西藏朱诺斑岩铜矿石英闪长斑岩锆石LA-ICP-MSU-Pb定年及Lu-Hf同位素研究

发布时间：2018-05-16 19:13

本文选题：西藏 + 朱诺斑岩铜矿　；参考：《矿物学报》2016年01期

【摘要】：朱诺斑岩铜矿床位于冈底斯成矿带的中段西部,是近年来新发现的大型斑岩铜矿床,矿体受控于新生代复式多期岩浆活动,成矿年龄为13.72 Ma,前人主要针对中新世岩浆活动开展研究,而对矿区另一类含矿石英闪长斑岩却鲜有报道,钻孔编录以及镜下鉴定表明石英闪长斑岩可能提供了部分成矿物质,因此详细开展含矿石英闪长斑岩的研究有利于拓展矿区的找矿方向。通过开展石英闪长斑岩原位锆石LA-ICP-MS U-Pb定年和Lu-Hf同位素测试。结果表明测试样品的加权平均年龄为51.47±0.6 Ma,代表该岩体的岩浆结晶年龄为始新世。锆石εHf(t)值介于-5.4~0.8,平均值为-2.4,176Hf/177Hf比值为0.28259~0.28276,平均值为0.28268,二阶段Hf模式年龄(TDM2)介于1.1~1.4 Ga之间,平均值为1.3 Ga。Lu-Hf同位素结果反映朱诺地区始新世岩体具有明显的古老地壳印记,岩浆源区为中-古元古代地壳物质并混染有少量的年轻基性物质,指示在拉萨地体南部,谢通门以西的朱诺地区存在中-古元古代结晶基地。
[Abstract]:The Juno porphyry copper deposit, located in the west of the middle section of the Gangdis metallogenic belt, is a large porphyry copper deposit newly discovered in recent years. The orebody is controlled by the Cenozoic complex magmatic activity. The ore-forming age is 13.72 Ma.The previous studies mainly focused on the Miocene magmatic activity, but there are few reports on another type of ore-bearing diorite in the mining area. The drill-hole cataloguing and microscopic identification indicate that the quartz diorite may provide part of the ore-forming material. Therefore, the detailed study of ore-bearing diorite is beneficial to the development of ore prospecting direction. The in situ zircon LA-ICP-MS U-Pb dating and Lu-Hf isotopic measurements of quartz diorite porphyry were carried out. The results show that the weighted mean age of the tested sample is 51.47 卤0.6 Ma.The magmatic crystallization age of the body is Eocene. The zircon 蔚 HF t) is between -5.4 ~ 0.8, the average value is -2.4176Hf- / 177Hf, the average is -2.28259Hf-0.28276and the average is 0.28268.The age of the two-stage HF model TDM2) is between 1.1 ~ 1.4Ga. The average value is 1.3 Ga.Lu-Hf isotope, which indicates that the Eocene rocks in Juno area have obvious ancient crustal imprint. The source area of the magma is the Meso-Paleoproterozoic crustal material mixed with a small amount of young basic material indicating that there is a Meso-Paleoproterozoic crystallization base in Juno area west of Xetomen in the southern part of Lhasa terrane.
【作者单位】：中国地质调查局成都地质调查中心;
【基金】：西藏米拉山铜矿整装勘查区专项填图与技术应用示范(编号:12120114050501) 西藏扎西康铅锌多金属矿整装勘查区专项填图与技术应用示范(编号:1212011221073)
【分类号】：P618.41;P597

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