【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SiO₂（75.50%⁷6.14%）、K₂O（4.38%⁵.19%）,贫Al₂O₃（12.25%¹3.08%）、Ba(26.6×10^-6164×10^-6)、Sr(4.74×10^-646.0×10^-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0.44⁰.80,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;170²30Ma为该区构造活动的平静期;进入侏罗纪-早白垩世（120¹70Ma）,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认识。更多还原

【Abstract】 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 SiO₂ content（ 66. 81% 77. 39%）,K₂O content（ 4. 38% 5. 19%）,poor Al₂O₃ 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 orogenic environment. According to the chronological research of Hongling ore district and the main intrusive rocks of its peripheral region,combining with the geological characters and previous research results,we summarize the tectonic evolution history of the southern part of Da Xing’an Mountains polymetallic ore belt as follows: The bilateral subduction of Paleo-asian ocean may evolve to Late Carboniferous period; collisional collapse process occurred since Permian; the series of tectonic magmatic events of Permian epoch-Middle Triassic may closely connected with the crust-thickening and crust-delaminating after collisional orogeny and it marks the ending of evolution of Central Asian Orogenic Belt; 170 230 Ma for the quiet period of the tectonic activities; it became the component of Mongolia-Okhotsk tectonic domain during Late Jurassic epoch-Early Jurassic epoch（ 120 ¹70Ma）; and ages less than 120 Ma of rock mass in this area are scarcely reported. Accordingly,we hold the opinion that this area is not strongly affected by the Pacific tectonic system,and draw the conclusion that the continental dynamics background of Hongling PbZn deposit is continental crust extensional environment after the collision orogenic of Mongolia-Okhotsk orogenic belt.更多还原