1 区域地质概况
图1 冈底斯带区域地质图及主要斑岩型铜矿床分布(修改自Wu et al,2016;郑有业等,2021)BNSZ-班公湖—怒江缝合带;SNMZ-狮泉河—纳木错—嘉黎缝合带;LYZSZ-雅鲁藏布江缝合带;LMF-洛巴堆—米拉山断裂带;1.冈底斯岩基;2.林子宗火山岩;3.渐新世—中新世花岗岩;4.蛇绿混杂岩带;5.Cu-Mo矿床;6.Mo-Cu/Mo矿床;7.研究区 Fig. 1 Regional geological map of Gangdise belt and distribution of main porphyry copper deposits(modified after Wu et al,2016;Zheng et al,2021) |
2 样品及分析方法
2.1 样品描述
2.2 分析方法
3 分析结果
3.1 主量元素
表1 西藏达局地区电气石主量元素分析结果Table 1 Analysis results of main elements of tourmaline in Daju area,Xizang(%) |
| 类型 | 样品编号 | SiO2 | TiO2 | Al2O3 | Cr2O3 | FeO | MgO | CaO | MnO | Na2O | K2O | F |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tur-Ⅰ | Tur1-3-2 | 35.01 | 0.89 | 28.79 | 0.03 | 11.03 | 6.72 | 0.36 | 0.01 | 2.36 | 0.03 | 0.17 |
| Tur1-3-3 | 35.25 | 0.16 | 28.78 | - | 11.14 | 7.31 | 0.12 | 0.01 | 2.22 | 0.03 | - | |
| Tur2-6-1 | 35.21 | 0.23 | 29.86 | - | 10.72 | 6.53 | 0.23 | 0.00 | 2.43 | 0.05 | 0.09 | |
| Tur2-6-2 | 35.37 | 0.34 | 29.75 | - | 10.63 | 6.50 | 0.25 | 0.03 | 2.37 | 0.07 | 0.02 | |
| Tur2-6-3 | 35.60 | 0.20 | 29.55 | - | 10.72 | 6.91 | 0.21 | 0.01 | 2.45 | 0.08 | 0.05 | |
| Tur-Ⅱ | Tur1-3-4 | 35.46 | 0.20 | 30.51 | 0.01 | 9.82 | 6.44 | 0.17 | - | 2.34 | 0.06 | 0.04 |
| Tur1-3-5 | 35.30 | 0.29 | 30.42 | 0.03 | 10.26 | 6.24 | 0.19 | 0.03 | 2.44 | 0.06 | 0.01 | |
| Tur1-3-7 | 35.23 | 0.81 | 29.21 | 0.14 | 11.00 | 6.53 | 0.26 | 0.05 | 2.42 | 0.02 | 0.22 | |
| Tur1-3-11 | 35.72 | 0.24 | 31.47 | 0.01 | 9.05 | 6.53 | 0.22 | - | 2.43 | 0.05 | 0.08 | |
| Tur2-3-1 | 35.70 | 0.10 | 30.38 | 0.04 | 10.33 | 6.66 | 0.18 | 0.05 | 2.63 | 0.06 | 0.01 | |
| Tur2-3-2 | 35.60 | 0.14 | 31.01 | 0.11 | 9.74 | 6.78 | 0.21 | 0.03 | 2.60 | 0.06 | 0.05 | |
| Tur2-3-3 | 35.24 | 0.21 | 30.10 | - | 10.02 | 6.72 | 0.20 | 0.02 | 2.51 | 0.06 | 0.05 | |
| Tur2-3-4 | 35.10 | 0.20 | 29.51 | 0.00 | 10.70 | 6.57 | 0.14 | 0.04 | 2.50 | 0.12 | 0.03 | |
| Tur2-3-5 | 35.40 | 1.17 | 28.39 | 0.01 | 11.30 | 6.49 | 0.32 | - | 2.30 | 0.08 | 0.15 | |
| Tur2-3-6 | 35.43 | 0.16 | 30.13 | 0.03 | 9.82 | 6.99 | 0.19 | 0.04 | 2.53 | 0.05 | 0.02 | |
