1 区域地质背景
图1 土堆—沙旺金矿床大地构造位置图(a)和区域地质简图(b)(修改自李国华等,2016;薄军委等,2021)Ⅰ-华北板块;Ⅰ1-胶莱—胶北断隆;Ⅰ -胶北断隆;Ⅰ -胶莱断陷;Ⅱ-秦岭—大别—苏鲁碰撞造山带;Ⅱ1-胶南—威海断隆;Ⅱ -文登—威海断拱;Ⅱ -胶莱断陷;Ⅱ -胶南—临沭断拱;1.湖泊;2.第四系;3.下白垩统莱阳群和青山群陆相沉积岩;4.古元古界荆山群变质岩;5.前寒武纪花岗质片麻岩;6.晚侏罗世二长花岗岩;7.早白垩世花岗闪长岩;8.燕山晚期脉岩;9.地质界线;10.断裂;11.韧性剪切带;12.金矿床(点);13.钼矿床;14.铜矿点;15.铅锌矿点;16.胶莱盆地东北缘地区位置 Fig.1 Tectonic location map(a) and regional geological map(b)of the Tudui-Shawang gold deposit(modified after Li et al.,2016;Bo et al.,2021) |
2 矿区及矿床地质特征
图2 土堆—沙旺金矿床矿区地质图(a)(修改自杨春福,2010)和沙旺金矿区勘探线联合剖面图(b)(修改自Liu et al.,2021)1.莱阳群;2.荆山群;3.二长花岗岩;4.中生代脉岩;5.断裂;6.矿体;7.采样点 Fig.2 Geological map of the Tudui-Shawang gold deposit(a)(modified after Yang,2010) and joint profile of the exploration line in Shawang gold mining area(b)(modified after Liu et al.,2021) |
图3 土堆—沙旺金矿床矿石和围岩蚀变及矿化特征(a)二长花岗岩;(b)二长花岗岩,4×10(+)薄片;(c)钾化、绿泥石化矿石;(d)黄铁矿化二长花岗岩,4×10(+)光薄片;(e)二长花岗岩中黄铁矿,4×10(-)光薄片;(f)浸染状金属硫化物金矿石;(g)石英—细粒黄铁矿金矿石;(h)黄铁矿化(阶段Ⅰ);(i)早阶段(阶段Ⅰ)的自形晶粒状黄铁矿,4×10(-)光片;(j)绢云母化和硅化(阶段Ⅱ),4×10(+)薄片;(k)自然金包裹于黄铁矿颗粒中(阶段Ⅱ),4×20(-)光片;(l)闪锌矿交代黄铁矿(阶段Ⅱ),4×10(-)光片;Qtz-石英;Pl-斜长石;Kfs-钾长石;Chl-绿泥石;Bt-黑云母;Hbl-角闪石;Ser-绢云母;Py-黄铁矿;Sp-闪锌矿;Gn-方铅矿;Gl-自然金 Fig.3 Alteration and mineralization characteristics of the ore and altered wall-rocks in the Tudui-Shawang gold deposit |
3 样品描述与分析测试方法
3.1 样品描述
3.2 分析测试方法
4 分析测试结果
4.1 S、Pb同位素
表1 土堆—沙旺金矿床S、Pb同位素测试结果Table 1 Sulfur and lead isotope test results of Tudui-Shawang gold deposit |
| 样品编号 | 采样坐标 | 矿物名称 | δ 34S/‰ | 206Pb/204Pb | 207Pb/204Pb | 208Pb/204Pb | Th/U | Δβ | Δγ |
|---|---|---|---|---|---|---|---|---|---|
| 2TD-5-1 | 120°09′43″ E,37°03'42″ N | 黄铁矿 | -0.8 | 18.147 | 15.520 | 38.276 | 3.79 | 13.24 | 32.74 |
| 2TD-5-2 | 120°09'42″ E,37°03'42″ N | 黄铁矿 | -1.6 | 18.256 | 15.537 | 38.326 | 3.75 | 14.08 | 31.50 |
| 2TD-8-1 | 120°09'32″ E,37°03'35″ N | 黄铁矿 | 2.2 | 18.330 | 15.496 | 38.423 | 3.75 | 10.95 | 29.45 |
| 2TD-8-2 | 120°09'42″ E,37°03'33″ N | 黄铁矿 | 0.9 | 18.262 | 15.526 | 38.296 | 3.74 | 13.28 | 29.90 |
| 2TD-8-3 | 120°09'42″ E,37°03'38″ N | 黄铁矿 | 1.3 | 18.191 | 15.589 | 38.394 | 3.83 | 18.00 | 38.22 |
| 2TD-9-1 | 120°09'42″ E,37°03'40″ N | 闪锌矿 | -1.5 | 18.347 | 15.576 | 38.413 | 3.75 | 16.54 | 33.05 |
| 2TD-9-2 | 120°09'42″ E,37°03'41″ N | 闪锌矿 | -1.1 | 18.245 | 15.535 | 38.366 | 3.78 | 13.98 | 32.84 |
| 2TD-9-3 | 120°09'41″ E,37°03'39″ N | 闪锌矿 | 0.7 | 18.190 | 15.571 | 38.247 | 3.76 | 16.72 | 33.32 |
