西藏甲玛矿区侵入岩成岩成矿年龄
The Diagenesis and Metallogenesis Age of the Intrusive Rock in Jiama Deposit in Tibet

摘要： 摘要：西藏甲玛铜多金属矿床位于冈底斯成矿带东段，属于超大型斑岩-矽卡岩型矿床，具有巨大的成矿潜力。铜多金属矿床的成矿作用主要受控于NS向正断层及其受断裂控制的具有埃达克岩地球化学特征的中酸性斑岩体。利用锆石LAICPMS UPb测年方法对矿区含矿与不含矿的中酸性斑岩脉进行了年龄测定，3件样品的岩浆锆石UPb年龄为14~16 Ma，表明甲玛铜多金属矿床及矿区与成矿有关的岩脉均形成于中新世早期；利用ESR测年方法，获得含矿石英脉年龄139~164 Ma，含矿方解石脉年龄5~7 Ma，测年结果表明甲玛矿区主要成岩成矿作用同期，形成于中新世早期，并在中新世晚期受构造运动影响仍然存在较弱的成矿作用。
Abstract: Abstract: The Jiama coppermultimetal deposit in Tibet lies in the eastern part of the Gangdisi metallogenic belt. It belongs to superlarge porphyryskarn type deposit and has great potential for mineralization. The mineralization in the mining area is controlled by the NS normal fault, which offer the space for metallic element enrichment and magmatic hydrothermal rise. In this paper, LAICPMS zircon UPb dating was used to study the porphyry and skarn age. The dating results show that the diagenesis and mineralization age of the mining area is 14-16 Ma, and the ESR dating results show that the quartz veins age is 139-164 Ma, the calcite veins age is 5-7 Ma. The dating results show that the diagenesis and the metallogenesis are both in the Miocene period, in the later period, there are still weak metallogenesis in Jiama deposit influenced by tectonic movement