论文部分内容阅读
该矿田中热液铀矿床产于中生代花岗岩和下古生界沉积变质岩中,围绕着发育在这些岩石之上的白堊紀红盆分布。对矿床的成矿温度、成矿溶液成分和矿物稳定同位素进行了研究, 并讨论了成矿条件和成矿模式。按S、O、C同位素资料,花岗岩为S型,成矿热液为大气降水成因;矿源来自围岩。铀的搬运形式,矿前以[UO_2(CO_3)_2]~(2-)为主,矿期以[UO_2(CO_3)_2]~(2-)和[UO_2F_4]~(2-)为主。铀沉淀的主要原因是成矿溶液中络合物的配位体的减少和Eh值的降低。成矿时的物化条件是:温度为98—260℃,深度为1.5—2Km,压力为405—540大气压,pH_(150℃)为7.06,Eh_(150℃)为-0.490V,fo_2≈10~(-37)大气压,∑S为0.159M,∑U为8.7×10~(-4)M。指出发育在铀源体之上的断陷红盆是找寻大气降水成因热液铀矿床的重要找矿标志。
The Mesoproterozoic hydrothermal uranium deposit was found in Mesozoic granitoids and Lower Paleozoic sedimentary metamorphic rocks and distributed around the Cretaceous Red Basin developed above these rocks. The mineralization temperature, composition of ore-forming solution and stable isotopes of minerals are studied, and the metallogenic conditions and metallogenic models are discussed. According to the S, O, C isotopic data, granite is S type and mineralization hydrothermal fluid is the cause of atmospheric precipitation; the source rocks come from the surrounding rock. UO_2 (CO_3) _2] ~ (2-) is the dominant type of ore deposit in the mine, and mainly [UO_2 (CO_3) _2] ~ [2-] and [UO_2F_4] ~ (2-) The main reason for the uranium precipitation is the decrease of the ligand of the complex in the ore-forming solution and the decrease of the Eh value. The physicochemical conditions during mineralization are as follows: the temperature is 98-260 ℃, the depth is 1.5-2Km, the pressure is 405-540atm, the pH_ (150 ℃) is 7.06, the Eh_ (150 ℃) is -0.490V, fo_2≈10 ~ (-37) barometric pressure, ΣS is 0.159M, ΣU is 8.7 × 10 -4 M. It is pointed out that the fault-depression red basin developed over the uranium source is an important prospecting symbol for finding hydrothermal uranium deposits that cause the genesis of the atmosphere.