| Tur2-3-7 | 35.35 | 0.31 | 29.87 | - | 11.03 | 6.66 | 0.20 | 0.04 | 2.48 | 0.06 | 0.06 | |
| Tur2-3-8 | 35.31 | 0.25 | 28.11 | 0.01 | 11.35 | 7.41 | 0.10 | 0.04 | 2.40 | 0.06 | 0.01 | |
| Tur2-3-9 | 35.12 | 0.25 | 28.13 | - | 11.60 | 7.22 | 0.08 | 0.04 | 2.53 | 0.02 | 0.00 | |
| Tur-Ⅲ | Tur1-3-1 | 35.38 | 0.56 | 29.53 | 0.02 | 11.04 | 6.24 | 0.20 | - | 2.36 | 0.07 | 0.08 |
| Tur1-3-12 | 35.04 | 0.09 | 30.78 | 0.02 | 9.34 | 6.95 | 0.19 | 0.02 | 2.42 | 0.04 | - | |
| Tur2-4-1 | 35.39 | 0.86 | 29.44 | - | 10.87 | 6.64 | 0.32 | 0.03 | 2.30 | 0.03 | 0.12 | |
| Tur2-4-2 | 35.97 | 0.72 | 29.44 | - | 10.50 | 6.63 | 0.32 | 0.04 | 2.22 | 0.04 | 0.05 | |
| Tur2-4-3 | 35.48 | 1.17 | 27.99 | - | 12.17 | 6.23 | 0.39 | 0.06 | 2.14 | 0.03 | 0.13 | |
| Tur2-4-4 | 35.31 | 0.20 | 29.58 | 0.01 | 10.52 | 7.14 | 0.16 | 0.07 | 2.27 | 0.02 | - | |
| Tur2-6-4 | 35.30 | 0.16 | 28.84 | - | 11.41 | 7.12 | 0.15 | 0.03 | 2.34 | 0.02 | 0.02 | |
| Tur2-6-6 | 35.45 | 0.18 | 29.05 | 0.00 | 10.27 | 7.55 | 0.12 | 0.07 | 2.39 | 0.04 | 0.02 |
|
表2 西藏达局地区电气石结构式各位置离子数特征Table 2 Characteristics of the number of ions in each position of tourmaline structure in Daju area,Xizang(apfu) |
| 样品编号 | T-site | Z-site | Y-site | X-site | X_Vac | OH+F | B2O3 * | H2O* | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Si4+ | Al3+ | 总和 | Al3+ | Mg2+ | 总和 | Al3+ | Ti4+ | Fe2+ | Mg2+ | Mn2+ | 总和 | Ca2+ | Na+ | K+ | |||||
| Tur1-3-2 | 5.95 | 0.05 | 6.00 | 5.71 | 0.29 | 6.00 | 0.00 | 0.11 | 1.57 | 1.41 | 0.00 | 3.09 | 0.06 | 0.78 | 0.01 | 0.15 | 4 | 10.23 | 3.45 |
| Tur1-3-3 | 5.99 | 0.01 | 6.00 | 5.76 | 0.24 | 6.00 | 0.00 | 0.02 | 1.58 | 1.61 | 0.00 | 3.21 | 0.02 | 0.73 | 0.01 | 0.24 | 4 | 10.23 | 3.53 |
| Tur2-6-1 | 5.95 | 0.05 | 6.00 | 5.90 | 0.10 | 6.00 | 0.00 | 0.03 | 1.52 | 1.55 | 0.00 | 3.10 | 0.04 | 0.80 | 0.01 | 0.15 | 4 | 10.28 | 3.50 |
| Tur2-6-2 | 5.97 | 0.03 | 6.00 | 5.90 | 0.10 | 6.00 | 0.00 | 0.04 | 1.50 | 1.53 | 0.00 | 3.08 | 0.04 | 0.78 | 0.01 | 0.16 | 4 | 10.29 | 3.54 |
