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1.
山东龙口市大磨曲家金矿区位于沂沭断裂带东侧,招平成矿带北端,玲珑金矿田东风矿床北东段。区内控矿赋矿构造为NE向断裂带及派生、伴生次级断裂,两组或多组断裂构造的叠加交汇处是金成矿的最有利部位。石英脉型或蚀变岩型金矿床在含矿带上出现次级高阻的石英脉或者次级高阻的硅化带及绢英岩化带,而次级高阻、高极化率局部异常是该区矿脉异常的基本特征。通过对该区地质暨地球物理、地球化学特征的分析,建立了找矿标志。  相似文献   

2.
The distribution of methyl-2-methyl-2-(4,8,12-trimethyltridecyl)chromans (M - MTTC) is related to sedimentary environments. 5,7,8 - tri-Me-MTTC, 5,8 -di - Me-MTTC and 7,8 - di - Me - MTTC have been found in coal for the first time, implying that M-MTTC is widely spread in sediments.The distribution of M - MTTC. the presence of C32—C35 benzohopanes, high Pr/Ph ratio, obvious even - odd predominance in C24—C34 alkanes and odd-even predominance in normal alkanes provide strong evidence of a near - shore lacustrine environment.  相似文献   

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4.
湖泊沉积物中沉积韵律是个普遍现象,但盐类矿物组成的韵律现象比较少见。盐类矿物多出现在干旱的环境中,芒硝是干冷环境下沉积的盐类矿物。本文主要根据芒硝层厚度的变化,结合原生硼砂、粘土、孢粉、碳酸盐等环境指标,讨论了秋里南木湖27.8~4.97 ka BP的气候环境演化并进行了区域对比,为青藏高原是气候变化敏感区的观点提供了盐类矿物学方面的证据。研究认为,27.8~20.5 ka BP湖区气候相对温暖潮湿,20.5~11.4 ka BP气候寒冷,其中20.5~17.5 ka BP气候极端干冷,为末次盛冰期在秋里南木湖的反映,17.5~17.1 ka BP、15.9~15.2 ka BP和14.1~13.4 ka BP气候条件略微好转;11.4~10.1ka BP气候温暖,10.1~7.5 ka BP气候寒冷,其中8.1~7.9 ka BP的冷气候为“8.2 ka BP冷事件”的反映;7.5~4.97 ka BP气候相对温暖,但波动频繁。原生硼砂的存在说明,27.8 ka以来秋里南木湖水温度不高,湖水较浅,水动力条件稳定。  相似文献   

5.
郭文献  李越  张陵  赵荣生  王鸿翔 《水文》2019,39(6):69-73
根据长江中游宜昌站1952~2015年长时间序列径流泥沙资料,运用Mann-Kendall趋势检验法、小波分析法和均值差异T检验等方法,揭示宜昌站径流泥沙的演变规律及其驱动因素。结果表明:(1)径流量无显著下降趋势,而输沙量下降趋势明显;(2)径流量在2005年发生突变,输沙量在2002年发生突变;(3)通过小波分析发现年径流量和年输沙量存在以20~24a为主周期的变化规律;(4)年径流量可分为1952~1955,1961~1968,1979~2001年3个多水期和1956~1960,1969~1978,2002~2015年3个少水期,输沙量可分为1952~1993,1998~2002年2个多沙期和1994~1997,2003~2015年2个少沙期;(5)年输沙量显著减少主要为水库拦沙、河道采砂和水土保持工程等人类活动所致。  相似文献   

