【作者】 张朋；

【导师】 孙景贵；

【作者基本信息】 吉林大学 ， 矿物学、岩石学、矿床学， 2010， 硕士

【摘要】 马连金矿区大地构造位置位于佳木斯隆起北部,该区已发现马连金矿床、蜂房沟金矿点、小马连沟金矿点和多处异常,其中马连金矿床较为典型,本文详细研究该矿床的成矿地质背景、矿床地质、流体包裹体特征和成矿时代,并对该区两个金矿点做了详细的地质调查研究与样品的室内分析工作,取得了如下认识:矿床地质特征表明:马连金矿床矿体以脉状为主,主要赋存于近南北向、北北东向和北北西向断裂带中,矿体的围岩为黑龙江岩群上岩组;矿石自然类型为石英脉型;矿石矿物主要有自然金、黄铁矿、黄铜矿和毒砂,脉石矿物主要为石英、碳酸盐、云母类和绿泥石;围岩蚀变明显,主要蚀变类型有硅化、绿帘石化、绿泥石化、阳起石化和碳酸盐化;根据矿体构造,矿石结构、构造,矿物共生组合特征,将矿床的矿化分为:石英-毒砂—黄铁矿阶段、石英-金属硫化物阶段和石英-碳酸盐阶段三个矿化阶段;蜂房沟金矿点和小马连沟金矿点与马连金矿床具有相似的地质特点,矿体围岩均为黑龙江岩群,矿体以石英脉为主,矿物组成为黄铁矿、石英、绢云母和高岭土,围岩蚀变主要有绢英岩化、泥化、青磐岩化等,蜂房沟金矿点可分为绢云母—黄铁矿、石英—黄铁矿和石英—高岭土三个矿化阶段。矿床流体包裹体研究表明:马连金矿床三个成矿阶段对应的成矿温度分别为:石英—毒砂—黄铁矿阶段:220℃～310℃;石英—金属硫化物阶段:180℃～220℃;石英—碳酸盐阶段阶段:120℃～180℃;通过流体包裹体相关参数计算得出:成矿压力为7.65～24.07MPa,成矿深度为0.97-1.79km。包裹体的气相成分主要为CO2、H2O和CH4,成矿流体总体为CO2-H2O-CH4体系;具有低盐度、低密度的流体特征,与国内外典型的造山型金矿床的流体性质有相似的特点;因此,初步确定该矿床为与造山带有关的中低温热液脉型金矿床;考虑到其它两个矿点成矿地质条件及流体包裹体特征与马连金矿相似,因此它们同属于造山型金矿。本次获得矿体围岩白云母钠长片岩的锆石U-Pb年龄为266.4±5.5 Ma,而构造折返退变质过程形成的白云母40Ar/39Ar等时线年龄为180Ma左右;因此,初步认为马连金矿床的成矿期为这期构造折返的伸展期,或早燕山期成矿。基于上述研究,我们得出:该矿床的含矿流体是在古生代古亚洲洋闭合,佳木斯地块向松嫩地块拼贴过程中产生,在随后的构造折返阶段聚集、上升到地壳浅部脆性域发生结晶沉淀作用而成矿。更多还原

