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骆驼山镁铁--超镁铁岩体主要岩石类型有单辉橄长岩、橄榄辉长苏长岩、橄长岩、辉长苏长岩、辉长岩。橄榄石Fo为76~83,为贵橄榄石。辉石化学特征以及主量元素特征表明其属拉斑玄武岩系列,稀土元素配分曲线总体表现为轻稀土稍富集、重稀土微分异的特征。微量元素具有大离子亲石元素(Rb、Ba、Sr)相对富集,高场强元素Ta、Hf、Th相对亏损的特征。岩浆演化过程中分离结晶作用主要受单斜辉石控制。Nb/U、Ce/Pb值更接近于地壳值以及敏感元素比值协变关系表明岩浆演化过程发生了同化混染作用。Th/Yb-Nb/Yb、La/Ba-La/Nb之间的关系指示岩浆源区可能为流体交代改造的富集型岩石圈地幔。 相似文献
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《四川地质学报》2019,(4)
对四川盆地西南缘雷波-永善地区志留系龙马溪组黑色页岩的主量元素和稀土元素地球化学特征进行研究,并探讨其地质意义。结果表明,研究区龙马溪组地层的(La/Yb)、(Ce/Yb)_N和∑~(LR EE)/∑~(HREE)、值指示稀土元素明显分异,呈现轻稀土元素富集,重稀土元素亏损特征;同时也反映沉积期沉积速率较慢。沉积期构造背景指标MnO/TiO_2∑~(LR EE)/∑~(HREE)(0.5),δCe平均值(0.86～0.97);沉积期盐度指标CaO/(CaO+Fe)(0.2),m值(16.37～47.42);沉积期氧化还原指标δEN正异常、Ce负异常、Ceanom正异常、V/Cr值多在2左右和下段Ni/Co值大于5指示研究区为大陆边缘具稳定还原性的中、高盐度海水环境。根据SiO_2-K_2O/Na_2O物源区构造背景判别图上的投点分布特征与主量元素在Roser泥岩区判别方程图中的特征,判定龙马溪组页岩母质主要为扬子克拉通东南活动大陆边缘中性火山物质以及康滇古陆和黔中隆起的成熟大陆石英物质。 相似文献
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位于北淮阳东段的板桥岩体为凌家冲杂岩体的重要组成部分,岩石类型为花岗闪长岩。该岩体偏铝质、富碱、高钾、贫钙,属于高钾钙碱性系列岩石;稀土元素含量中等,(La/Yb)N与HREE/LREE值较高,重稀土元素相对亏损,铕弱负异常,属轻稀土元素富集型;大离子亲石元素Rb、Ba、K、La、Nd富集,高场强元素Nb、Ta、Ti、P亏损。通过LA-ICP-MS锆石U-Pb定年,获得板桥岩体~(206)Pb/~(238) U年龄为129.0±1.9Ma,表明该岩体形成于燕山晚期,是早白垩世岩浆活动的产物。板桥花岗闪长岩形成于后碰撞的伸展构造环境。 相似文献
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贵州务正道地区铝土矿床稀土元素组成及地质意义 总被引：2，自引：0，他引：2
稀土元素(REE)是一组具有相同地球化学性质和特殊地球化学属性的指示性元素。务正道地区主要矿床稀土元素组成显示出,矿层和下伏志留系韩家店组地层稀土元素总量、配分模式基本一致,相关性较好,揭示铝土矿成矿物源与下伏志留系韩家店组有成因联系;矿层和韩家店组LREE/HREE均大于1,轻稀土富集较强烈,而重稀土不同程度亏损;(La/Ce)N平均0.87,总体较低;δCe平均1.22,为弱-中等比值,表明铝土矿物源主要来自陆源,沉积环境主要为陆相沉积,局部为海相沉积;主要层位(La/Sm)N>(Gd/Yb)N,说明轻重稀土元素分异较好;稀土元素富集对岩性有选择性,在矿层及富含绿泥岩、粉砂质页岩的志留系韩家店组地层中强烈富集,在石炭系黄龙组白云质灰岩及二叠系栖霞组灰岩中贫化。 相似文献
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《地质通报》2019,(Z1)
内蒙古乌拉特中旗中蒙边境地区的扎嘎乌苏岩体主要由闪长岩、石英闪长岩、花岗闪长岩和黑云母二长花岗岩组成,岩体及围岩普遍发育面理南倾的糜棱岩带。通过LA-ICP-MS锆石U-Pb测年,获得扎嘎乌苏岩体中黑云母二长花岗岩的结晶年龄为450.3±3.7Ma(MSWD=2.8),表明扎嘎乌苏岩体的形成时代为晚奥陶世。扎嘎乌苏岩体中不同类型岩石全岩微量和稀土元素组成总体相似,均呈现轻稀土元素相对于重稀土元素强烈富集,大离子亲石元素Ba、Sr等富集,高场强元素Nb、Ta、Ti相对亏损,高Sr,低Y、Yb,高Sr/Y、La/Yb值等特征,具有埃达克岩和岛弧岩浆岩的地球化学特征。这些新的年代学和岩石地球化学数据,为索伦山地区晚奥陶世古亚洲洋俯冲消减提供了可靠的证据。 相似文献
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沉积岩的微量元素和稀土元素蕴含了大量的地质信息,对研究物源区性质与沉积环境的重塑具有重要的指导意义。本文研究了渤海湾盆地东濮凹陷古近系沙河街组沙三段泥岩和盐岩的微量元素及稀土元素的地球化学特征。结果表明:微量元素Sr、Ba丰度高,其他Rb、V、Ni、Mn、Fe、Cr、Br等元素含量较低,多数微量元素含量比同类岩石克拉克值偏高;∑REE为47.1×10-6～268.02×10-6,平均值为181.55×10-6,接近于后太古宙页岩(PAAS)的平均值,高于大陆上地壳(UCC)平均值。轻稀土与重稀土总量的比值为7.96～11.46,平均值为9.71,其分配模式表现为轻稀土富集,重稀土相对亏损,整体特征为"右倾斜型",但重稀土元素为较平坦。铕(Eu)具有明显的亏损(0.48～0.70),铈(Ce)轻微亏损(0.89～0.97)。而盐岩样品中所含微量元素和稀土元素含量普遍很少。通过对样品中Sr/Cu、V/(V﹢Ni)、(La/Yb)N、Sr/Ba、δCe和Ceanom等特征参数的分析,总结出沙三段属于陆相沉积,处于还原、厌氧、咸水沉积环境;根据La/Th-Hf和Co/Th-La/Sc源岩判别图解、Eu、δEu以及REE—La/Yb等组合特点,显示源岩主要为中酸性长英质岩石(花岗岩)和混合长英质岩/基性岩,古老沉积岩对其贡献不大,主要来自内黄隆起和鲁西隆起的碎屑物质。 相似文献
