摘要:
芨岭铀矿是中国北方最典型的钠交代型铀矿床之一, 文章通过对芨岭矿床ZKJ9-4钻孔深部所见含矿蚀变闪长岩、近矿蚀变闪长岩、远矿蚀变闪长岩、闪长岩原岩地球化学特征和组分迁移计算及矿体中心部位的淡粉红色方解石脉流体包裹体特征、均一温度、盐度和激光拉曼光谱研究, 认为芨岭钠交代型铀矿床的成矿流体含有大量碳酸铀酰络合物[UO2(CO3)2]2–和[UO2(CO3)2]4–的同时还含有丰富的SiO2、Na+、Ca2+、Mg2+、Fe2+、Mn2+、∑REE、U、Th、Ga、Sr、Zr、Ba、Rb、Nb、Mo、Cd、Sn、Hf、Ti、Ta、CO2、H2S和 CH4等组分, 成矿流体具有较强的还原性, 并对 MnO、K2O、Cr 和 Co 具有较强的交代溶蚀作用.成矿流体是起源于岩浆演化晚期的再平衡岩浆水, 热液温度为(300±20) ℃, 盐度为2.99 wt%~4.57 wt% NaCl,密度为0.75~0.77 g/cm3.流体沸腾是芨岭钠交代型铀矿成矿物质的早期卸载机制, 晚期成矿流体中加入了大量的大气降水, 流体混合作用进一步促进了成矿物质的卸载.
Abstract:
The Jiling uranium deposit is the most typical Na-metasomatic uranium deposit in North China. In this paper, the authors studied the geochemical characteristics of ore-bearing altered diorite, near-ore altered diorite, distal altered diorite and diorite, calculated component migration, fluid inclusions characteristics, homogenization temperatures, salinity, and made Raman analysis of light pink calcite vein in drill hole ZKJ9-4. The results show that the hydrothermal fluid is rebalance water from evolved magma, which has rich U in the forms of [UO2(CO3)2]2–and [UO2(CO3)2]4–, together with abundant SiO2, Na+, Ca2+, Mg2+, Fe2+, Mn2+, ∑REE, U, Th, Ga, Sr, Zr, Ba, Rb, Nb, Mo, Cd, Sn, Hf, Ti, Ta, CO2, H2S, CH4, and some other components. The temperature of ore-forming fluid is (300±20) ℃, the salinity is 2.99 wt%~4.57 wt% NaCl, and the density is 0.75~0.77 g/cm3. Fluid boiling was the ore-forming mechanism of early period hydrothermal fluid, while late period fluid was mixed with meteoric water, and the fluid mixing further promoted U unloading.
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