【Abstract】 The Malian gold area was located in the north of Jiamusi upwarping,consists of Malian gold deposit,Fengfanggou and Xiaomaliangou mineral occurrence. The major strata outcropping in the area include Proterozoic Heilongjiang terrain, lower Cretaceous Ningyuancun Group (K1n),Taiqihe Group(K1t), Upper Cretaceous Fuminhe Group (K2f),Taipinlinchang Group (K2tp),Yuliangzi Group(K2yl),Cenozoic Neogene Pliocene-Oligocene Sunwu Group and Pleistocene-Holocene fluvial Facies sedimentation.The intrusive igneous rock mainly Proterozoic Era arkosic gneiss, ophite and Mesozoic Era ganite, ganite-porphyry and quartz vein ,tandileofite-porphyrite et al.The area structure are Neanticlinorium and NNE,EW,NS fault ,which development in Heilongjiang terrain.In the mining area, exposed strata is mainly upper-petrofabric of Heilongjiang terrain whereas the intrusive igneous rock mainly diorite,dacite-porphyrite,quartz vein,the structures are mainly multiple fold which is attitude is NE in the Heilongjiang terrain,and the fault attitude are NNE ,NNW ,NE ,SN et al. among them the SN and NW fault are formed before premetallogenic and metallizing phase,whereas the NE fault is the compressional faulting of the postmineralization,The mineralization type of the Malian gold deposit is sulfid altered mylonite type,while a small quantity of the orebody is sulfide quartz vein type,the most ore minerals are native gold, the syngenesispyrite ore minerals are pyrite, mispickel, which total content are less than 5%.the gangue mineral were quartz, plagioclase, carbonate, micagrou chlorite ,while there are also have some epidote,actinolite, illuderite, garnet, tourmaline , graphite et al. Accordance with formation orders, combination features and relationships of these minerals, mineralization can be divided into three phases: quartz—metal stoxida steage, quartz—gold—sulphide stage, quartz—calcite stage.The wall-rock alteration are mainly muscovitization, silication, epidotization, and pilitation,carbonatation and so on, in the deposit. The vicinity between gold- mineralization and the wall-rock alteration is the silication.The host rock of Fengfanggou and Xiaomaliangou mineral occurrence is Heilongjiang terrane, mineral occurrence is composed mainly of auriferous quartz veins, the ore minerals is mainly composed of pyrite and limonite, the gangue minerals is composed of quartz chlorite, sericite, epidote, the main texture of the ore bodies are semi-self-shaped, the main structure of ore bodies dissemination structure,There are many type of host rock alteration,such as ferritization sericitization and propylitization. Mineralization of Fengfangou mineral occurrence can be divided into three phases: Sericite—Pyrite steage, quartz—Pyrite stage, quartz—Kaolin stage.In Malian gold deposit , the fluid inclusions were devided into two types, the one is the gas-liquid two-phase ,which is the most fluid inclusion type of Malian gold deposit holding about 95%.According to the gas-liquid ratio ,this one also cloud be devided into 5%～30% and 30%～40% two types,the shape of the gas-liquid two-phase rotundatus,areellipse and irregular, the size were between 2-10μm, the hepredomination was 6μm,the other were pure gas or liquid inclusions,the shape of inclusions were elliptic,regular or irregular. homogenization temperature of NaCl-H2O fluid inclusions of two-phase is 140℃~310℃, and different temperatures correspond to different stages of mineralization; salinity is 0.5%～4.5% and density is 0.72-01.2g/cm3, so ore-forming fluids is the low-salinity, low-density fluid; calculated mineralized pressure is 7.65～24.07MPa, and forming depth is 0.97-1.79km; components by laser Raman studies have shown that gas compositions of inclusion are mainly CO2,H2O and CH4.The main ore-forming fluid which is CO2-CH4-H2O system shows the characteristics of metamorphic fluids.By studying the result of the previous data,combine with the features of the fluid inclusions obtained ,we can see that Malian gold deposit mineralization fluid hydrothermal are from the deep metamorphic mixed with the atmospheric precipitation. As the Heilongjiang terrane is one of the major source of minerals. As Fengfangou and Xiaomaliangou mineral occurrence has similainties with Malian gold deposit on geological features and fluid inclusions, suggests that they are the same type of gold deposit .Conclusion from the CL image analysis and LA-ICP-MS U-Pb age of testing of zircon in Muscovite albite schist shows that zircon in Muscovite albite schist include three groups:Ⅰ. Neopaleozoic early Permain (266.3±5.5 Ma),Ⅱ. Early Neopaleozoic ordovician (467～486Ma),Ⅲ. Mesozoic Era early Triassic (235～245Ma).The first group zircon is formation of zircon in crystallization processes for initial rock or limited the deposition age of the Heilongjiang terrane,within the previous data and our examination, we can limited that gold deposits of the ore-forming age is 180Ma.Combine with regional geologic characteristic,we can speculate that mineralized thermal power source of Malian gold deposits come from the orogenics between Jiamisi and Songnen massifs, to be influenced by Paleozoic Centeal Asian.Mineralized fluids reaulted in transformation between extrusion and extension during high pressure metamorphism,which occurred when subducting, turn back to superficial part.Mineral substance concentrated and deposited as surrounding rock eluvialed when fluid migration .From resarch result of the ore-forming age, mineralized material sources , mineralized thermal power source and ore-forming fluids shows that: As the Paleo-Asian Ocean closed,Jiamusi and Songnen massifs occoured collision,in deepness mineral-bearing fluids generated, As the rising progress along the fracture, Fluid is mixed by atmoshpere precipitation and leachied Heilongjiang Group resulting in obtaining part of ore-forming materials, ultimately is precipitate in the form of sulfur quartz vine ore body in the NE fault,which fromed Malian gold deposit and Fengfanggou and Xiaomaliangou mineral occurrence .Compared Malian gold deposit with some type domestic and overseas’orogenic gold deposit ,we found they have some common depaetments .So we concluded that Malian gold deposit which development in tectonic zones is orogentic gold deposit.更多还原