| Tur2-6-3 | 5.99 | 0.01 | 6.00 | 5.84 | 0.16 | 6.00 | 0.00 | 0.03 | 1.51 | 1.58 | 0.00 | 3.11 | 0.04 | 0.80 | 0.02 | 0.15 | 4 | 10.33 | 3.54 |
| Tur1-3-4 | 5.97 | 0.03 | 6.00 | 6.00 | 0.00 | 6.00 | 0.03 | 0.02 | 1.38 | 1.62 | 0.00 | 3.05 | 0.03 | 0.76 | 0.01 | 0.19 | 4 | 10.32 | 3.54 |
| Tur1-3-5 | 5.95 | 0.05 | 6.00 | 5.99 | 0.01 | 6.00 | 0.00 | 0.04 | 1.45 | 1.56 | 0.00 | 3.05 | 0.03 | 0.80 | 0.01 | 0.16 | 4 | 10.31 | 3.55 |
| Tur1-3-7 | 5.95 | 0.05 | 6.00 | 5.76 | 0.24 | 6.00 | 0.00 | 0.10 | 1.55 | 1.41 | 0.01 | 3.07 | 0.05 | 0.79 | 0.00 | 0.16 | 4 | 10.29 | 3.45 |
| Tur1-3-11 | 5.94 | 0.06 | 6.00 | 6.00 | 0.00 | 6.00 | 0.10 | 0.03 | 1.26 | 1.62 | 0.00 | 3.01 | 0.04 | 0.78 | 0.01 | 0.17 | 4 | 10.45 | 3.57 |
| Tur2-3-1 | 5.96 | 0.04 | 6.00 | 5.94 | 0.06 | 6.00 | 0.00 | 0.01 | 1.44 | 1.60 | 0.01 | 3.06 | 0.03 | 0.85 | 0.01 | 0.10 | 4 | 10.41 | 3.58 |
| Tur2-3-2 | 5.92 | 0.08 | 6.00 | 5.99 | 0.01 | 6.00 | 0.00 | 0.02 | 1.35 | 1.67 | 0.00 | 3.04 | 0.04 | 0.84 | 0.01 | 0.11 | 4 | 10.46 | 3.58 |
| Tur2-3-3 | 5.95 | 0.05 | 6.00 | 5.94 | 0.06 | 6.00 | 0.00 | 0.03 | 1.41 | 1.63 | 0.00 | 3.08 | 0.04 | 0.82 | 0.01 | 0.13 | 4 | 10.29 | 3.53 |
| Tur2-3-4 | 5.97 | 0.03 | 6.00 | 5.88 | 0.12 | 6.00 | 0.00 | 0.03 | 1.52 | 1.55 | 0.01 | 3.10 | 0.03 | 0.82 | 0.03 | 0.12 | 4 | 10.22 | 3.51 |
| Tur2-3-5 | 6.00 | 0.00 | 6.00 | 5.67 | 0.33 | 6.00 | 0.00 | 0.15 | 1.60 | 1.31 | 0.00 | 3.06 | 0.06 | 0.75 | 0.02 | 0.17 | 4 | 10.25 | 3.47 |
| Tur2-3-6 | 5.96 | 0.04 | 6.00 | 5.92 | 0.08 | 6.00 | 0.00 | 0.02 | 1.38 | 1.68 | 0.01 | 3.08 | 0.03 | 0.82 | 0.01 | 0.13 | 4 | 10.34 | 3.56 |
| Tur2-3-7 | 5.94 | 0.06 | 6.00 | 5.86 | 0.14 | 6.00 | 0.00 | 0.04 | 1.55 | 1.52 | 0.01 | 3.12 | 0.04 | 0.81 | 0.01 | 0.14 | 4 | 10.34 | 3.54 |
| Tur2-3-8 | 6.02 | 0.00 | 6.02 | 5.65 | 0.35 | 6.00 | 0.00 | 0.03 | 1.62 | 1.53 | 0.01 | 3.18 | 0.02 | 0.79 | 0.01 | 0.18 | 4 | 10.19 | 3.51 |
| Tur2-3-9 | 6.00 | 0.00 | 6.00 | 5.66 | 0.34 | 6.00 | 0.00 | 0.03 | 1.66 | 1.50 | 0.01 | 3.20 | 0.01 | 0.84 | 0.00 | 0.14 | 4 | 10.17 | 3.51 |
