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1.
阿尔金山北缘恰什坎萨依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夹持的区域,是区域上红柳沟-拉配泉构造带的西段。该区广泛发育火山沉积岩系,前人将其确定为奥陶系拉配泉群,并划分为下岩组(火山岩组)、中岩组(碎屑岩组)和上岩组(碳酸盐岩组)。通过野外地质调查与局部填图,在恰什坎萨依沟、沟口泉铁矿、贝壳滩等地,发现厚层碳酸盐岩以不规则顶盖状出露在较高山顶或山脊上,并与碎屑岩或火山岩呈低角度断层接触关系,构成典型的飞来峰构造。该火山岩组和碎屑岩组已被归为奥陶系,但碳酸盐岩组一直没有精确的生物地层年代依据。综合研究认为,碳酸盐岩应该属中元古界,原来的拉配泉群可能要解体。结合截切推覆构造的冰沟岩体时代,认为推覆构造形成于中—晚奥陶世。该认识与本区在中—晚奥陶世发生裂谷(弧后盆地或有限洋盆)闭合、板块碰撞的区域构造环境和演化历史吻合。  相似文献   

2.
甘肃中西部龙首山一带“韩母山群”的重新厘定   总被引:3,自引:0,他引:3  
关于甘肃龙首山一带“韩母山群”的划分和时代归属,前人曾有不同的认识。依据沉积建造、古生物化石、变质变形等资料,对韩母山群进行解体。将该群下部变质变形较强的烧火筒沟组(钙质砾岩、细碎屑岩夹碳酸盐岩建造)厘定为震旦系,上部变质变形较弱的草大坂组(碎屑岩、碳酸盐岩建造)厘定为寒武系,并将后者与鄂尔多斯西缘下、中寒武统对比。  相似文献   

3.
牛绍武  张鹏远  孙淑芬  刘永顺 《地质通报》2016,35(11):1753-1770
内蒙古白云鄂博地区具有世界上最大的稀有-稀土铁矿床,关于其时代归属尚存分歧。在都拉哈拉组(H3)与尖山组(H5)发现丰富的早寒武世微古植物化石,在尖山组(H5)硅质岩中发现早寒武世小壳化石,在哈拉霍疙特组(H8)确认了奥陶纪床板珊瑚的存在(包括块状群体与丛状群体),并首次发现大型古钵海绵化石与遗迹化石,在比鲁特组(H10)鲍玛序列中发现遗迹化石。初步确认,内蒙古商都地区三足化石(腕足类、头足类与腹足类)的层位可能为呼吉尔图组(或哈拉霍疙特组)。多门类化石的发现与确认,为重新认识白云鄂博超大型稀有-稀土铁矿床含矿地层时代提供了确凿的古生物化石证据,也为重新认识白云鄂博超大型稀有-稀土铁矿床的成矿地质背景开辟了新的研究思路,具有重要的地层学与大地构造学意义。根据多门类古生物化石组合与时代,将原白云鄂博群下部(H1~5)重新厘定为狭义的白云鄂博群,时代为早寒武世;原白云鄂博群上部(H6~15)重新命名为宽沟群,时代为早—中奥陶世,其间的假整合可能就是吉—黑地区的兴凯运动面。重新厘定的白云鄂博群与宽沟群一并划归天山-兴安地层区内蒙古草原地层分区,它是天山-兴安古生代海槽的一部分,并为海槽最南端的一个加里东褶皱带。  相似文献   

4.
秦岭岩群和碧口岩群因构造复杂、化石贫乏,多年来对其层序和时代的意见极不统一。笔者通过地层清理,并结合前人所获得的成果,对这两个岩群的层序和时代进行重新厘定。秦岭岩群包括云母石英片岩、大理岩、片麻岩三套岩石组合,据同位素年龄和区域地层对比定为早元古代;从原秦岭岩群中分解出峡河岩群,据同位素年龄定为中晚元古代。碧口岩群包括变火山岩和变沉积碎屑岩两套岩石组合,据同位素年龄和微古植物化石定为中晚元古代;从原碧口岩群中分解出鱼洞子杂岩,据同位素年龄和硅铁建造定为早元古一太古代。  相似文献   

5.
秦岭岩群和碧口岩群层序时代析重新厘定   总被引:3,自引:0,他引:3  
秦岭岩群和碧口岩群因构造复杂、化石贫乏,多年来对其层序和时代的意见极不统一。笔者通过地层清理,并结合前人所获得的成果,对这两个岩群的层序和时代进行重新厘定。秦岭岩群包括云母石英片岩、大理岩、片麻岩三套岩石组合,据同位素年龄和区域地层对比定为早元古代;从原秦岭岩群中分解出峡河岩群,据同位素年龄定为中晚元古代。碧口岩群包括变火山岩和变沉积碎屑岩两套岩石组合,据同位素年龄和微古植物化石定为中晚元古代;从  相似文献   

