黄梅县婆婆寨岩体锆石U-Pb年代学及岩石地球化学特征研究  

Zircon U-Pb Geochronology and Geochemical Characteristics of Popozhai Rock Mass in Huangmei County

作　　者：钟石玉 徐浩 汤旋 胡太平 杨成 王小敏 阮业东 黄丽 Zhong Shiyu;Xu Hao;Tang Xuan;Hu Taiping;Yang Cheng;Wang Xiaomin;Ruan Yedong;Huang Li(Hubei Geological Survey,Wuhan,Hubei 430034;First Geological Brigade of Hubei Geological Bureau,Daye,Hubei 435100)

机构地区：[1]湖北省地质调查院,湖北武汉430034 [2]湖北省地质局第一地质大队,湖北大冶435100

出　　处：《资源环境与工程》2022年第4期453-462,共10页Resources Environment & Engineering

基　　金：湖北省综合性地质区划(全省综合)(KCDZ2022-01);湖北省战略性矿产资源安全保障及发展战略研究(KJ2022-53)。

摘　　要：黄梅县婆婆寨岩体属于南大别地体南缘广泛出露的花岗岩体之一,迄今研究较为薄弱。为查明该岩体成岩时代,探讨岩石成因及其形成的大地构造环境,利用激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)技术对婆婆寨岩体进行了锆石U-Pb年龄测定,并开展了系统的岩石学和岩石地球化学研究。婆婆寨岩体遭受了强烈的韧—脆性变形,主要岩性为碎裂岩化正长花岗岩。岩石中锆石为自形—半自形双锥长柱状,一般发育较完好清晰的振荡环带,显示岩浆成因锆石特征。婆婆寨岩体的锆石^(206)Pb/^(238)U年龄为(792.7±5.9)~(780.1±5.5)Ma,属于青白口纪侵入岩。婆婆寨岩体主微量与稀土元素地球化学特征表明,其属于弱过铝质钾玄岩系列岩石,富集Rb、Zr、Hf、U、Th,亏损Ba、Nb、Sr、P、Ti、Cr、Ni等元素;稀土元素总量较高,轻稀土富集而重稀土亏损,且轻稀土较重稀土分异明显,显示较强烈的铕负异常。婆婆寨岩体属于铝质A型花岗岩,是桐柏—大别微陆块和扬子板块碰撞造山运动结束之后初始拉张阶段的产物。Popozhai rock mass in Huangmei County is one of the granite bodies widely exposed in the southern margin of the South Dabie terrain,and the research is relatively weak so far.In order to identify the diagenetic age of the rock mass and explore the petrogenesis and tectonic environment of its formation,the laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS)technology is used to determine the zircon U-Pb age of the Popozhai rock mass,and a systematic study of petrology and petrochemistry is carried out.Popozhai rock mass suffered from strong ductile-brittle deformation,and the main lithology is cataclastic syenogranite.The zircons in rocks are self-shaped and semi-self-shaped biconical long columnar,and generally have well-developed clear oscillation ring,indicating the characteristics of magmatic zircons.The ziron ^(206)Pb/^(238)U age of Popozhai rock mass is(792.7±5.9)~(780.1±5.5)Ma,which belongs to Qingbaikou intrusive rock.The main trace and REE geochemical characteristics of the Popozhai rock mass show that it belongs to the weakly peraluminous potassium basalt series,which is enriched in Rb,Zr,Hf,U,Th,and depleted in Ba,Nb,Sr,P,Ti,Cr,Ni and other elements.The total amount of rare earth elements is high,light rare earth is enriched and heavy rare earth is depleted,and the difference between light rare earth and heavy rare earth is obvious,showing a strong negative Eu anomaly.Popozhai granite belongs to aluminum type A granite,which is the product of the initial tension stage after the end of the Tongbai-Dabie microcontinent and Yangtze plate collision orogenic movement.

关 键 词：婆婆寨岩体 U-PB年代学 岩石地球化学 岩石成因 大地构造环境 黄梅县 

分 类 号：P597[天文地球—地球化学]