大兴安岭南段红岭铅锌矿床岩浆演化序列与成矿动力学背景探讨  

Discussion on the magmatic evolution sequence and metallogenic geodynamical setting background Hongling Pb-Zn deposit in the southern Da Xing'an Mountains

作　　者：李剑锋[1,2] 王可勇[2,3] 权鸿雁[2] 孙丰月[2] 赵来时[3] 张雪冰[2] 

机构地区：[1]辽宁师范大学城市与环境学院,大连116029 [2]吉林大学地球科学学院,长春130061 [3]中国地质大学地质过程与矿产资源国家重点实验室,武汉430074

出　　处：《岩石学报》2016年第5期1529-1542,共14页Acta Petrologica Sinica

基　　金：中国地质大学地质过程与矿产资源国家重点实验室开放课题基金(GPMR201307);辽宁师范大学校青年基金(LS2015L016)联合资助

摘　　要：红岭是内蒙古东部地区的一处大型铅锌多金属矿床。矿体产于燕山晚期花岗岩与二叠系大石寨组的外接触带上,受NE向断裂控制。本文对红岭矿区及其外围主要岩浆岩开展了年代学研究,系统的LA-ICP-MS锆石定年结果表明:红岭矿区与矿化关系密切的乌兰坝岩体中浅褐黄色花岗斑岩、中粗粒花岗岩、灰褐色斑状花岗岩及深部钻孔揭露的细粒花岗岩测试结果分别为136.70±0.85Ma、144.1±1.5Ma、139.7±1.1Ma和144.82±0.81Ma,显示出由多阶段岩浆侵入形成的复式岩体的特征;乌兰楚鲁特岩体中浅褐灰色斑状花岗岩、含斑细粒花岗岩测年结果为141.9±1.2Ma、139.83±0.82Ma。根据锆石UPb测年的结果,得出两个岩体为同一次构造岩浆事件的产物的结论。岩石地球化学分析表明区内花岗岩类富SiO_2(75.50%~76.14%)、K_2O(4.38%~5.19%),贫Al_2O_3(12.25%~13.08%)、Ba(26.6×10^(-6)~164×10^(-6))、Sr(4.74×10^(-6)~46.0×10^(-6)),稀土元素配分曲线呈右倾轻稀土富集型,具明显铕负异常,δEu值为0.44~0.80,富集高场强元素Zr、Hf和大离子亲石元素Rb、U、Th,显示A型花岗岩地球化学属性,表明其形成于伸展构造体系的造山后环境。本文根据对矿区及外围侵入岩年代学研究,结合矿区地质和前人研究成果,将大兴安岭南段多金属成矿带构造演化史概括为:古亚洲洋双向俯冲可能延续到晚石炭世;约从二叠纪开始,该区进入了碰撞造山阶段;中三叠世-二叠纪的构造岩浆事件与碰撞造山后陆壳加厚和拆沉作用有关,同时标志着中亚造山带演化的终止;170~230Ma为该区构造活动的平静期;进入侏罗纪-早白垩世(120~170Ma),该区受到蒙古-鄂霍次克构造体系活动的远程影响;120Ma~今,鲜有关于岩体年龄的报道,据此我们认为该区域并未受到太平洋构造体系的强烈影响;并得出红岭铅锌矿的成矿动力学背景为蒙古-鄂霍茨克造山带碰撞造山后陆壳伸展环境的�Hongling Pb-Zn deposit is a large scale polymetallic deposit which is located in the eastern Inner Mongolia. The ore bodies mainly occur in the outer contacting belt of the Late Yanshan granite and Permian Dashizhai Formation,controlled by NE strike faults. We have carried out chronological research in allusion to Hongling ore district and the main intrusive rocks of its peripheral region. Zircon LA-ICP-MS U-Pb dating results indicate that the age of Wulanba rock mass include shallow isabelline granite porphyry,flesh red medium coarse-grained granite,taupe porphyritic granite and deep drilling exposed the shallow flesh red fine grained granite is136. 70 ± 0. 85 Ma,144. 1 ± 1. 5Ma,139. 7 ± 1. 1Ma and 144. 82 ± 0. 81 Ma,which is closely related with mineralization in the area of Hongling ore district,its attributes are determined to be the product of Late Jurassic magmatic activity. The age of Wulanchulute finegrained granite is 141. 9 ± 1. 2Ma and medium coarse-grained granite age is 139. 83 ± 0. 82 Ma,they are products of Early Cretaceous and Late Jurassic magmatic activities,which show that Wulanba granite is a composite body formed by multiperiodic magmatic activities. On the basis of dating results we came to the conclusion that the two rock masses are products of the same tectonic magmatic event,they also limited the age of formation of Hongling Pb-Zn deposit. Geochemistry of rock analysis about granite in the study area showed SiO_2 content（ 66. 81% ~ 77. 39%）,K_2O content（ 4. 38% ~ 5. 19%）,poor Al_2O_3 and content（ 11. 33% ~ 14. 54%）,Ba content（ 26. 6 × 10^（-6）~ 164 × 10^（-6））,Sr content（ 4. 74 × 10^（-6）~ 46. 0 × 10^（-6））. The chondrite-normalized REE pattern shows LREE enrichment,strong negative Eu anomalies,and δEu at 0. 44 to 0. 80. The high field strength elements such as Zr,Hf and lithophile elements such as Rb,U and Th are enriched. These features are alkaline granite geochemistry attribute,and it might be formed in the extension structure system of after

关 键 词：红岭铅锌矿床 岩浆岩序列 动力学背景 大兴安岭南段 

分 类 号：P618.41[天文地球—矿床学]