地质通报2024，Vol.43Issue(5)：839-858,20.DOI:10.12097/gbc.2022.07.047
腾冲地块晚白垩世小龙河花岗岩年龄及其成矿意义
Geochronology and mineralization significance of the Late Cretaceous Xiaolonghe granite in the Tengchong Block
摘要
Abstract
In order to determine the Late Cretaceous tectonomagmatic activities and the significance of granite mineralization in the Tengchong Block,this study applied the comprehensive methods of geochronology,Sr-Nd-Pb isotopic and whole-rock geochemical analyses to probe Xiaolonghe granites.The results show that the Xiaolonghe pluton is composed of fine-grained leuco-monzogranite and porphyritic-like biotite monzogranite.Zircon U-Pb chronological data indicate that their magmatic crystallization ages are 67.0±1.0 Ma and 68.5±1.6 Ma respectively,and the Re-Os model ages of molybdenite are 67.15±0.99 Ma and 69.02±1.22 Ma respectively,both of which are the products of the Late Cretaceous tectonomagmatic activities.The characteristics of Sr-Nd-Pb isotopes and major and trace elements show that the fine-grained leuco-monzogranite is S-type granite((87Sr/86Sr)i=0.757～0.763,εNd(t)=-8.89～-8.99),and the magma originated from the partial melting of clay-rich hard sandstone in the upper crust of Mesoproterozoic(TDM2=1.59～1.60 Ga),which is closely-related to the formation of Xiaolonghe tin-tungsten polymetallic deposit.The porphyritic-like biotite monzogranite is I-type granite((87Sr/86Sr)i=0.711,εNd(t)=-8.72～-9.16),and the magma originated from the remelting of clay-rich hard sandstone in the lower crust of Mesoproterozoic(TDM2=1.58～1.62 Ga).The Late Cretaceous Xiaolonghe granites and its tin-tungsten mineralization in the Tengchong Block are the products of magmatic activity and hydrothermal process caused by the collision or post-collision between the Tengchong Block and the Baoshan Block after the closure of the Meso-Tethys Bangong-Nujiang ocean.关键词
腾冲地块/晚白垩世/锆石SHRIMP U-Pb定年/辉钼矿Re-Os定年/锶-钕-铅同位素地球化学Key words
Tengchong Block/Late Cretaceous/zircon SHRIMP U-Pb geochronology/molybdenite Re-Os dating/Sr-Nd-Pb isotope geochemistry分类
天文与地球科学引用本文复制引用
刘金梁,陈永清,尚志..腾冲地块晚白垩世小龙河花岗岩年龄及其成矿意义[J].地质通报,2024,43(5):839-858,20.基金项目
云南省重点研发计划项目《云南省西部重点矿产成矿规律与分布预测研究》(编号:202303AA080006),国家自然科学基金项目《成矿系统自组织临界性与矿床定位预测》(批准号:41972312)、《深部致矿异常信息提取与高精度数字找矿模型建立》(批准号:41672329)、《超大型矿床成矿复杂性特征与成矿动力学机制探索》(批准号:41272365),国家重点研发计划课题《"三联式"数字找矿模型与深部定量成矿预测》(编号:2016YFC0600509) （编号:202303AA080006）
