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内蒙古敖仑花钼矿床位于大兴安岭成矿带中南段,是西拉木伦河北岸一个典型的斑岩型钼矿床.为了精确厘定该矿床含矿岩体的成岩时代,进行了锆石LA-ICP-MS U-Pb年代学研究,结合花岗岩中锆石的微量元素特征对该矿床成矿岩体物质来源进行了深入的探讨.花岗斑岩锆石LA-ICP-MS年代学研究表明花岗斑岩的结晶年龄为135.0±1.0Ma,为燕山期大规模中酸性岩浆活动的产物.该岩体锆石Th/U比值大于0.1,具明显的Ce正异常(Ce*为1.72～188.71)和Eu负异常(Eu*为0.05～0.57),轻稀土亏损,重稀土富集,La和Pr含量很低,而Ce正异常,显示为壳源岩浆锆石的特征.纵观矿床地质特征、成岩时代和区域构造演化,认为敖仑花钼矿床形成于大兴安岭成矿带140Ma左右的锡多金属成矿高峰期,矿床形成于由挤压造山向碰撞伸展过渡阶段的构造背景.通过与西拉木伦河北岸新发现的钼矿床对比分析,认为天山-林西为重要的钼成矿带,这对提高该类矿床的理论研究水平和指导隐伏金属矿床的找矿勘查工作均具有重要意义.
The Aolunhua molybdenum deposit in Inner Mongolia is located in the middle and southern part of the Daxinganling metallogenic belt and is a typical porphyry molybdenum deposit on the northern bank of the Xilamulun River.In order to accurately determine the diagenetic age of the ore-bearing rock mass in this deposit, zircon LA- ICP-MS U-Pb geochronology, and combined with the trace element characteristics of zircons in granite, the source of ore-forming rock mass in this deposit has been discussed in depth. The zircon LA-ICP-MS chronological study of the granite porphyry shows that the flower The crystallization age of the porphyry is 135.0 ± 1.0Ma, which is the product of the large-scale intermediate-acid magmatic activity in the Yanshanian period.The Th / U ratio of the zircon is greater than 0.1 and the Ce positive anomaly (Ce * = 1.72-188.71) And Eu negative anomalies (Eu * of 0.05-0.57), depleted in light rare earths, enriched in heavy rare earths, with low La and Pr contents and positive Ce anomalies, showing the characteristics of crust-derived magmatic zircon. Looking at the geological features of the deposits, Diagenetic era and regional tectonic evolution, it is considered that the Aolunhua molybdenum deposit was formed at the peak of tin polymetallic mineralization about 140Ma in the Da Hinggan Mountains metallogenic belt, and the deposit formed in the tectonic setting of the transitional stage from crustal to crustal extension.By combining with Silas Comparative analysis of newly discovered molybdenum deposits on the north bank of the Mulun River suggests Tianshan-Lin Molybdenum is an important metallogenic belt, which are of great significance to improve the level of theory and mineral exploration guidance concealed metal deposits of such deposits.