胶东三山岛北部海域金矿床石英热释光和晶胞参数特征及其找矿意义

胶东是中国最重要的黄金资源基地之一,近年来深部找矿取得重大突破,特别是在三山岛北部海域发现超大型金矿床。深入研究其成矿规律,对于指导今后的找矿勘探意义重大。笔者应用成因矿物学和找矿矿物学理论,选取该矿床的贯通性矿物石英,对其热释光和晶胞参数特征的时空分布规律及与金矿化的关系进行了系统研究。结果表明:(1)石英热释光曲线以中温单峰、肩峰和不对称双峰为特征。主成矿阶段发光曲线出现中温峰和高温峰的双峰,发光强度大;(2)石英热释光峰位温度、发光强度在垂向上的波动变化与矿石金品位套合较好;(3)石英(Δa₀/a₀)/(Δc₀/c₀)值的变化范围在1.92~3.30,指示微量元素进入石英的方式以填隙为主;(4)随着成矿阶段由早至晚,石英晶胞参数a₀和V₀逐渐升高,c₀/a₀逐渐降低,表明石英的晶胞参数可作为识别其结晶阶段的标识之一;(5)钻孔深部石英热释光峰位温度较高,发光强度波动性较大,峰型呈单峰和肩峰,石英晶胞参数a₀、V₀仍较大,指示该矿深部仍有较好的找矿前景。

Characteristics and prospecting significance of thermoluminescence patterns and cell parameters of quartz from the undersea gold deposit off northern Sanshandao,Jiaodong Peninsula

The Jiaodong Peninsula is one of the most important bases of gold resources in China. In recent years, great breakthroughs have been made in deep prospecting of gold deposits, especially a super large undersea gold deposit off northern Sanshandao has been discovered. Presently only limited research has been done on this deposit. Based on the genetic and mineral prospecting theory, we systematically studied the temporospatial distribution patterns of thermoluminescence and cell parameters of connective mineral quartz from the deposit. We found the following typomorphic characteristics of quartz very important for gold prospecting: (1) The quartz thermoluminescence curves showed characteristic singlet and shoulder-like peaks at the mid range temperatures in the early and late mineralization stages, and an asymmetric doublet peak with the strongest emission intensity over the mid-to-high temperature range in the main mineralization stage. (2) The peak temperatures and emission intensities on the thermoluminescence curves showed vertical fluctuations in volatility correlating with gold mineralization. (3) Quartz (Δa₀/a₀)/(Δc₀/c₀) values ranged between 1.92 and 3.30, indicating gap filling was the major way of incorporating trace elements into quartz. (4) Spatiotemporal variation of quartz cell parameters followed a clear pattern of increasing a₀ and V₀, decreasing c₀/a₀ from the early to late mineralization stages, indicating temperature and elemental impurity had an influence on quartz cell parameters. (5) In the depth of the ore body, the quartz thermoluminescence curves showed higher peak temperature, larger emission intensity fluctuation, singlet and shoulder-like peaks, and large a₀ and V₀ values, suggesting a good downward mineralization prospect.