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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.
The addition of 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 Zircons are selected from the Yangfang aegiriteaugite syenites for Sensitive High-Resolution Ion Microprobe (SHRIMP -II) U-Pb geochronology study. 15 analyzes give concordant 206Pb / 238U ages in a narrow range of 233-249 Ma, which corresponds 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 pinch ndosinian orogeny in South China.