6.
湖相碳酸盐岩是一种分布极其广泛的陆相碳酸盐岩。中国湖相碳酸盐岩沉积始于二叠纪—三叠纪,经侏罗纪—白垩纪发展,鼎盛于古近纪,具有沉积时间跨度长、分布面积广的特征。碳酸盐岩发育方式多样,常以多个单层、薄夹层状、互层状、韵律沉积为主,也见以结核状或钙质微体化石等薄层赋存于泥岩、页岩等细粒碎屑岩中。湖相碳酸盐岩δ13C值介于-10.0×10-3~+10.0×10-3之间,多数为-5.0×10-3~+5.0×10-3,正负值均有。二叠系—三叠系δ13C发生负偏,侏罗系—白垩系先正向漂移随后负偏,古近系—新近系再次正偏,达最大值约+5.0×10-3。氧同位素δ18O值介于-20.0×10-3~+2.0×10-3之间,多数为-15.0×10-3~-0.0×10-3,几乎全部为负值。二叠系—三叠系、侏罗系—白垩系碳酸盐岩δ18O值在-15.0×10-3~-3.0×10-3之间变化,古近系—新近系δ18O值明显正偏移,多数位于-10.0×10-3~0.0×10-3。中国湖相碳酸盐岩碳氧同位素相关性分析表明,δ13C与δ18O密切相关,且δ13C值多正值或轻微负值,指示湖泊为封闭型咸水—半咸水环境;δ13C和δ18O不相关,δ13C值为负值,指示湖泊为开放型淡水环境。  相似文献   

7.
该文介绍了对高压天然气管道采用直接监测点与间接监测点相结合的沉降监测方法。分析了间接监测点代替直接监测点进行管道监测的可行性;并对直接监测点与附近水准点沉降关系,即管道沉降与地层沉降之间的关系进行了初步的探讨,对过去经验地认为管道在敷设后一年后即达到稳定沉降与地层一起沉降的观点提出了质疑。  相似文献   

8.
青藏高原及邻区三阶段构造演化与成矿演化   总被引:10,自引:0,他引:10  
李德威 《地球科学》2008,33(6):723-742
青藏高原具有典型的三分时空结构和3种尺度动力学体系.青藏高原由3个构造结调整的3个盆山体系组成, 北部、东部和南部3个盆山体系分别受控于古亚洲洋及西伯利亚、西太平洋和特提斯三大构造域, 经历了前寒武纪超大洋一超大陆耦合、加里东期-印支期-燕山期和喜马拉雅早期自北而南的洋陆耦合和板内盆山耦合三大构造发展过程, 形成于地核流层驱动的地核(或全球) 动力学过程、地幔流层驱动的地幔(或岩石圈) 动力学过程和地壳流层驱动的地壳(或大陆) 动力学过程, 构成历史地球系统动力学系统.青藏高原不是印度板块与欧亚板块碰撞的结果, 而是形成于下地壳流动驱动的板内盆山作用, 可分为以中、新生代有序向南迁移式构造隆升、水平运动、地质作用和成矿作用为特征的板内造山阶段和以脉动式快速隆升、垂直运动、地理作用和环境变化为特征的均衡成山阶段.构造谱系决定了成矿谱系, 区域构造叠加演化造成地壳成熟度的不断增加和矿床密集度的不断提高.青藏高原3个构造成矿演化阶段包括1.8~1.4Ga、500~420Ma、300~260Ma、180~120Ma、65~30Ma、23~7Ma等6个主金属成矿期, 1.8~1.4Ga超大陆裂解事件形成与深地幔火山岩浆作用有关的大红山式海相火山喷流沉积改造型铁铜矿、金川式与镁铁-超镁铁质岩有关的铜镍硫化物浆矿床, 500~420Ma、300~260Ma和180~120Ma特提斯裂解环境下形成罗布莎式地幔剪切-改造脉型(豆荚状) 铬铁矿床、呷村式海相火山成因块状硫化物矿床等, 180~120Ma、65~30Ma和23~7Ma是青藏高原自北而南板内伸展环境下大规模成矿期, 形成驱龙式斑岩铜矿床、哀牢山式剪切带型金矿床、金顶式陆相盆地沉积型铅锌矿床, 构成一个完整的地球系统成矿动力学演化体系.   相似文献   

