【作者】 朴星海；

【导师】 王可勇；

【作者基本信息】 吉林大学 ， 矿物学、岩石学、矿床学， 2012， 硕士

【摘要】 研究区位于内蒙古自治区阿拉善盟额济纳旗境内，地处中亚荒漠东南部，靠近巴丹吉林沙漠的北部边缘，大地构造位置处于天山-阴山东西向构造带东段，甜水井-乌珠尔嘎顺-雅干成矿带。本人于2010年5月至2010年10月、2011年5月至2011年11月两次赴研究区，先后开展了1:25000土壤地球化学测量工作、1:25000地质草测、1:10000土壤地球化学综合剖面31.54km及2032m³的槽探等工作，其中取土壤地球化学样品3354件、岩石化学分析样品87件、薄片鉴定样品125件、包裹体测温样7件。通过2010²011年所做的野外及室内分析工作，取得以下成果：1、研究区主要出露地层为石炭系下石炭统的白山组（C₁b₁）与绿条山组（C₁l），白山组分为3个岩性段，即：C₁b₁¹、C₁b₁²和C₁b₁³；呈条带状分布于工区的主体部分，北东东-南西西方向展布。此外还圈定了出露在研究区东北部的北山群（Pt₁b）斜长片麻岩，而以往的区域资料中，在研究区内并未见北山群斜长片麻岩。区内断裂构造较为发育，规模相对较大，主要为贯穿预查区中南部的石块地-蓬勃山逆冲断层，总体走向为270～290°，北倾，倾角60°～70°。区内岩浆岩主要分布于北部、南部及东部边缘。侵入岩岩性主要为华力西期闪长岩，呈岩基和岩株状产出，集中分布于大断裂的两侧。2、通过野外工作及室内分析，研究区的主要成矿元素由原来的铜多金属确定为金元素，且区内金矿化类型较为单一，为石英脉型。石英脉主要受主断裂下盘的次级断裂控制，其矿化类型主要为硅化、黄铁矿化等。根据槽探工作所取得成果，在研究区内划分出8处品位大于0.1g/t的含矿石英脉，矿脉均产于横穿研究区的韧性剪切带南北两侧，整体呈北西向展布。3、对上述矿脉的流体包裹体研究表明：矿脉中气液两相包裹体为主体，约占80%以上，此外还见有含CO₂三相包裹体。通过包裹体测温算出流体总体盐度为2.22⁹.86wt%NaCl；均一温度为182³00℃。由流体包裹体测试结果中可看出，矿脉成矿流体为NaCI-CO₂-H₂O体系，且盐度较低，初步判断，其流体来源可能与岩浆水有关，且矿脉分布在地层与闪长岩体接触部位，说明成矿早期阶段主要为岩浆余热作用；从均一温度-盐度散点图中可看出成矿流体的密度为0.70～0.95g/cm³，集中的主要密度范围为0.85-0.90g/cm³，是属于低密度流体，初步判断晚期阶段与大气降水有关。4、通过对研究区的土壤地球化学测量，共圈出多元素异常66处，其中Au元素异常7处，有望异常分别为Au-HT10-4、Au-HT10-5、Au-HT10-6、Au-HT10-7号异常，为甲类异常；根据各元素异常的套合情况，研究区内又分出4处组合异常，具有异常规模较大，强度高，成矿地质条件有利，异常区石英脉极为发育等特点。通过对研究区3处局部的激电中梯剖面测量，共圈出9条高电阻异常带。5、综合考虑研究区的金元素土壤地球化学异常、土壤地球化学组合异常及激电中梯剖面异常所在的位置、异常特征及异常与地质体、矿脉的关系，结合地质条件，在研究区内圈定了三个找矿靶区。6、此外，为了进一步证实找矿靶区，工作组人员对3号靶区的Ⅵ、Ⅶ号矿脉进行了钻探工程，钻探工程编号分别为ZK009和ZK007。ZK009号钻孔是针对于Ⅵ号矿脉而设计，孔深为215m，共分19层，普遍见有硅化、绢云母化及绿泥石化现象，主要矿化类型为褐铁矿化及黄铁矿化，共取样品56个，取样测试Au品位在0.05⁰.47g/t。ZK007号钻孔设计在离Ⅶ号矿脉100m处，孔深为200m，共分17层，主要矿化类型为褐铁矿化及黄铁矿化，共取122个测试样品，测试结果Au品位在0.05².66g/t。钻探工程所取得成果，验证了找矿靶区的合理性，证实了该研究区具有非常好的成矿前景，为进一步探矿工作提供了有力依据。更多还原