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研究区位于巴音戈壁盆地因格井坳陷北端,通过该区巴音戈壁组上段粘土岩8个样品的稀土元素地球化学特征分析表明,该地区样品稀土元素总量(ΣREE)偏低,LREE/HREE的值、(La/Yb)N的值及REE配分模式均为轻稀土元素富集,重稀土元素相对亏损,表现为右倾,存在Eu的负异常,Ce元素处全部为基本正常或微量负异常。样品的(Ceanom)指数值总体反映了沉积时期水体的缺氧还原环境。(La/Yb)N的值间反映了长而缓慢的沉积,可推测水深较深,可能为湖湘沉积。物源分析结果反映巴音戈壁组上段粘土岩原始物质应来自上地壳,来自于活动大陆边缘和大陆岛弧环境的长英质物源。 相似文献
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刘村岩体岩石类型主要为中细粒似斑状二长花岗岩,部分为粗中粒二长花岗岩,两者呈渐变过渡关系。具准铝质-弱过铝质的高钾钙碱性系列岩石特征。其LREE/HREE、La N/Yb N值较大,显示其轻重稀土分馏明显,富集轻稀土、亏损重稀土。岩石总体具有大离子亲石元素(LILE)Rb、Th富集,Sr、Ba亏损,高场强元素(HFSE)U、La、Ce、Nd、Hf、Zr富集,Nb、Ta、Ti亏损,岩体整体亏损HFSE,富集LILE。通过LA-ICP-MS锆石U-Pb定年,获得刘村岩体206Pb/238U年龄为123.2±2.2 Ma,属早白垩世岩浆活动产物,代表刘村岩体的成岩年龄。刘村岩体富集—强富集的元素有W、Mo、Zn、As、Sb、Hg、Cu、Au等,表明该岩体是铜及多金属富集成矿的有利地段。 相似文献
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内蒙古自治区西部阿拉善右旗吊井子一带发育有3处镁铁质—超镁铁质岩体,位于华北板块之巴丹吉林坳陷西缘,其主要岩石类型为角闪石岩及橄榄岩。相对比与北大山镁铁质—超镁铁质岩体,本文研究区内角闪石岩分异明显,具有低钾、高钛、高铝、低磷等特征;大离子亲石元素富集,高场强元素亏损,稀土元素分异不明显,La/Sm、La/Ce、La/Yb较低,为亏损地幔来源的(N-MORB)洋中脊玄武岩的特点;橄榄岩富镁贫铁,具有镁质超基性岩的特点,岩浆未发生明显分异,微量元素中Cu、Ni、Co、Cr、V等地幔来源的元素强烈富集,不相容元素富集,稀土元素分异明显,稀土曲线右倾,具有弱Eu异常,La/Sm、La/Ce、La/Yb值较高,岩浆源于富集地幔物质的部分熔融。两种岩石地球化学成分及特征差异较大,不具备同源性特征。 相似文献
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本文主要叙述了在煤田地质钻探中泥浆的应用,粘土和各种试剂的选择以及在野外通过实验的方式来进行泥浆组分的配比,描述了调节泥浆性能的正确方法。本文还阐述了在煤田钻探中出现的浆液漏失现象,和用水泥堵漏的方法。 相似文献
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In order to identify the mud diapirs and mud volcanoes off SW Taiwan, we have examined ∼1500 km long MCS profiles and related marine geophysical data. Our results show ten quasi-linear mud diapirs, oriented NNE–SSW to N–S directions. Thirteen mud volcanoes are identified from the multibeam bathymetric data. These mud volcanoes generally occur on tops of the diapiric structures. Moreover, the active mud flow tracks out of mud volcanoes MV1, MV3 and MV6 are observed through the high backscatter intensity stripes on the sidescan sonar images. The heights of the cone-shaped mud volcanoes range from 65 m to 345 m, and the diameters at base from 680 m to 4100 m. These mud volcanoes have abrupt slopes between 5.3° and 13.6°, implying the mudflow is active and highly viscous. In contrast, the flat crests of mud volcanoes are due to relative lower-viscosity flows. The larger cone-shaped mud volcanoes located at deeper water depths could be related to a longer eruption history. The formation of mud diapirs and volcanoes in the study area are ascribed to the overpressure in sedimentary layers, compressional tectonic forces and gas-bearing fluids. Especially, the gas-bearing fluid plays an important role in enhancing the intrusion after the diapirism as a large amount of gas expulsions is observed. The morphology of the upper Kaoping Slope is mainly controlled by mud diapiric intrusions. 相似文献