9.
Preparation and Characterization of Hydroxyiron-Montmorillonite Complexes   总被引:1,自引:0,他引:1  
Iron elementin soil exists mainly in form s of Fe(OH) 2 ,Fe(OH ) 2 and Fe2 (OH ) 2 2 in tropical and subtropical areaswhere p H values are less than7.These hydroxy- Fe ions reactslowly with montmorillonite by intercalation into their inter-layer space and adsorption on their surfaces,and in this wayvarious hydroxyiron- montmorillonite complexes are formed(Cool and Vansant,1998;Wu et al.,1997;Molinared andClearfield,1994) . Hydroxyiron- montm orillonite complexesare assum ed to have…  相似文献   

10.
河南省大青地区沿乔端-瓦穴子断裂带和二郎坪群火神庙组分布着以银、铅、锌为主的带状异常,过去未引起重视。通过地质大调查项目实施,对本区地球化学特征进行了研究,并重点检查了以银、铅、锌为主的异常。在火神庙组的变石英角斑岩中发现了银、铅、锌多金属矿化带,伴生有金、铜等金属矿化,并对其成因进行了初步分析。鉴于区域上存在众多的以银、铅、锌为主的综合异常和相似的地质环境,找矿产潜力很大,随着矿产资源评价工作的全面展开,本区找矿定会有较大的发现和突破。  相似文献   

11.
深层油气勘探是未来油气资源的重要接替领域。渤海湾盆地下伏石炭-二叠系煤系烃源岩自油气勘探取得新突破以来,一直是深层油气领域研究的热点。黄骅坳陷新部署的QG8井奥陶系碳酸盐岩储层和YG1井二叠系砂岩储层获高产凝析油气流,其来源判别问题是深层油气勘探的关键。针对QG8、YG1井凝析油气开展的生物标志化合物、有机碳稳定同位素和原油物性研究表明:两口井的凝析油均为低黏度、低密度的典型轻质原油,具有姥鲛烷优势(Pr/Ph>2.8),QG8井凝析油饱和烃δ13C为-29.1‰、芳烃δ13C为-26.8‰;天然气δ13C1偏重,介于-39.7‰~-36.4‰之间,干燥系数大于0.8,重烃可达16.2%,为偏干湿气。QG8与YG1井凝析油特征与黄骅坳陷石炭-二叠系煤系烃源岩(饱和烃δ13C为-29.26‰~-26.87‰,芳烃δ13C为-26.62‰~-24.15‰)及KG4井原油物性(0.757 1~0.840 2 g/cm3)相近,天然气特征则相似于济阳坳陷GBG1井的煤成气(δ13C1为-43‰~-35‰),表明高产的凝析油气来自石炭-二叠系煤系烃源岩。证实渤海湾盆地深层石炭-二叠系煤系具有生烃潜力和油气勘探前景。  相似文献   

12.
道郎呼都格钾长花岗岩体位于华北克拉通北缘白乃庙构造带。SHRIMP锆石U-Pb定年获得139.6±1.7Ma岩体侵位年龄。岩体富硅(SiO2=75.79%~78.07%)、富碱(K2O+Na2O=7.39%~8.29%)、贫钙(CaO=0.22%~0.59%);稀土配分曲线呈现"海鸥式"分布特征,显示强烈的Eu负异常(δEu =0.03~0.12);微量元素特征显示具有较高Ga(21.2×10-6~26.6×10-6)、Zr(173×10-6~417×10-6)、Nb(32.3×10-6~42.4×10-6)和Y(24.6×10-6~53.9×10-6)含量,较低的Sr(14×10-6~44×10-6)、Ba(18×10-6~211×10-6)含量,在微量元素原始地幔标准化蛛网图上显示明显的Ba、Sr、P、Eu和Ti的负异常。以上特征表明道郎呼都格钾长花岗岩为A型花岗岩,为高温低压下长英质地壳的部分熔融及其后长石、榍石等的分离结晶作用的产物。结合区域构造演化,本文认为该区钾长花岗岩形成于板内伸展背景。在晚中生代期间,华北板块北缘的构造体制经历了重要的转变,由挤压体制转变为岩石圈减薄和地壳伸展,在伸展体制下,软流圈地幔上涌对上覆长英质地壳的直接加热作用促使其部分熔融形成该区A型花岗岩。  相似文献   

