Electromagnetic and geoelectric investigation of the Gurinai Structure, Inner Mongolia, NW China   总被引：2，自引：0，他引：2  

S. Hlz  D. Polag  M. Becken  R. Fiedler-Volmer  H.C. Zhang  K. Hartmann  H. Burkhardt 《Tectonophysics》2007,445(1-2):26

In three field campaigns between the years 2000 and 2004 geophysical measurements were conducted in the Ejina Basin, NW China. Research work in the year 2004, which is described in this paper, was concentrated on the Gurinai Structure (101°25′E, 41°N) situated in the southeastern part of the Ejina Basin in transition to the dune fields of the Badain Jaran Shamo. On satellite images the Gurinai Structure can be identified by two almost 100 km long, subparallel, N–S-striking lineaments, which may indicate tectonic deformations of late Quaternary sediments. To get a coherent picture of the structure a geophysical survey employing three electromagnetic methods – magnetotellurics (MT), transient electromagnetics (TEM), and geoelectrics (DC) – has been conducted to map the subsurface resistivity at different depth scales.The geophysical data interpretation for shallow and intermediate depth down to a few hundred meters links the subsurface distribution of electric resistivity to geomorphological units known from field work in reference with satellite images. The westerly lineament of the Gurinai Structure coincides with a subvertical change in electric resistivity. Together with geomorphological indications from fieldwork and the analysis of elevation data (SRTM), a tectonic deformation of unconsolidated sediments along a fault with an extensional component is interpreted. In the central and eastern part of the Gurinai Structure a shallow resistive subsurface layer can be traced into the first dunes of the Badain Jaran Shamo. This resistive subsurface layer is linked to the presence of fresh water, indicating infiltration from the dune field. Also, in the eastern part of the Gurinai Structure a resistive, approximately ENE-striking feature can be seen at intermediate depth, which is interpreted as a crystalline basement ridge. Towards the southern margin of the Gurinai Structure a trough-shaped unit with low resistivities and a thickness of about 1 km is identified and can be explained by a sediment package saturated with fluids of high salinity or substantial amounts of clay. The strike direction of the structure can be connected to the regional pattern of tectonic faults and seismicity.The interpretation of electromagnetic data at various depth scales contributes to the general understanding of the Ejina Basin's buildup and tectonic setting in the vicinity of the Gurinai Structure.  相似文献   

Groundwater replenishment analysis by using natural isotopes in Ejina Basin, Northwestern China   总被引：4，自引：0，他引：4  

Yinghua Zhang  Y. Wu  J. Su  X. Wen  F. Liu 《Environmental Geology》2005,48(1):6-14

The Ejina Basin underlying complex aquifers is located in the lower reaches of the Heihe River with an arid climate and 40 mm mean annual precipitation. As the balance of the natural ecosystem in the Ejina Basin is fragile and easily upset, it is very important to estimate and rationally use the limited groundwater resources to maintain the balance. Water samples were collected from the Heihe River and wells for chemical and isotopic measurements across the basin. The Piper diagram gives two main types of hydrochemical features. Against the background of the regional geology, combining isotope ¹⁸O, tritium, and chemical analysis with groundwater flows indicated by a shallow groundwater level contour map, different kinds of groundwater sources and ways to replenish groundwater were discovered. North of the study area are artesian wells that are replenished by the mountainous area at the boundary between China and Mongolia. Replenishment for most of the groundwater resources of the Gurinai oasis comes from the Heihe River seepage flow of the highly conductive paleochannel, not from the Badain Jaran Desert as indicated by TDS and tritium analysis. The different groundwater ages which are younger than 35 years were approximately estimated by radioactive isotope tritium (T). By such efforts, groundwater resources can be effectively evaluated with the engineering impact of the Heihe River Project.  相似文献   