| Tur1-3-1 | 5.98 | 0.02 | 6.00 | 5.87 | 0.13 | 6.00 | 0.00 | 0.07 | 1.56 | 1.44 | 0.00 | 3.07 | 0.04 | 0.77 | 0.02 | 0.17 | 4 | 10.28 | 3.51 |
| Tur1-3-12 | 5.90 | 0.10 | 6.00 | 6.00 | 0.00 | 6.00 | 0.02 | 0.01 | 1.32 | 1.74 | 0.00 | 3.09 | 0.03 | 0.79 | 0.01 | 0.16 | 4 | 10.32 | 3.56 |
| Tur2-4-1 | 5.95 | 0.05 | 6.00 | 5.78 | 0.22 | 6.00 | 0.00 | 0.11 | 1.53 | 1.45 | 0.00 | 3.09 | 0.06 | 0.75 | 0.01 | 0.19 | 4 | 10.34 | 3.51 |
| Tur2-4-2 | 6.03 | 0.00 | 6.03 | 5.81 | 0.19 | 6.00 | 0.00 | 0.09 | 1.47 | 1.47 | 0.00 | 3.03 | 0.06 | 0.72 | 0.01 | 0.22 | 4 | 10.38 | 3.56 |
| Tur2-4-3 | 6.03 | 0.00 | 6.03 | 5.60 | 0.40 | 6.00 | 0.00 | 0.15 | 1.73 | 1.18 | 0.01 | 3.07 | 0.07 | 0.71 | 0.01 | 0.22 | 4 | 10.23 | 3.47 |
| Tur2-4-4 | 5.96 | 0.04 | 6.00 | 5.85 | 0.15 | 6.00 | 0.00 | 0.03 | 1.49 | 1.64 | 0.01 | 3.16 | 0.03 | 0.74 | 0.00 | 0.22 | 4 | 10.29 | 3.55 |
| Tur2-6-4 | 5.99 | 0.01 | 6.00 | 5.75 | 0.25 | 6.00 | 0.00 | 0.02 | 1.62 | 1.55 | 0.00 | 3.20 | 0.03 | 0.77 | 0.00 | 0.20 | 4 | 10.25 | 3.52 |
| Tur2-6-6 | 5.99 | 0.01 | 6.00 | 5.78 | 0.22 | 6.00 | 0.00 | 0.02 | 1.45 | 1.69 | 0.01 | 3.17 | 0.02 | 0.78 | 0.01 | 0.19 | 4 | 10.28 | 3.54 |
|
图5 西藏达局地区电气石分类图解(a)达局地区电气石X位置占位情况的分类图解(底图据Henry et al,2011);(b)达局地区电气石Al-Fe-Mg原岩判别图解(底图据Henry et al,1985);(c)Mg/(Mg+Fe)-Na/(Na+Ca)分类图;(d)Mg/(Mg+Fe)-X/(X+Na+K)分类图;区域1~8代表电气石可能的形成环境:1-富Li的花岗岩和伟晶岩、细晶岩;2-贫Li的花岗岩和伟晶岩、细晶岩;3-富Fe3+的石英—电气石岩(热液蚀变花岗岩);4-含Al饱和矿物的变质泥质岩和变质砂屑岩;5-不含Al饱和矿物的变质泥质岩和变质砂屑岩;6-富Fe3+石英—电气石岩、钙硅酸盐和变质沉积岩;7-贫Ca的变质超镁铁质岩和富Cr、V的变质泥质岩;8-变质碳酸盐岩和变质辉石岩(据Henry et al,1985) Fig. 5 Classification diagrams of tourmaline in Daju area,Xizang |
3.2 微量元素
表3 西藏达局地区电气石微量元素分析结果Table 3 Analysis results of trace elements of tourmaline in Daju area,Xizang(×10-6) |
| 样品类型 | 样品编号 | Li | Sc | V | Ni | Cu | Zn | Ga | As | Sr | Zr | Nb | Sn | Pb | Th | U |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tur-Ⅰ | Tur1-3-2 | - | 20.7 | 226 | 41.5 | 8.2 | 174 | 43.3 | - | 1 104 | 0.3 | 0.4 | 5.8 | 18.0 | 1.4 | 0 |
| Tur1-3-3 | - | 6.7 | 218 | 22.9 | 33.6 | 266 | 52.5 | 10.3 | 1 373 | 0.9 | 0.4 | 9.1 | 29.4 | 4.1 | 0.1 | |
