蒙古国道尔脑德铀矿床地质特征及找矿方向

道尔脑德铀矿床位于西伯利亚板块南缘的克鲁伦-额尔古纳微陆块的边缘盆地中，作为阿尔贡（Argun）蒙古铀矿省的重要组成部分，该矿床的形成与道尔脑德火山机构密切相关，属于中-低温火山热液型矿床。通过开展矿区地质调查发现，该矿床主要受NE、NW向断裂和层间裂隙的控制，呈脉状、网脉状和层状产出；矿石矿物以含铀矿物为主，包括水硅铀矿、沥青铀矿、钛铀矿和铀的钛酸盐等，脉石矿物包括铁硫化物、钛氧化物和部分沉积的含碳物质；矿床中还发育有泥化、硅化、赤铁矿化等典型的氟-钼-铀型矿床的围岩蚀变。根据前人测得的道尔脑德火山岩同位素年龄（170~140 Ma），以及铀矿化叠加在乌兰铅锌多金属矿床之上等间接证据，认为该区铀矿化形成时代很可能是早白垩世。该矿床处于火山-沉积盆地中，成矿背景优越，矿化蚀变较发育，且该区构造分布广泛，具有较大的找矿潜力。

Geological Feature and Prospecting Direction of Dornod Uranium Deposit in Mongolia

Dornod uranium deposit is located in the marginal basin of Kunlun-Erguna microcontinent that is on the southern margin of the Siberian Plate.As an important component of Argun Mongolia uranium Province，the formation of the deposit is closely related to the Dornod volcano apparatus and it belongs to middle-low temperature volcanic hydrothermal deposit.According to geological survey of ore district，it is found that the deposit is mainly controlled by NE and NW faults and interbedded fractures，which shows pulse，net pulse and stratiform output.Ore minerals are mainly composed of coffinite，include uraninite，brannerite and uranium titanate，gangue minerals include iron sulfide，titanium oxide and partially deposited carbonaceous material.The rock alteration of typical F-Mo-U deposit are also developed in the deposit，such as argillization，silicification，hematite，and so on.The isotopic age of Dornod volcanic rocks measured by predecessors is 170~140 Ma，and indirect evidence is obtained from uranium mineralization superimposed on the Ulan Pb-Zn polymetallic deposit in this area，therefore，it is considered that the age of uranium mineralization in this area is likely to be early Cretaceous.The deposit is located in the volcanic-sedimentary basin with favorable metallogenic background and mineralized alteration and widely distributed struture，the uranium deposit has great prospecting potential.