【Abstract】 The study area in Ejinaqi of Alashan Union of Inner Mongolia is located at thesoutheastern part of Central Asia desert, near the northern margin of Jilin desert atBadan. The tectonic position is in the eastern Tianshan–Yinshan structure belt withWE trending and Tianshuijing–Wuzhuergashun–Yagan metallogenic belt.From May2010to October2010and May2011to November2011, respectively, theauthor investigated the study area. The major work were measurement of1:25000soilgeochemistry,1:25000simply geological measurement,1:10000soil geochemistryprofiles of which are31.54Km long and trenching of2032M³and so on. We selected3354samples of soil geochemistry, analyzed87petrochemistry samples, identified125thin sections and tested7inclusions. Based on our field and measurement workfrom2010to2011, we suggested that:1. The Lower Carboniferous Baishan group （C₁b₁） and Lvtiaoshan group （C₁l）arethe main strata in the study area. In northeastern part, we found the Early PaleozoicBeishan group （Pt₁b）,which are consisted mainly of plagioclase gneiss. It has neverbeen mentioned in the past regional references. Fault structures in the region werewell developed and the scale is relatively large. The most important fault throughoutsouth central research area is Shikuaishan-Pengboshan thrust fault, the main trend is270-290°, dig angle is60-70°and the direction is northward. A series of N-Sextensional faults and extensional-shear faults and shear faults with NW and NEtrends are subordinate. Magmatic rocks mainly distributed in the northern, southernand eastern margin. Intrusive rocks dominated by the Variscan diorites can be foundon both sides of the large faults. Diorites are characterized by batholiths and stock.2. The major ore-forming element of study area was identified as gold, notcopper-multielements. However, the gold mineralization type of study area isrelatively single, mainly the type of quartz vein that is our object research. Partly quartz veins are intensive, and the features are higher gold grade and some level ofscales. Quartz veins are generally controlled by the subordinate fractures of footwallsof main faults, and the mineralization types are siliconization, pyritization and so on.Based on the results of slot work, we divided the quartz veins into8places in ourstudy area. The grade is greater than0.1g/tons. All the veins distribute in the north andsouth sides of ductile shear zones which traversed our study area, and NW trending.3. According to study on the fluid inclusions of quartz veins, our results indicatedthat fluid inclusions can be divided into two types: two-phase inclusions of gas-liquidand three-phase inclusions combined with CO₂. The former one is dominated,accounting for more than80%. The major fluid salinity is2.23-9.86wt%NaCl.Uniform temperature range of inclusions is182–300℃. Testing results of fluidinclusions show that the ore-forming of veins is NaCI-CO₂-H₂O system, and thesalinity is low. We preliminary suggested that the source of fluid are probably relatedto magmatic water and the earlier stage of ore forming is mainly magmatic afterheateffect because the ore veins distribute in the contact part between stratum and dioritebody. Scatter diagram of uniform-salinity shows the density of ore-forming fluid is0.70-0.95g/cm3, the main density range are0.85-0.90g/cm3, therefore, theore-forming fluid is low density type, preliminarily indicating that the later stage ofore-forming is related to atmospheric precipitation.4. We analyzed the soil geochemistry data of study area and found66multi-element anomalitic places. There are7abnormal places of Au. Youwanganomalous is Au-HT10-4, Au-HT10-5, Au-HT10-6and Au-HT10-7, respectively.They all belong to A-class anomaly. Based on the overlap situation amongmulti-element anomaly, our study area can be divided into four places of assemblageanomaly. These places are characterized by large scale, high intensity, and favorableore-forming geological condition and well developed quartz veins in abnormal places.Based on the measurement of partly explosive electron middle grad sections anomaly,our study area can be divided into nine high resistance belts.5. Combined with soil geochemistry anomaly of Au, assemblage anomaly of soilgeochemistry, locations and anomaly features of explosive electron middle gradsections anomaly, relationship among anomaly, geological body and ore-vein,geological condition, we chose three prospecting target zones in our study area.6. In order to further confirm the prospecting target zones, we chose VI and VIIveins at No.3target zone and operated drilling engineering, and the drills were marketed as ZK009and ZK007. Drill of ZK009was designed for VI vein. Its depth is215M. This drilling can be divided into19layers. It is easy to find the phenomenonof siliconization, sericitization and chloritization on mineralized zones the mainmineralization types of which are limonitization and pyritization. We selected andtested56samples. The gold grade of samples is0.05-0.47g/t. Drills of ZK007is100M from the ore-vein of VII. The depth is200M. This drill can be divided into17layers. The main mineralization types are limonitization and pyritization. Testingresults of122samples show that the gold grade is0.05-2.66g/t.Our results from drilling engineering fully verified the reasonable of prospectingtarget zones, confirmed that the study area has a good mineralization prospect andprovided a strong evidence for future prospecting work更多还原