额济纳绿洲夏末典型晴天小气候特征分析   总被引：5，自引：3，他引：5  

张艳武  冯起  吕世华  黄静  司建华  苏永红 《高原气象》2005,24(4):516-521

绿洲系统特有的地理地貌形成了绿洲特殊的小气候特征。利用额济纳绿洲2003年9月8～10日小气候观测资料，分析了绿洲柽柳林的小气候特征。在柽柳林内，地表和近地层大气温度有明显的日变化，日间地表给大气加热，大气温度呈超绝热递减率随高度递减；夜间大气给地表加热，大气为稳定层结。近地层空气湿度的日变化与温度相反。林内空气温度的垂直分布主要取决于冠层与地表吸收太阳辐射状况。在林冠顶层，白天以上升气流为主，夜间以下沉气流为主，绿洲荒漠环流效应已经不明显。绿洲上空大气浑浊度小，对太阳辐射的削减较少，绿洲具有很好的光资源背景。  相似文献   

苏尼特左旗地区海西末——印支期构造活动特征   总被引：2，自引：0，他引：2  

高德臻 《地质力学学报》2000,6(1):52-58

该文对内蒙古苏尼特左旗地区NNE向褶皱的形态、褶皱成生时承受的轴向载荷、压缩量乃至断裂及韧性剪切带的形态和变形域进行了对比研究,划分了变形序次。在此基础上认为该区存在印支运动的构造形迹,且该形迹是在海西末期形成的构造形迹的基础上,在同一区域构造应力场持续作用下递进变形的产物。   相似文献   

中国北方农牧交错地区农牧业生产模型及应用:Ⅱ.应用     

张琦峰  李振山  王涛 《中国沙漠》2007,27(1):40-45

以奈曼旗为例,根据农牧业生产综合模型对农牧业生产的主要方面进行了分析。农牧业生产中,资本对产出的贡献最大,有效劳动和土地生产力次之,表明奈曼旗的生产处于规模报酬递增的增长时期。农牧业生产基本呈指数增长,且1951-1980年增长较缓,1980年以后增长很快。固定资本的增长较为稳定和缓慢,生产费用的增长具有波动性。生产费用与施肥量和沙漠化程度关系显著,当年生产费用与上年产出高度相关,同时由于生产费用对产出增加有很高的贡献,说明农牧交错区的农牧业发展中存在负反馈关系。土地生产潜力利用率反映了农牧业生产与土地生产力之间的关系,该利用率在0~0\^4之间波动,并且1980年以前利用率低且波动小,说明这段时期的农牧业生产整体水平不高,1980年以后利用率高且波动大,资本对产出贡献的比重下降,土地生产潜力的重要性相对增大。  相似文献   

内蒙古奈曼旗中部沙地土壤剖面特征     

赵学勇  张铜会  常学礼 《中国沙漠》2000,20(Z1):45-47

通过对奈曼旗中部不同沙地土壤剖面特征和有机质含量分布的分析认为:灌溉农田土壤具有8层结构,沙层与粘土层交错叠置。旱作农田土壤虽然也具有8层结构,但是只有一层粘土,撂荒地土壤只有3层,而且完全是沙层,保水保肥性能最差。此外,灌溉农田土壤0~30 cm土层的有机质的含量约0.712 g·cm^-3,旱作农田和撂荒地相应土壤层的有机质含量分别只有0.403g·cm^-3和0.420 g·cm^-3。同一土壤剖面的有机质含量随着深度的增加而减少。  相似文献   

内蒙古1017高地银多金属矿床地质地球化学特征及成因探讨     

王治华  葛良胜  孙磊  常春郊  丛润祥  张慧玉 《矿物岩石》2015,35(1)

1017高地银多金属矿床位于内蒙古自治区东乌珠穆沁旗,矿区大地构造位置处于西伯利亚板块东南缘查干敖包-奥尤特-朝不楞早古生代构造-岩浆岩带东段。石英脉型矿石中流体包裹体研究显示,从成矿早期到主成矿期,流体温度逐渐降低(从404℃~134℃到236℃~121℃),盐度都为中低盐度,由此表明该矿床具有浅成、中低温、中低盐度热液成矿特征。激光拉曼光谱分析显示包裹体气液相成分主要为H2O。矿石硫同位素组成相对均一,δ34S介于3.4‰~8.0‰之间,均值5.35‰,与幔源S的δ34S值(介于-3‰~3.0‰之间)比较,有向沉积硫的明显漂移,表明矿石中硫来源于沉积硫与岩浆硫的混合、平衡作用;矿石硫化物铅同位素比值没有明显的差别,206Pb/204Pb值为18.274 0~18.399 6,207Pb/204Pb值为15.539 9~15.561 6,208Pb/204Pb值为38.036 3~38.177 2,具有钍铅微弱亏损特征,指示矿石中硫化物的铅源主要来自地壳深部的岩浆源区,伴随岩浆及其热液作用,不可避免地混入了部分富放射成因铅的地壳物质。矿石氢氧同位素组成为:δDV-SMOW值介于-103‰~-125‰之间,δ18 OV-SMOW值在6.9‰~13.9‰之间,显示成矿流体中的水来源于岩浆水与大气降水的混合。综合1017高地银多金属矿床的地质特征和流体包裹体、S,Pb,H,O同位素研究认为,该矿床成矿物质来源于深源岩浆和上地壳的混合,成矿流体主要来自岩浆期后热液和大气降水,其成因类型可归于中低温度、中低盐度的岩浆期后热液型银多金属矿床。  相似文献   

