胶东金矿成岩成矿深度测算方法探讨

Discussion on the Method for Calculating Diagenetic and Metallogenic Depthsin the Jiaodong Gold Deposit

胶东金矿的储量和产量分别占全国的四分之一和三分之一。胶东地区的金矿成矿理论正经历着随地质科技发展而不断研究、讨论、发展和创新的过程。胶东西北部的新城金矿是胶东蚀变岩型金矿的典型代表,同时也是重要的生产矿山之一。随着国家对于矿产安全保障重视程度的不断提高,胶东地区深部找矿增储的迫切需求也随之而来。在矿产勘查领域,尤其是深部找矿过程中,成岩深度、成矿深度和剥蚀深度测算是重要的地质学方法。因此,本文选取新城金矿作为胶东地区的典型金矿代表,探讨其成岩、成矿和剥蚀深度的测算方法及应用。采用矿物压力计算方法,推算得到新城的成矿岩体———郭家岭花岗闪长岩的平均成岩深度为3 km;采用成矿深度构造校正方法,推算得到新城金矿的蚀变成矿平均深度为2 km;采用裂变径迹分析方法,得到新城金矿成矿后的剥蚀深度约为2.5 km。在上述成岩深度、成矿深度和剥蚀深度测算结果的基础上,深入讨论胶东地区的金矿成矿规律和深部预测问题。研究区的生产勘探工作证明,本文的成矿深度计算结果与现已认识的深部成矿规律相吻合,研究成果对胶东金矿及其他相关类型的热液金属矿床的深部找矿工作有重要的参考价值。

The reserves and production of the Jiaodong gold deposit account for one-quarter and one-third of China's totals,respectively.The gold mineralization theory in the Jiaodong area is continuously evolving through ongoing research,discussion,development,and innovation,driven by advances in geological science and tech-nology.The Xincheng gold deposit in Northwestern Jiaodong is a representative example of altered-rock type gold deposits and is also one of the key production mines.With the state's increasing attention to mineral resource safety,there is an urgent need for deep exploration and resource storage in the Jiaodong area.In the mineral exploration,particularly for deep prospecting,the estimation of diagenetic depth,metallogenic depth,and denudation depth is an important prospecting method and geological theory.Therefore,this study selects the Xincheng gold mine as a case study to discuss the methods and applications for measuring or calculating the depths of diagenesis,mineralization,and denudation.Using the Xincheng gold deposit as an example,the average diagenetic depth of the Guojialing granodiorite,the ore-host rock mass,is estimated to be 3 km based on calculated mineral formation pressure.The average depth of erosion and transformation of the Xincheng gold deposit is estimated to be 2 km using the correction method for metallogenic depth.Fission track analysis indi-cates that the post-mineralization denudation depth of the Xincheng gold deposit is approximately 2.5 km.Based on the above calculation results,we discuss the metallogenic patterns and predictions for gold deposit depths in the Jiaodong area.The production and exploration work in the study area has confirmed that the metal-logenic depths calculated in this study are consistent with the principles of mineralization formed in depth,pro-viding important reference value for deep ore prospecting in the Jiaodong gold deposit and other types of hydrothermal metal deposits.