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分析了云南老王寨金矿区煌斑岩的Sr,Nd同位素组成和固定铵的含量。与原始地幔现代值相比,本区煌斑岩具有相对高~(87)Sr/~(86)Sr比值(0.70644～0.70895)和低~(143)Nd/~(144)Nd比值(0.512436～0.512524);岩石固定铵(NH_4~+)含量(74.34×10~(-6)～468.72×10~(-6))明显高于其他幔源岩石(1×10~(-6)～27×10~(-6)),低于矿区炭质围岩(799.60×10~(-6)～1742.46×10~(-6))的固定铵含量。结合地球化学资料及有关模拟计算结果,认为本区煌斑岩具有上述Sr,Nd同位素组成和固定铵含量特征,可能不是“基性岩浆陆壳混染”的产物,而是富集地幔源区部分熔融的结果。
The Sr, Nd isotopic compositions and the contents of ammonium in the lamprophyre of Laowangzhai gold deposit in Yunnan Province were analyzed. Compared with the modern mantle values, the lamprophyres in this area have a relatively high 87 Sr / 86 Sr ratio of 0.70644-0.70895 and a low 143 Nd / 144 Nd ratio of 0.512436 ~ 0.512524). The contents of NH_4 ~ + (74.34 × 10 ~ (-6) ~ 468.72 × 10 ~ (-6)) were significantly higher than those of other mantle rocks (1 × 10 ~ (-6) ~ 27 × 10 ~ (-6)), which is lower than the fixed ammonium content of carbonaceous rock mass in the mining area (799.60 × 10 -6 ~ 1742.46 × 10 -6). Based on the geochemical data and the results of simulation, it is considered that the lamprophyres in this area have the characteristics of Sr, Nd isotopes and fixed ammonium content mentioned above and may not be the product of “mafic continental crustal contamination” Partial melting results.