13.
Abstract: The glass and mineral chemistry of basalts examined from the northern central Indian ridge (NCIR) provides an insight into magma genesis around the vicinity of two transform faults: Vityaz (VT) and Vema (VM). The studied mid-ocean ridge basalts (MORBs) from the outer ridge flank (VT area) and a near-ridge seamount (VM area) reveal that they are moderately phyric plagioclase basalts composed of plagioclase (phenocryst [An60–90] and groundmass [An35–79]), olivine (Fo81–88), diopside (Wo45–51, En25–37, Fs14–24), and titanomagnetite (FeOt ~63.75 wt% and TiO2 ~22.69 wt%). The whole-rock composition of these basalts has similar Mg# [mole Mg/mole(Mg+Fe2+)] (VT basalt: ~0.56–0.58; VM basalt: ~0.57), but differ in their total alkali content (VT basalt: ~2.65; VM basalt: ~3.24). The bulk composition of the magma was gradually depleted in MgO and enriched in FeOt, TiO2, P2O5, and Na2O with progressive fractionation, the basalts were gradually enriched in Y and Zr and depleted in Ni and Cr. In addition, the SREE of magma also increased with fractionation, without any change in the (La/Yb)N value. Glass from the VM seamount shows more fractionated characters (Mg#: 0.56–0.57) compared to the outer ridge flank lava of the VT area (Mg#: 0.63–0.65). This study concludes that present basalts experienced low-pressure crystallization at a relatively shallow depth. The geochemical changes in the NCIR magmas resulted from fractional crystallization at a shallow depth. As a consequence, spinel was the first mineral to crystallize at a pressure >10 kbar, followed by Fe-rich olivine at <10 kbar pressure.  相似文献   

14.
黔东北地区钒矿成矿地质特征及成矿预测   总被引:1,自引:0,他引:1  
黔东北地区沉积型钒矿与寒武系下统九门冲组(1jm)黑色岩系密切相关。本文通过对该区钒矿产出的区域地质背景、含矿岩系、赋矿岩石地化特征,岩相古地理环境、矿床时空分布和矿体产出特征等进行综合分析,表明该区具有很好的成矿地质条件。根据本区找矿实践和成矿相关理论、控矿因素等综合研究,圈定了松桃石梁—孟溪、松桃盘石—江口桃映—坝黄、印江永义、铜仁漾头—万山黄道、石阡坪山—聚凤5个成矿有利远景区,为指导今后在该区开展钒矿找矿工作,取得更大的找矿突破提供参考。  相似文献   

15.
北黄海盆地X1和X2钻井岩心揭示上侏罗统中有侵入的花岗质岩石,镜下鉴定其为花岗斑岩。对花岗斑岩进行了主量、微量和稀土元素测试分析,样品的Si O2含量介于70.22%~71.88%之间,K2O/Na2O比值介于0.95~1.68之间,A/CNK比值介于0.75~1.12之间,有高钾钙碱性、弱碱质-偏铝质性质。微量元素组成富集Rb、Th、U等元素,相对亏损Nb、Eu、Sr等元素。稀土总量较高(∑REE=50.38×10-6~162.27×10-6),轻稀土(LREE)相对富集(LREE/HREE=6.86~25.43,(La/Yb)N=10.06~57.76),具有明显的Eu负异常(?Eu=0.65~0.83)。样品的Th含量高,与Rb呈正相关性,综合主量元素特征(A/CNK1.1),判别其为I型花岗岩。LA-ICP-MS锆石U-Pb测年结果表明X1井花岗斑岩年龄为110±1 Ma,X2井花岗斑岩年龄108±1 Ma、107±1 Ma,形成于早白垩世晚期。结合区域构造背景及岩石地球化学特征认为,北黄海盆地花岗斑岩形成于板块碰撞后的伸展构造背景。  相似文献   

