张时期,主要形成与中基性火山沉积作用有关的铁矿床;(2)早古生代中期为红柳沟—拉配泉弧后盆地(裂谷)俯冲碰撞作用和最后挤压闭合,形成与中酸性岛弧火山岩有关的矿床(类VMS型)(如喀腊达坂铅锌矿和喀腊大湾铜锌矿)、与大规模韧性韧脆性变形带有关的金矿床(如大平沟金矿)和与岩浆侵入活动有关的矿床(中酸性火山岩477~488 Ma,中酸性侵入岩417~514 Ma)。第四,典型构造控矿形式有火山沉积构造控矿(铁矿、铅锌矿)、韧脆性剪切带控矿(金矿)、断裂裂隙控矿(银铅矿、铜银矿)、岩体及岩体构造控矿(铜镍矿)4种类型。 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