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The mud volcanoes of Pakistan 总被引：1，自引：0，他引：1
Marine-geologic investigations on the Arabian Sea by Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) in 1995 and 1998, and land expeditions in 1998 and 1999 to the coastal regions of the Makran Desert/Pakistan have extended the knowledge of the aerial distribution of mud volcanoes. These structures rise from under-compacted formations within the regional accretionary prism, which is built by the subduction of the oceanic crust of the Arabian Sea and its km-thick sedimentary load. The occurrence of mud volcanoes is limited to the abyssal plain near the accretionary front, to the coastal region of the Makran Desert and to a region in the interior of the Desert to the south to southeast of the so-called Hinglay Synform. The location of mud volcanoes in Pakistan is clearly tied to fault systems. Mud volcanoes are conspicuously absent on the lower slope of the accretionary prism, where thick gas hydrate layers have developed. The presence of large gas plumes emerging from the seafloor landward of the gas hydrate stability zone at water depths of less than 800 m points to a redirection of fluids from depth, which might explain the absence of mud volcanoes along the lower slope. 相似文献
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针对武汉地区不同地层、不同工艺产生的建筑工程废弃泥浆,通过光谱仪分析了其主要化学成分,并通过过滤、真空抽滤、离心以及不同絮凝剂的正交试验,以上清液浊度和清液率为主要指标对废弃泥浆泥水分离效果进行评价。试验发现：废弃泥浆固相颗粒以有机质为主;采用过滤方式取得的清液浊度较低,但清液率较少;采用真空抽滤方式处理废弃泥浆可以获得较多的上清液;采用离心方式能处理除含特细颗粒外的多数废弃泥浆;正交试验表明阳离子絮凝剂（PAM）处理废弃泥浆效果较好。 相似文献
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渗漏污染是建干岩溶地区赤泥堆场的主要环境工程地质问题。解决这一问题的关键是通过查明地下水的渗流特性，从而确定其渗漏通道。试验研究表明，堆场内各水点之间、堆场与外部各水点存在一定的水力联系，其流速受季节影响，在枯水期较为缓慢；地下水流向主要取决于地下暗河的走向；堆场区地下水流向总体是自堆场向北流向右江，局部地下水的流向受构造和岩溶裂隙控制；岩溶管道是渗流的主要通道。因此，存在因赤泥渗流污染居民生产与生活水源地的可能，污染物的扩散途径主要是岩溶通道。 相似文献
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火山、泥火山/泥底辟及含气陷阱这些特殊的地质体,不仅是揭示地球深部构造运动的窗口和地球深部流体活动特点的表征,而且其与油气运聚关系密切,具有非常重要的油气地质意义。火山与泥火山/泥底辟的主要差异及区别是所形成的物质基础及源动力不同,前者主要反映地壳深部地球动力学过程,其物资基础来源于火山幔源活动上侵和喷发的岩浆物资;后者则是在结晶基底以上的沉积盆地中,由快速沉积充填的欠压实泥页岩发生塑性流动而产生底辟上拱所形成的产物,其物质基础为巨厚欠压实泥页岩。含气陷阱则为气侵或富含气地层所形成的地震反射畸变之痕迹。火山、泥火山/泥底辟发育演化及展布与油气运聚成藏存在明显的成因联系和耦合关系,且控制和制约了沉积盆地中油气分布与聚集。 相似文献
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LAWRENCE A. AMY PETER J. TALLING VICTORIA O. EDMONDS ESTHER J. SUMNER ANNE LESUEUR 《Sedimentology》2006,53(6):1411-1434