| Tur2-6-1 | - | 48.5 | 322 | 72.7 | 6.2 | 144 | 63.0 | 5.5 | 1 088 | 1.3 | 1.1 | 16.5 | 21.0 | 1.0 | 0 | |
| Tur2-6-2 | - | 23.6 | 328 | 84.7 | 5.3 | 165 | 57.9 | - | 1 727 | 0.4 | 0.5 | 9.9 | 22.5 | 1.0 | - | |
| Tur2-6-3 | - | 67.4 | 338 | 77.8 | 7.9 | 140 | 61.3 | 6.1 | 1 245 | 1.3 | 1.8 | 17.5 | 24.9 | 2.9 | 0 | |
| Tur-Ⅱ | Tur1-3-4 | - | 16.9 | 190 | 108.0 | 2.2 | 201 | 44.3 | - | 1 943 | 0.3 | 0.5 | 3.2 | 35.0 | 0.1 | 0 |
| Tur1-3-5 | - | 19.7 | 292 | 67.7 | 7.2 | 200 | 65.5 | 3.0 | 1 284 | 0.2 | 0.1 | 9.8 | 24.3 | 1.3 | 0 | |
| Tur1-3-7 | - | 124.0 | 223 | 92.7 | 5.9 | 162 | 44.5 | 2.3 | 1 143 | 0.6 | 0.5 | 9.7 | 25.1 | 1.7 | 0 | |
| Tur1-3-11 | 12.2 | 24.7 | 308 | 79.4 | 97.3 | 293 | 69.9 | 55.4 | 1 116 | 4.9 | 1.4 | 15.1 | 31.4 | 6.5 | 0.9 | |
| Tur2-3-1 | 7.9 | 10.4 | 246 | 34.3 | 15.3 | 156 | 53.3 | 11.9 | 1 048 | 0.8 | 0.3 | 15.0 | 16.0 | 2.0 | 0.1 | |
| Tur2-3-2 | 9.3 | 10.1 | 260 | 45.3 | 34.9 | 178 | 59.0 | 31.6 | 1 072 | 0.1 | 0.5 | 12.6 | 22.5 | 5.4 | 0.3 | |
| Tur2-3-3 | 8.3 | 16.3 | 247 | 90.8 | 7.2 | 238 | 52.6 | 5.2 | 1 782 | 0.2 | 0.9 | 9.1 | 31.3 | 0.7 | 0 | |
| Tur2-3-4 | 8.8 | 20.0 | 254 | 59.1 | 9.7 | 191 | 59.9 | 5.9 | 1 094 | 0.3 | 0.7 | 14.5 | 21.7 | 0.5 | 0 | |
| Tur2-3-5 | 7.2 | 6.4 | 156 | 36.4 | 24.5 | 118 | 36.9 | 24.9 | 589 | 0.2 | 0.1 | 6.5 | 18.0 | 3.8 | 0.2 | |
| Tur2-3-6 | 8.5 | 44.9 | 250 | 60.8 | 10.9 | 176 | 64.1 | 18.3 | 1 228 | 0.3 | 0.1 | 12.0 | 18.4 | 2.4 | 0.3 | |
| Tur2-3-7 | 9.5 | 41.6 | 270 | 60.5 | 12.5 | 196 | 70.0 | 22.7 | 1 239 | 0.8 | 0.3 | 15.7 | 23.6 | 4.0 | 0.3 | |
| Tur2-3-8 | 7.7 | 20.1 | 219 | 48.3 | 19.1 | 181 | 51.7 | 25.2 | 813 | 0.6 | 0.2 | 9.1 | 13.5 | 1.5 | 0.3 | |
| Tur2-3-9 | - | 35.8 | 189 | 22.0 | 25.8 | 143 | 46.3 | 26.7 | 802 | 1.1 | 0.2 | 13.1 | 12.8 | 2.9 | 0.3 | |
| Tur-Ⅲ | Tur1-3-1 | - | 33.9 | 205 | 21.2 | 22.1 | 106 | 55.7 | 14.8 | 1 284 | 24.4 | 15.4 | 16.4 | 29.3 | 4.3 | 0.2 |
| Tur1-3-12 | - | 92.0 | 272 | 187.0 | 1 770 | 824 | 54.7 | 1 501 | 830 | 3.0 | 1.2 | 5.8 | 144.0 | 165.0 | 19.1 | |
