| 廖辉宝,黄博韬,余泉,曾凡淼,李倩,陈振华,刘燚菲,张德富.青山—兆吉口地区花岗斑岩锆石 U-Pb年代学及地质意义[J].矿产勘查,2025,16(10):2223-2236 |
| 青山—兆吉口地区花岗斑岩锆石 U-Pb年代学及地质意义 |
| Zircon U-Pb chronology and geological significance of granite porphyry in the Qingshan-Zhaojikou |
| 投稿时间：2025-08-04 |
| DOI：10.20008/j.kckc.202510001 |
| 中文关键词: 花岗斑岩 锆石 U-Pb 地球化学 青山—兆吉口 |
| 英文关键词: granitic porphyry zircon U-Pb geochemistry Qingshan-Zhaojikou |
| 基金项目:本文受中国地质调查局地质调查工作子项目“江西1∶5万彭泽、郭家桥、太平关、五里街幅矿产地质调查(HYZB-013-2016)”和江西理工大学高层次人才科研启动项目(jxust-25)联合资助。 |
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| 中文摘要: |
| 青山—兆吉口地区赋铅锌矿花岗斑岩分布广泛，但对其形成时代、岩石类型及构造环境认识不足。本文开展锆石 U-Pb年代学、岩石地球化学及成因研究。LA-ICP-MS锆石 U-Pb年龄显示岩体形成于(148.3±2.5)Ma和(152.3±5.7)Ma，为晚侏罗世岩浆活动的产物，并捕获新元古代锆石。岩体 SiO2含量为 72.53%~74.7%，Al2O3含量为 13.82%~15.46%，全碱(Na2O+K2O)含量为 5.83%~6.37%，K2O/Na2O比值为 0.64~0.93， A/CNK值为 1.17~1.81。轻稀土相对富集，重稀土相对亏损，LREE/HREE=11.75~16.32，(La/Yb)N=13.47~26.67，Eu异常不明显，δEu=0.76~1.03，富集 Rb、Th、La、Hf等元素，亏损 Nb、Ta、P、Ti等元素。全岩锆饱和温度平均值为 804 ℃。地球化学特征显示岩体为强过铝质钙碱性 S型花岗岩。青山—兆吉口地区花岗斑岩是岩石圈幔源熔融岩浆及其底侵下地壳源岩浆混合的产物，形成于陆内造山环境。 |
| 英文摘要: |
| The granitic porphyry associated with lead-zinc deposits in the Qingshan-Zhaoji Kou area is exten.sively distributed; however, there remains a limited understanding of its age, rock type, and tectonic environment.This study conducts zircon U-Pb chronology alongside petrochemical and genetic analyses. LA-ICP-MS zircon U-Pb dating reveals that the rock mass was formed at (148.3±2.5) Ma and (152.3±5.7) Ma, indicating it is a product oflate Jurassic magmatic activity while also capturing Neoproterozoic zircons. The SiO2 content of the rock mass ranges from 72.53% to 74.7%, with Al2O3 content between 13.82% and 15.46%. The total alkali content (Na2O+ K2O) varies from 5.83% to 6.37%, while the K2O/Na2O ratio falls within the range of 0.64 to 0.93, and the A/CNKvalue spans from 1.17 to 1.81. The light rare earth elements (LREE) are relatively enriched, whereas the heavy rareearth elements (HREE) are comparatively depleted. The LREE/HREE ratio varies from 11.75 to 16.32, and the (La/Yb)N ratio ranges between 13.47 and 26.67. The Eu anomaly is not pronounced, with δEu values ranging from 0.76to 1.03. This rock exhibits enrichment in elements such as, Th, La, and Hf, while it shows depletion in Nb, Ta, P,and Ti. The average zircon saturation temperature for the whole rock is measured at 804℃. These geochemical char.acteristics suggest that the rock mass represents a strongly peraluminous calc-alkaline S-type granite. The graniticporphyry found in the Qingshan-Zhaojikou area is a product of the interaction between asthenospheric mantle-derived magmas and those originating from the lower crust. This formation occurred within an intracontinental oro.genic setting. |
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