| 2YT-1-1 | 120°09'43″ E,37°03'51″ N | 二长花岗岩 | 18.244 | 15.486 | 38.356 | 3.76 | 10.51 | 29.86 | |
| 2YT-1-2 | 120°09'45″ E,37°03'35″ N | 二长花岗岩 | 18.350 | 15.557 | 38.259 | 3.68 | 15.19 | 27.78 | |
| 2YT-1-3 | 120°09'42″ E,37°03'41″ N | 二长花岗岩 | 18.259 | 15.550 | 38.363 | 3.77 | 14.99 | 33.11 |
4.2 锆石LA-ICP-MS U-Pb同位素测年
图4 土堆—沙旺金矿床二长花岗岩锆石阴极发光图像Fig.4 CL image of zircon from monzogranite in the Tudui-Shawang gold deposit |
表2 土堆—沙旺金矿床二长花岗岩锆石LA-ICP-MS U-Pb同位素分析结果Table 2 Zircon LA-ICP-MS U-Pb isotope analysis results of monzogranite in the Tudui-Shawang gold deposit |
| 样品编号 | Th/(×10-6) | U/(×10-6) | Th /U | 同位素比值 | 年龄/Ma | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 207Pb /206Pb | 1σ | 207Pb /235U | 1σ | 206Pb /238U | 1σ | 208Pb /232Th | 1σ | 207Pb /206Pb | 1σ | 207Pb /235U | 1σ | 206Pb /238U | 1σ | 208Pb /232Th | 1σ | ||||
| 28SW-1-1 | 548.5 | 762.7 | 0.7 | 0.05082 | 0.00335 | 0.12748 | 0.00828 | 0.01820 | 0.00032 | 0.00630 | 0.00048 | 233 | 116 | 122 | 7 | 116 | 2 | 127 | 10 |
| 28SW-1-2 | 382.0 | 643.6 | 0.6 | 0.05114 | 0.00357 | 0.13093 | 0.00902 | 0.01858 | 0.00033 | 0.00569 | 0.00048 | 247 | 125 | 125 | 8 | 119 | 2 | 115 | 10 |
| 28SW-1-3 | 396.9 | 963.2 | 0.4 | 0.04785 | 0.00300 | 0.11935 | 0.00738 | 0.01810 | 0.00031 | 0.00602 | 0.00038 | 92 | 105 | 114 | 7 | 116 | 2 | 121 | 8 |
| 28SW-1-4 | 353.0 | 947.1 | 0.4 | 0.05626 | 0.00396 | 0.13816 | 0.00955 | 0.01782 | 0.00034 | 0.00600 | 0.00043 | 463 | 120 | 131 | 9 | 114 | 2 | 121 | 9 |
| 28SW-1-5 | 389.6 | 1 244.5 | 0.3 | 0.04802 | 0.00229 | 0.12276 | 0.00579 | 0.01855 | 0.00028 | 0.00654 | 0.00023 | 100 | 78 | 118 | 5 | 118 | 2 | 132 | 5 |
| 28SW-1-6 | 622.0 | 1 147.7 | 0.5 | 0.04634 | 0.00220 | 0.12200 | 0.00575 | 0.01910 | 0.00029 | 0.00701 | 0.00033 | 15 | 72 | 117 | 5 | 122 | 2 | 141 | 7 |
| 28SW-1-7 | 588.5 | 950.0 | 0.6 | 0.04927 | 0.00324 | 0.12429 | 0.00806 | 0.01831 | 0.00032 | 0.00606 | 0.00035 | 161 | 114 | 119 | 7 | 117 | 2 | 122 | 7 |
| 28SW-1-8 | 285.5 | 564.7 | 0.5 | 0.04936 | 0.00316 | 0.11927 | 0.00752 | 0.01753 | 0.00030 | 0.00555 | 0.00024 | 165 | 112 | 114 | 7 | 112 | 2 | 112 | 5 |
| 28SW-1-9 | 517.3 | 735.5 | 0.7 | 0.05192 | 0.00235 | 0.13067 | 0.00587 | 0.01826 | 0.00028 | 0.00578 | 0.00016 | 282 | 75 | 125 | 5 | 117 | 2 | 116 | 3 |