内蒙古阿巴嘎旗北部铜多金属矿地质矿产特征及找矿方向   总被引：1，自引：1，他引：0  

郭灵俊  赵志军  崔来旺  杨波  连世恩 《地球学报》2011,32(1):57-63

内蒙古阿巴嘎旗北部巴彦德勒-格勒敖包四幅1:5万矿产远景调查查明了本区成矿优势矿种为铜、铅、锌、银、锡,伴生金和铋,圈定了多处可供进一步勘查的铜等多金属找矿靶区.本文在论述本区成矿地质条件和控矿因素的基础上,通过哈达特陶勒盖-高尔旗-莫若格钦银多金属矿集区、准乌日斯哈拉锡多金属找矿靶区、阿扎哈达-格勒敖包-图拉格铜多金...  相似文献   

内蒙古苏尼特左旗北达布锡勒图岩体主微量元素地球化学特征及成因探讨          下载免费PDF全文

杨永胜孙柏年  康鸿杰邢伟伟李小强  何文龙王 磊 《中国地质》2011,38(2):301-316

达布锡勒图岩体位于华北板块与西伯利亚板块兴蒙造山带中的二连-贺根山缝合线北侧附近.通过对岩体各类岩性样品进行稀土和微量元素含量分析,结果显示,花岗闪长岩类(包括黑云花岗闪长岩和花岗闪长岩)成因类型为I-S过渡型花岗岩,成岩岩浆可能为大洋俯冲板片和上覆陆壳变杂砂岩部分融熔的混合岩浆,花岗岩类(包括二长花岗岩、黑云花岗岩和钾长花岗岩)为S-型花岗岩,原岩为变质泥岩,均产出于大陆弧构造环境,非埃达克质岩石.  相似文献   

内蒙古西部额济纳旗及邻区石炭系—二叠系烃源岩演化特征及影响因素     

魏建设  卢进才  魏仙样  姜亭 《中国区域地质》2011,(6):895-903

通过对额济纳旗及其邻区石炭系—二叠系烃源岩演化程度的平面展布和纵向分布特征的研究,结合对华力西中晚期—喜马拉雅期侵入岩露头分布和构造活动特征的分析,认为华力西晚期、燕山期侵入岩与构造活动对区内石炭系—二叠系烃源岩的演化程度影响较大,印支期侵入岩和构造活动仅对部分地区烃源岩成熟度有影响,喜马拉雅期构造活动对区内烃源岩演化程度无影响。区内石炭系—二叠系系阿木山组（干泉组）和下—中二叠统菊石滩组烃源岩过成熟主要受华力西晚期侵入岩和构造活动的影响,上二叠统哈尔苏海组烃源岩演化程度受燕山期侵入岩和构造活动的影响。明确了不同期次侵入岩和构造活动对石炭系—二叠系烃源岩演化程度影响的平面展布特征。综合研究认为,区内石炭系—二叠系烃源岩不存在区域变质,成熟度总体为成熟—高成熟,部分剖面（井）烃源岩演化程度较高（达到过成熟）,是由侵入岩的热接触变质和构造活动的动力变质造成的。石炭系—二叠系沉积之后,岩浆活动和构造活动相对较弱的地区石炭系—二叠系烃源岩演化程度适中,为成熟—高成熟。  相似文献