| Tur2-4-1 | 7.1 | 4.0 | 195 | 52.2 | 34.9 | 191 | 43.8 | 4.5 | 1 221 | 0.8 | 0.2 | 6.0 | 18.6 | 0.6 | 0 | |
| Tur2-4-2 | 6.1 | 2.9 | 154 | 47.6 | 18.9 | 139 | 36.5 | 2.8 | 1 097 | 1.3 | 0.2 | 2.9 | 18.0 | 0.4 | 0.1 | |
| Tur2-4-3 | 8.9 | 6.6 | 239 | 41.4 | 66.4 | 186 | 52.5 | 5.5 | 907 | 0.5 | 0.4 | 5.9 | 19.2 | 1.3 | 0 | |
| Tur2-4-4 | 9.2 | 4.4 | 178 | 60.4 | 53.8 | 172 | 43.0 | 3.4 | 1 346 | 2.0 | 0.5 | 3.0 | 28.0 | 2.5 | 0.1 | |
| Tur2-6-4 | - | 23.7 | 360 | 66.8 | 10.3 | 139 | 56.0 | 5.6 | 1 130 | 0.4 | 0.2 | 12.9 | 14.4 | 1.3 | 0 | |
| Tur2-6-6 | - | 33.0 | 371 | 57.7 | 12.3 | 147 | 64.5 | 8.4 | 1 080 | 0.5 | 0.3 | 16.1 | 14.6 | 2.2 | - |
|
4 讨论
4.1 电气石成因
图8 西藏达局地区电气石成因判别图解(修改自Sciuba et al,2021)(a)Sr-V协变图;(b)Nb-V协变图;朱诺地区数据来自Zheng et al(2024);吉隆地区数据来自Pei et al(2023);错那地区数据来自Xie et al(2023a) Fig. 8 Discrimination diagrams of tourmaline genesis in Daju area,Xizang(modified after Sciuba et al,2021) |
4.2 电气石类型
图9 西藏达局地区电气石矿床类型判别图解(底图据Beckett-Brown et al,2023a)朱诺地区数据来自Zheng et al(2024);吉隆地区数据来自Pei et al(2023);错那地区数据来自Xie et al(2023a) Fig. 9 Discrimination diagram of tourmaline deposit type in Daju area,Xizang(base map after Beckett-Brown et al,2023a) |
4.3 找矿指示意义
图10 西藏达局地区电气石Fe-Mg-Al三元图解(修改自Baksheev et al,2012)Fig. 10 Fe-Mg-Al ternary diagram of tourmaline in Daju area,Xizang(modified after Baksheev et al,2012) |
图11 西藏达局地区电气石球粒陨石稀土元素配分模式图和电气石微量元素蛛网图(a)电气石球粒陨石稀土元素配分模式图;(b)电气石微量元素蛛网图;球粒陨石原始数据来自Boynton(1984),原始地幔数据来自Sun et al(1989);朱诺地区数据来自Zheng et al(2024);吉隆地区数据来自Pei et al(2023);错那地区数据来自Xie et al(2023a) Fig. 11 Rare earth elements distribution pattern diagram of tourmaline chondrites and trace elements spider diagram of tourmaline in Daju area,Xizang |
图12 不同地区电气石微量元素图解(a)Ta-Ba协变图;(b)Sr/Y-Rb协变图;(c)Nb-Ni协变图;(d)Co-Ni协变图;朱诺地区数据来自Zheng et al(2024);吉隆地区数据来自Pei et al(2023);错那地区数据来自Xie et al(2023a) Fig. 12 Diagrams of trace elements of tourmaline in different regions |

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