6.
海南岛东部黄竹岭地区的原“抱板群”早年已被解体为奥陶纪南碧沟组和中元古代戈枕村组、峨文岭组。本研究在原划归早奥陶世南碧沟组中酸性火山岩夹层中获得锆石SHRIMPU-Pb年龄441±10Ma,属于志留纪兰多维列世,且此火山岩的形成年龄可代表该套火山-沉积岩系的形成时代;在原划归抱板群峨文岭组的变质沉积岩系中获得碎屑锆石LA-ICP-MS U-Pb最小峰值年龄438 Ma,指示其形成于志留纪兰多维列世;原划归抱板群戈枕村组的地质体实为泥盆纪片麻状花岗岩类。因此,本文将黄竹岭地区原“抱板群”重新解体为志留纪地层(保脚村组和蒙花岭组),以及泥盆纪侵入岩类。保脚村组(原峨文岭组)变质沉积岩系及蒙花岭组(原南碧沟组)变质火山-沉积岩系均被泥盆纪花岗岩侵入。海南岛东部黄竹岭地区志留纪兰多维列世地层及泥盆纪侵入岩类的厘定,对海南岛东部地区早古生代地层格架的建立、海南地块构造演化等基础性地质问题的研究具有一定意义。  相似文献   

7.
漠河盆地中生代地层层序及时代   总被引:20,自引:0,他引:20  
依据近几年地层研究成果和野外地质调查获得的新资料 ,对漠河盆地中生代地层进行了厘定 ,将阿杭提河组划归绣峰组 ,木瑞组划归上库力组下部 ,上库力组和依列克得组之间的含煤地层划归上库力组上部。这样纵向上塔木兰沟组—上库力组—依列克得组为火山岩—碎屑岩夹火山岩、煤层—火山岩旋回 ,与邻区具有很好的对比关系。依据新的同位素资料 ,将塔木兰沟组的时代厘定为早白垩世 ;依据双壳类、腹足类、介形类、植物、孢粉等化石资料 ,对漠河盆地额木尔河群的时代进行了讨论 ,认为额木尔河群的时代为晚侏罗世。  相似文献   

8.
舒家坝群(D2-3S)是西秦岭北带构造蚀变岩型金矿重要的赋矿地层,为一套浅变质的具类复理石沉积特征的细碎屑岩及少量碳酸盐岩组合,形成时代为中晚泥盆世。通过1∶5万区域地质调查,在西秦岭两当县北解板沟一带原划舒家坝群中新填绘出一套被断裂围限的火山岩-火山碎屑岩系,与舒家坝群的主体岩性差别明显。通过对该火山岩-火山碎屑岩系进行LA-ICP-MS锆石U-Pb测年,分别获得其中流纹质晶屑凝灰岩加权平均年龄为204±2 Ma,英安斑岩加权平均年龄为209±3 Ma,表明该火山岩-火山碎屑岩系形成于晚三叠世。据此,将其从原划舒家坝群中解体,暂划归华日组(T3hr)。  相似文献   

9.
拉萨却桑地区的原早中三叠世查曲浦组由下部碳酸盐岩和上部火山岩组成,下部碳酸盐岩产丰富的化石,时代为早—中三叠世,上部火山岩无古生物和年代学资料,根据叠置关系作为查曲浦组上部,时代也为早—中三叠世,并且成为该地区经典地层层序而被广泛引用。最近在原查曲浦组上部火山岩段玄武质安山岩中获得248Ma±4Ma的锆石SHRIMP U-Pb年龄,厘定原查曲浦组上部火山岩时代为早三叠世,原查曲浦组存在倒转,火山岩段应位于碳酸盐岩段之下,其下与列龙沟组整合过渡,证明该区二叠系与三叠系是连续沉积的,进一步说明早三叠世该区存在岩浆活动。查曲浦组层序的厘定对探讨冈底斯地区构造演化过程具有重要意义。  相似文献   

10.
东昆仑西段祁漫塔格群的重新厘定   总被引:5,自引:0,他引:5  
通过区域地质调查和研究,认为前人所建立的的祁漫塔格群或滩间山群包括了不同时代的浅变质碎屑岩、中酸性火山岩及基性-超基性岩。根据在东昆仑原划奥陶系祁漫塔格群第一亚群(下部碎屑浊积岩)中采集到早志留世笔石化石组合(这是首次证实东昆仑地区存在志留系地层)及同位素测年资料(鸭子大板火山岩年龄),其时代包含了奥陶纪、志留纪和三叠纪等,根据中国地层指南及中国地层指南说明书和地层清理,对祁漫塔格群进行了解体,将其重新厘定为奥陶纪滩间山群(OT)、志留纪白干湖岩组(Sb)弧后盆地复理石沉积和鸭子泉组(Sy)岛弧火山岩、石炭纪鸭子大坂硅质岩(S i)、三叠纪鄂拉山组(T3e)、蓟县纪狼牙山岩组(Jx l)和南华—奥陶纪阿牙克库木湖蛇绿混杂岩[(N h—O)aΣ]。该成果对于祁漫塔格地区早古生代地层划分对比、构造演化提供了重要新证据。  相似文献   

11.
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   

12.
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.
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.
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   

16.
塘口水电站大坝基础座落在断层和裂隙较发育的龟裂纹灰岩上,岩体完整性差、透水性强,多年运行后,大坝灌浆廊道和排水廊道出现多处集中性漏水,为确保大坝安全和电站正常发电,根据渗漏性质和成因,采用对灌浆廊道补充帷幕灌浆,对排水廊道进行固结+帷幕+回填灌浆。通过灌浆处理后,效果良好,表明灌浆工程有效的将导致坝基渗漏的上下游的裂隙通道封闭,并顺利的经受了随后的汛期洪水考验,大坝安全得到保障。  相似文献   

17.
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.
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.
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.
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   

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