16.
西藏冈底斯带花岗岩的时空分布特征及地壳生长演化信息   总被引:159,自引:1,他引:158  
花岗岩是大陆特有的重要组成部分,同时与矿产资源有密切的关系。西藏花岗岩约占西藏自治区面积的12%,其中,80%分布在冈底斯岩浆岩带。在空间上,冈底斯花岗岩带大致可以分为3个亚带:北带、中带和南带;在时间上,以印度一亚洲大陆碰撞事件为标尺,可将青藏高原构造一岩浆事件划分为碰撞前(〉65Ma)、碰撞期(65~45Ma)、后碰撞(〈45Ma)3大阶段。在这3个阶段中,冈底斯带都产生了具有各自特点的花岗岩构造一岩浆类型。冈底斯花岗岩类的形成演化与新特提斯班公湖一怒江洋及雅鲁藏布洋的形成演化,有密切的关系。因此,其岩石的Nd,Sr同位素资料,对地壳生长与演化有重要的指示意义。冈底斯南带的大部分地区的花岗岩,均具有εNd(t)(+)值(+1.64~+5.21),模式年龄tDM也很年青(〈500Ma),具有初生(juvenile)地壳的特征。在花岗岩成因中地幔物质有重要的贡献。而冈底斯中带、北带及南带西段的花岗岩类以εNd(t)(-)值为特征(-5.3~-17.3),模式年龄tDM有两组值1.2Ga及2.0~2.5Ga,暗示这些地区的地壳具有古元古代一中元古代基底在花岗岩成因中,地壳组分具有主要贡献。  相似文献   

17.
G. B. Fershtater 《Petrology》2013,21(2):181-202
The paper reports major evolutionary trends of Paleozoic magmatism in the Urals in relation to the closure of the oceanic basin and associated subduction, obduction, and collision. An attempt is undertaken to use these data as a basis for reproducing the geodynamic and thermal regime during various stages of the regional geological evolution. Distinctive compositional features of the rocks, the discrete character of magmatism reflecting changes in the geodynamic environments, and the transition from predominantly mantle sources of magmatism (at 460-380 Ma) to mantle-crustal (at 360-310 Ma) and finally crustal (290-250 Ma) ones, alternating epochs of relatively “dry” and “hydrous” mantle magmatism at 460-430 Ma and the “hydrous” type of later magmatism make it possible to reproduce the thermal regime of the orogen. During the intense low-hydrous basite magmatism (460-430 Ma), the temperature in the magma generation region was 1300-1100°C and decreased to 1100-900°C during predominantly hydrous magmatism (425-400 Ma). The P-T parameters of hydrous anatexis (360-310 Ma) that gave rise to tonalites and granodiorites were 7-9 kbar and 800 ± 50°C; they constrain the maximum temperature in the lower crust. The next stage of the hydrous anatexis of tonalites and granodiorites resulted in intense granite-forming processes (290-250 Ma) and occurred at pressures close to 5-6 kbar and temperatures of 700 ± 50°C. In the situation of the adiabatic heat transfer with fluids, the minimum temperatures in the upper mantle in the Ural suprasubduction epioceanic mobile belt at a depth of approximately 80 km can be provisionally estimated as follows: 1300 ± 100°C at 450-425 Ma, 1100 =- 100°C at 425-400 Ma, and 900 ± 100°C at 375-250 Ma. Data reported in the paper testify that the temperature in the upper mantle and crust of the Ural Mobile Belt was 150-200°C lower than in neighboring oceanic and continental areas, and this places the Urals among orogens of the “cold” type (Maruyama et al.,2007).  相似文献   

