SHRIMP U-Pb zircon geochronology of Yangfang aegiriteaugite syenite in Wuyi Mountains of South China and its tectonic implications  

作　　者：WANGQiang ZHAOZhenhua JIANPing BAOZhiwei XlONGXiaolin MAJinlong 

机构地区：[1]GuangzhouInstituteofGeochemistry,ChineseAcademyofSciences,Guanlzhou510640,China [2]GeologicalInstitutelChineseAcademyofGeologicalSciences,Beijing100037.China

出　　处：《Chinese Science Bulletin》2003年第20期2241-2247,共7页

基　　金：supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX2-102);the National Natural Science Foundation of China(Grant Nos.40172028 and 40273019);the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX2-SW-117);the National Climbing Program of China(Grant No.95-Y-25);the Major State Basic Research Program of the People's Republic of China(Grant Nos.G1999043202 and 2001CB409803)

摘　　要：In addition to the wide spread peraluminous granites, some alkaline or alkali-rich intrusive rocks were recently observed in the Wuyi Mountains. The Yangfang aegiriteaugite syenites in the Wuyi Mountains are strongly enriched in light rare earth elements (LREE), K, Ba, Ga, Zr and Y. What is more, differentiations of REE are obvious. In addition, the Yangfang aegiriteaugite syenites have also some characteristics similar to A-type granite. Zircons are selected from the Yangfang aegiriteaugite syenites for Sensitive High-Resolution Ion Microprobe (SHRIMP-Ⅱ) U-Pb geochronology study. 15 analyses give concordant 206Pb/238U ages in a narrow range of 233—249 Ma, which correspond to a single age population with a weighted mean 206Pb/238U age of 242 4 Ma, which records the crystallization time of the aegiriteaugite syenites. It is suggested that: (1) there were early Triassic peralkaline intrusive rocks in South China; (2) the early Indosinian extension event was probably active in local area, South China. This discovery provides a new insight for farther understanding of 揑ndosinian orogeny in South China.In addition to the wide spread peraluminous granites, some alkaline or alkali-rich intrusive rocks were recently observed in the Wuyi Mountains. The Yangfang aegiriteaugite syenites in the Wuyi Mountains are strongly enriched in light rare earth elements (LREE), K, Ba, Ga, Zr and Y. What is more, differentiations of REE are obvious. In addition, the Yangfang aegiriteaugite syenites have also some characteristics similar to A-type granite. Zircons are selected from the Yangfang aegiriteaugite syenites for Sensitive High-Resolution Ion Microprobe (SHRIMP-Ⅱ) U-Pb geochronology study. 15 analyses give concordant 206Pb/238U ages in a narrow range of 233—249 Ma, which correspond to a single age population with a weighted mean 206Pb/238U age of 242 4 Ma, which records the crystallization time of the aegiriteaugite syenites. It is suggested that: (1) there were early Triassic peralkaline intrusive rocks in South China; (2) the early Indosinian extension event was probably active in local area, South China. This discovery provides a new insight for farther understanding of 揑ndosinian orogeny in South China.

关 键 词：中国南部 武夷山 霓辉石 正长岩 锆石U-PB测年 地球年代学 地质构造 

分 类 号：P588.122[天文地球—岩石学] P597.3[天文地球—地质学]