摘要
笔者对小秦岭驾鹿构造蚀变岩型金矿的钾长石用红外光谱和X射线粉晶衍射法测定其结构态与平衡温度 ,结果如下 :钾长石为微斜长石 -最大微斜长石 ,Al的占位率t1(o) =0 .73～ 1.0 0 ,t1(m) =0 .2 6～ 0 ;t2 (o) =t2 (m) =0 .0 3～ 0 ;晶胞参数a0 =0 .8388～ 0 .86 11nm ,b0 =1.2 837～ 1.2 96 8nm ,c0 =0 .7156～ 0 .72 4 8nm ,α =89.90 6～ 91.0 93° ,β =115.6 50～ 116 .2 30° ,γ=87.50 0～ 89.994° ;三斜度Δ =0 .6 86～ 1.115;平衡温度t =50 3.51～ 578.35℃。因此 ,认为驾鹿钾长石是热液蚀变的产物 ,它调整结构所释放的热量对早期高温阶段的含金热液有影响 ,起着一种活化金络合物的作用 ,不利于金沉淀就位。随着钾长石平衡温度的降低和三斜度的升高 ,这种作用相对更加明显。
Using infrared spectroscopy and X_ray powder diffraction method, the authors have determined the structural ordering state and equilibrium temperature of K_feldspar collected from the Jialu gold deposit in Xiaoqinling which belongs to the faulted altered rock type. The K_feldspar is microcline to maximum microcline, whose Al occupancy t 1(o) =0.73～1.00, t 1(m) =0.26～0, t 2(o) =t 2(m) =0.03～0, with lattice parameters a 0=0.8388～0.8611 nm, b 0= 1.2837 ～ 1.2968 nm , c 0=0.7156～0.7248 nm, α =89.906～91.093°, β = 115.650 ～ 116.230° , γ = 87.500 ～ 89.994° . The triclinicity Δ=0.686～1.115, and the equilibrium temperature t =503.51～578.35℃. Based on the above results, this paper has also dealt with the relationship between the equilibrium temperature of K_feldspar and gold mineralization. The authors hold that Jialu K_feldspar is product of hydrothermal metasomatism, and its heat released in the course of adjusting structural state must have made an impact on the auriferous hydrothermal solution at the early high_temperature stage, thus activating gold complex. This action was unfavorable for gold precipitation, as is more clearly seen with the lowering of the equilibrium temperature and the rising of the triclinicity.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2000年第2期167-173,共7页
Acta Petrologica et Mineralogica
基金
中国科学院王宽诚博士后奖励基金
广东省博士后科学基金
关键词
金矿床
钾长石
结构态
平衡温度
成矿意义
K_feldspar
Al-Si ordering
structural state
equilibrium temperature
ore_forming significance Jialu gold deposit