The settling behaviour of particulate suspensions and their deposits has been documented using a series of settling tube experiments. Suspensions comprised saline solution and noncohesive glass‐ballotini sand of particle size 35·5 μm < d < 250 μm and volume fractions, φs, up to 0·6 and cohesive kaolinite clay of particle size d < 35·5 μm and volume fractions, φm, up to 0·15. Five texturally distinct deposits were found, associated with different settling regimes: (I) clean, graded sand beds produced by incremental deposition under unhindered or hindered settling conditions; (II) partially graded, clean sand beds with an ungraded base and a graded top, produced by incremental deposition under hindered settling conditions; (III) graded muddy sands produced by compaction with significant particle sorting by elutriation; (IV) ungraded clean sand produced by compaction and (V) ungraded muddy sand produced by compaction. A transition from particle size segregation (regime I) to suppressed size segregation (regime II or III) to virtually no size segregation (IV or V) occurred as sediment concentration was increased. In noncohesive particulate suspensions, segregation was initially suppressed at φs ～ 0·2 and entirely inhibited at φs ≥ 0·6. In noncohesive and cohesive mixtures with low sand concentrations (φs < 0·2), particle segregation was initially suppressed at φm ～ 0·07 and entirely suppressed at φm ≥ 0·13. The experimental results have a number of implications for the depositional dynamics of submarine sediment gravity flows and other particulate flows that carry sand and mud; because the influence of moving flow is ignored in these experiments, the results will only be applicable to flows in which settling processes, in the depositional boundary, dominate over shear‐flow processes, as might be the case for rapidly decelerating currents with high suspended load fallout rates. The ‘abrupt’ change in settling regimes between regime I and V, over a relatively small change in mud concentration (<5% by volume), favours the development of either mud‐poor, graded sandy deposits or mud‐rich, ungraded sandy deposits. This may explain the bimodality in sediment texture (clean ‘turbidite’ or muddy ‘debrite’ sand or sandstone) found in some turbidite systems. Furthermore, it supports the notion that distal ‘linked’ debrites could form because of a relatively small increase in the mud concentration of turbidity currents, perhaps associated with erosion of a muddy sea floor. Ungraded, clean sand deposits were formed by noncohesive suspensions with concentrations 0·2 ≤ φs ≤ 0·4. Hydrodynamic sorting is interpreted as being suppressed in this case by relatively high bed aggradation rates which could also occur in association with sustained, stratified turbidity currents or noncohesive debris flows with relatively high near‐bed sediment concentrations. 相似文献