大兴安岭得尔布干成矿带金矿床类型及成矿规律

    TYPES AND METALLOGENIC REGULARITY OF GOLD DEPOSITS IN DERBUGAN METALLOGENIC BELT, DAXINGANLING MOUNTAINS

    • 摘要: 得尔布干成矿带位于蒙古-兴安造山带的东段, 处于额尔齐斯-佐伦-黑河缝合带与蒙古-鄂霍次克缝合带之间. 得尔布干地区受燕山期构造活动影响, 岩浆侵入活动强烈, 并伴有强烈的金成矿作用. 通过对砂宝斯、下吉宝沟、小伊诺盖沟金矿床等典型矿床研究, 分析金矿床成矿地质特征及其产出的构造背景, 划分出以砂岩为容矿岩石的中低温热液蚀变岩型、以火山岩为容矿岩石的浅成低温热液型、与中深成侵入杂岩有关的岩浆热液蚀变岩型、产于韧性剪切带中的构造-热液蚀变岩型等4种矿床类型. 不同类型金矿床的成矿时间主要集中于燕山期晚侏罗世-早白垩世. 根据H-O-Pb同位素研究结果, 成矿热液主要为岩浆水和大气降水的混合水, 成矿物质来自幔源岩浆, 并混染了少量的地壳物质. 不同类型金矿床具有一定的内在成因联系, 属于同一岩浆源区不同阶段岩浆演化的产物. 区域内有色、贵金属内生矿床的成矿在空间展布上具有“北东成带、北西呈行”的特点.

       

      Abstract: The Derbugan metallogenic belt is located in the eastern Mongolia-Xing'an orogenic belt, between the Ertix-Zuolun-Heihe suture zone and Mongolia-Okhotsk suture zone. Affected by Yanshanian movement, magmatic intrusion is heavy in the area, accompanied by intense gold mineralization in Derbugan area. Through the study of Shabaosi, Xiajibaogou and Xiaoyinuogaigou gold deposits, the paper analyzes the metallogenic characteristics and tectonic background of the gold deposits. The deposits can be classified into four types, including epi-mesothermal altered rock type hosted by sandstone, epithermal type hosted by volcanic rock, magmatic hydrothermal altered rock type related to deep intrusive complex, and tectonic-hydrothermal altered rock type occurred in ductile shear zone. The mineralization time of different types of gold deposits is concentrated mainly in Late Jurassic-Early Cretaceous of Yanshanian. According to the H-O-Pb isotope results, the ore-forming hydrothermal fluid is mainly the mixtures of magmatic water and atmospheric precipitation, with the metallogenic material from mantle-derived magma, mixed with minor crustal material. Different types of gold deposits have certain internal genetic relations and belong to the product of magmatic evolution at various stages in the same magmatic source region. The metallogenesis of the endogenetic deposits of nonferrous and precious metals in the region is characteristically distributed at the intersections of a series of parallel NE-trending structural belts and NW-trending secondary structures.

       

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