| 28SW-1-10 | 359.5 | 841.7 | 0.4 | 0.04990 | 0.00203 | 0.12334 | 0.00497 | 0.01793 | 0.00026 | 0.00589 | 0.00017 | 190 | 67 | 118 | 4 | 115 | 2 | 119 | 3 |
| 28SW-1-11 | 641.6 | 1 083.3 | 0.6 | 0.04394 | 0.00306 | 0.10932 | 0.00752 | 0.01805 | 0.00032 | 0.00565 | 0.00019 | -74 | 116 | 105 | 7 | 115 | 2 | 114 | 4 |
| 28SW-1-12 | 477.2 | 782.9 | 0.6 | 0.04997 | 0.00219 | 0.13205 | 0.00572 | 0.01917 | 0.00029 | 0.00661 | 0.00019 | 194 | 72 | 126 | 5 | 122 | 2 | 133 | 4 |
| 28SW-1-13 | 595.5 | 983.8 | 0.6 | 0.04941 | 0.00221 | 0.11918 | 0.00528 | 0.01750 | 0.00026 | 0.00544 | 0.00014 | 167 | 76 | 114 | 5 | 112 | 2 | 110 | 3 |
| 28SW-1-14 | 765.6 | 1 269.7 | 0.6 | 0.04520 | 0.00323 | 0.11042 | 0.00777 | 0.01772 | 0.00032 | 0.00638 | 0.00082 | -9 | 118 | 106 | 7 | 113 | 2 | 129 | 16 |
| 28SW-1-15 | 574.9 | 959.0 | 0.6 | 0.04948 | 0.00218 | 0.12275 | 0.00535 | 0.01800 | 0.00027 | 0.00579 | 0.00026 | 171 | 74 | 118 | 5 | 115 | 2 | 117 | 5 |
| 28SW-1-16 | 419.0 | 964.0 | 0.4 | 0.05096 | 0.00164 | 0.12275 | 0.00394 | 0.01747 | 0.00024 | 0.00568 | 0.00014 | 239 | 49 | 118 | 4 | 112 | 2 | 114 | 3 |
| 28SW-1-17 | 548.5 | 762.7 | 0.7 | 0.04559 | 0.00291 | 0.11554 | 0.00728 | 0.01839 | 0.00032 | 0.00614 | 0.00031 | -24 | 103 | 111 | 7 | 117 | 2 | 124 | 6 |
5 讨论
5.1 成矿物质来源
图6 土堆—沙旺金矿床S、Pb同位素示踪图解(a)土堆—沙旺金矿床S同位素组成(Ohmoto,1972);(b、c)Pb同位素构造模式图(Zartman et al.,1981);(d)Pb同位素Δβ-Δγ成因分类图解(朱炳泉,1998);1-地幔源铅;2-上地壳铅;3-上地壳与地幔混合的俯冲带铅;5-海底热水作用铅;6-中深作用变质铅;7-深变质下地壳铅;8-造山带铅;9-古老页岩上地壳铅;10-退变质铅 Fig.6 S and Pb isotope tracing diagram of the Tudui-Shawang gold deposit |
5.2 成矿时代
表3 胶莱盆地东北缘区内金矿床成矿年代对比Table 3 Comparison of metallogenic age of gold deposits in the northeastern margin of the Jiao-Lai Basin |
| 矿床名称 | 岩性 | 测试矿物(岩石) | 年龄/Ma | 测试方法 | 参考文献 |
|---|---|---|---|---|---|
| 辽上金矿床 | 碳酸盐脉型矿石 | 黄铁矿 | 117.9±2.4 | Rb-Sr | 丁正江等,2021 |
| 前垂柳金矿床 | 碳酸盐脉黄铁矿化花岗质碎裂岩 | 黄铁矿 | 123.8±5.0 | Rb-Sr | 韩小梦等,2024 |
| 西涝口金矿床 | 成矿期煌斑岩 | 锆石 | 118.6±1.5 | LA-ICP-MS | 周晓萍等,2022b |
| 蓬家夼金矿床 | 成矿期前粗粒闪长岩 | 锆石 | 122.9±3.0 | LA-ICP-MS | 孙丽伟,2015 |
| 蓬家夼金矿床 | 成矿期前细粒闪长岩 | 锆石 | 123.9±3.8 | LA-ICP-MS | 孙丽伟,2015 |
| 发云夼金矿床 | 矿石黄铁矿 | 黄铁矿 | 128±7 | Rb-Sr | 张连昌等,2002 |
| 唐家沟金矿床 | 蚀变岩 | 锆石、独居石 | 121.5±2.7 | LA-ICP-MS | 唐文龙等,2021 |
| 邓格庄金矿床 | 二长花岗岩 | 钾长石 | 123±0.5 | Ar-Ar | 薛建玲等,2019 |

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