18.
广西大厂锡多金属矿床是世界上最大的锡多金属矿床之一,区内花岗斑岩主要分布于铜坑-长坡-巴里-龙头山矿区的东侧,受近SN向张扭性断裂构造控制,并对早期形成的矿体产生了叠加改造作用.为了探讨花岗斑岩的成岩成矿条件,对花岗斑岩中以斑晶、包体以及基质形式产出的黑云母进行了详细的电子探针分析.结果显示:花岗斑岩中的黑云母主要为岩浆成因的铁质黑云母,且指示岩体具有高碱度的特征.与斑晶和包体黑云母相比,基质黑云母相对富铁、锰、锂,贫镁、钛.斑晶和包体黑云母结晶温度为688~715℃,结晶压力为1.7~2.3 kbar,相当于6.3~8.4 km的侵位深度;基质黑云母的结晶温度为630~673℃,结晶压力为1.6~2.0 kbar,相当于6.0~7.4 km的侵位深度.斑晶、包体和基质黑云母的氧逸度分别为-17.0~-16.1、-17.0~-16.6和-19.0~-17.4,指示在侵位的过程中,伴随着岩浆的上涌,氧逸度随之降低,成岩条件由相对氧化向相对还原的方向变化.与花岗斑岩有关的共存流体性质研究显示,斑晶黑云母中的lg(fH2O/fHF)Fluid、lg(fH2O/fHCl)Fluid和lg(fHF/fHCl)Fluid值分别为3.41~3.82、3.78~4.07和-0.54~-0.17;包体黑云母中的lg(fH2O/fHF)Fluid、lg(fH2O/fHCl)Fluid和lg(fHF/fHCl)Fluid值分别为3.90~4.11、3.86~4.11和-0.74~-0.43;基质黑云母中的lg(fH2O/fHF)Fluid、lg(fH2O/fHCl)Fluid和lg(fHF/fHCl)Fluid值分别为3.90~4.39、3.85~4.96和-0.61~0.25.结果显示,在花岗斑岩上侵的过程中,与不同阶段结晶生成的斑晶、包体和基质黑云母共存的流体在成分上有一定的差异性,不是单一的流体.大厂花岗斑岩中黑云母成分的变化指示岩浆结晶过程早期阶段具有高温、高碱度和低氧逸度的特征,有利Sn元素的活化、迁移、富集,进而对大厂锡多金属矿床起到叠加改造作用.   相似文献   

19.
There are four units of high-pressure to ultrahigh-pressure metamorphism extending from south to north across the Tongbai-Dabie Mountains: the epidote-blueschist-facies unit, the low-temperature eclogite facies unit , the ultrahigh-pressure eclngite facies unit and the medium-temperature eclogite facies unit . The later two units were formed during the Caledonian subduction between the Tongbai-Dabie microplate and the North China plate ,the former two units are the products of Indosinian continental-continental subduction and collision between the Yangtze and the North China plates.  相似文献   

20.
In order to meet the needs of geochemical mapping and geochemical exploration, 125 geochemical reference materials have been successively prepared by the Institute of Geophysical and Geochemical Exploration (IGGE) since 1978. They include certified reference materials of stream sediments (GSD1-14), soils (GSS1-16; ASA 1–6, for analysis of available elements), various rocks (GSR1-6, GSR13-15), biological material (GSV1-4 and GSB 1–10), synthetic silicates (GSES I 1–11) and limestones (GSES II 1–9 for spectral analysis). They also include geochemical reference materials for ore analysis: Cu-Pb-Zn ores (GSO1-4), Cu-Pb-Zn concentrates (GSO5-7), platinum-group element (PGE) ores (GPt5-6 and GPt9-10), silver ores (GAg1-6) and geochemical reference materials for Au (GAu8-14) and PGE determination (GPt1-4, and GPt7-8). A multi-laboratory collaborative analysis scheme was adopted in the certification procedure of the IGGE. Dozens of competent laboratories with hundreds of senior analysts in China participated in the certification analysis. These samples have been supplied to more than thirty countries and more than 4000 customers from national industrial, agricultural, environmental, scientific and educational fields. Most of the geochemical reference materials are used for the calibration of measuring apparatus, evaluation of analytical methods, certification studies, quality control and laboratory accreditation programmes.  相似文献   

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