小秦岭地区大比例尺磁测方法找金效果

The effect of applying large scale magnetic measurement method to the prospecting for gold deposits in Xiao Qinling Mountains area

通过在小秦岭金矿区使用大比例尺磁测方法寻找地下金矿盲矿体的预测研究,及大量的野外磁测实验和工程验证的结果证明,在金矿生成的过程中,切穿深部的断裂构造与沿断裂带多期岩浆侵入活动以及地幔和断裂运动本身产生的热能,使含金丰度高的围岩地层重熔,运移、冷凝,致使金元素重新迁移分配集中,使构造带上有磁性的岩石发生退色退磁等变化,因而形成了区域性负磁异常区;使用高精度磁测方法,利用磁异常强弱及规模,圈定出与金矿体有关的矿化蚀变带较强地段的位置;笔者通过几个实例,阐述了应用磁测方法圈定与金有关的矿化富集段位置的具体做法,使磁测方法在寻找与金矿体有关的矿化蚀变带方面发挥了重要作用。

The large-scale magnetic measurement for the prediction of gold blind orebodies in the depth and lots of field magnetic measurement tests and engineering verifications demonstrate that,during the formation of gold deposit,the thermal energy produced by faulted structure cutting through the depth and the multi-periodic magmatic invasion as well as the movement of the mantle and faulting resulted in the remelting,migration and chilling of the gold-rich wall rocks and thus caused the remigration,redistribution and re-concentration of gold,leading to the decoloration and demagnetization of magnetic rocks along the structural zone and the formation of regional negative magnetic anomaly area. Using the high precision magnetic measurement method and utilizing the intensity and scale of the magnetic anomaly,we can delineate the gold-related segment characterized by relatively strong mineralization and alteration. With some practical examples,the authors describe the concrete working method for applying magnetic measurement method to delineating gold-related mineralization enrichment segment,with the purpose of making the magnetic measurement method play an important role in search for gold-related mineralization- alteration zone.