摘要
平和—安溪火山—侵入杂岩区,金的区域平均含量很低,为0.82ppb。10ppb 是不同级别含量变化的一个转折点,可作为本区金异常和背景的分界值。在各类岩石中,金主要趋向富集于空落相火山碎屑岩类及中酸性喷溢相的凝灰熔岩和熔岩类中,平均变化于0.77—1.98ppb,但以石英斑岩含量最高,为2.39ppb。金的矿化、异常可赋存于不同岩石类型中,各类蚀变岩、构造岩和硫化物矿石中金的含量有明显的大幅度提高,最高达23克/吨,说明金在火山—侵入岩浆活动后期的热液活动中存在着金的活化、迁移、再生和叠生作用。因此,在火山—侵入杂岩区,只要有一定的有利构造部位和适合的物理化学条件,金是可能富集成矿的。
The average gold content in the area is about 0.82ppb,and 10ppb is a discriminating value for dif-ferent grades of gold content which can be treated as a critical limit between gold anomaly and back-ground value in Pinghe-Anxi volcanic area.The gold among different rocks generally tends to concen-trate in airfall facies of pyroclasts,intermediate-acidic effusive facies of tuff lava and lava within a con-tent range of 0.77—1.98ppb,but with maximum content of 2.39ppb in quartz porphyry.Both goldmineralization and gold anomaly can be found in different types of rocks while gold content among dif-ferent alterated rocks,structural rocks and sulfide ore have an obvious increase (max.23g/t) which re-veals that there are activation,migration,palingenesis,and superposition of gold during hydrothermalactivity of late-phase volcanic-intrusive magmatism.Consequently,there is a possibility of gold concen-tration to form ore deposit if a favourable structural location and suitable physicochemical conditions ex-ist in volcanic-intrusive complex area.
出处
《福建地质》
1990年第4期248-255,共8页
Geology of Fujian
