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武夷山地区是华南过铝质花岗岩的重要分布区。近期的研究表明,该区存在碱性或富碱侵入岩。武夷山洋坊霓辉石正长岩的元素地球化学特征显示其为过碱性侵入岩,强烈富轻稀土和K,Ba,Ga,Zr,Y等元素,轻重稀土元素强烈分异,具有A型花岗岩的一些特征;锆石的SHPIMP U-Pb年龄研究显示,15个分析点给出~(206)Pb/~(238)U年龄为233～249 Ma,加权平均值为242±4 Ma,记录了霓辉石正长岩的结晶年龄。这表明:(1)华南存在早三叠世(242±4 Ma)的过碱性侵入岩;(2)在印支早期,华南局部可能存在伸展作用。武夷山早三叠世过碱性侵入岩的发现为进一步研究华南“印支运动”的特点提供了新的思路。
Wuyishan area is an important distribution area of South China peraluminous granite. Recent studies have shown that alkaline or alkali-rich intrusive rocks exist in this area. The elemental geochemical characteristics of the Yangfangshi quartzite in Wuyishan show that it is overbasic intrusive rock, strongly enriched in light rare earths and elements such as K, Ba, Ga, Zr and Y. The light and heavy rare earth elements are highly differentiated and have type A Some characteristics of granite; SHPIMP U-Pb ages of zircons show that ~ (206) Pb / ~ (238) U ages are 233 ~ 249 Ma and the weighted average is 242 ± 4 Ma at 15 analysis points, The crystal age of the Ni-Shih syenite. This indicates that: (1) Early Triassic (242 ± 4 Ma) over-alkaline intrusive rocks exist in southern China; (2) In the early Indosinian period, there may be stretching in some parts of southern China. The discovery of overbasic intrusive rocks in the Early Triassic of Wuyishan provides new ideas for further studying the characteristics of the “Indosinian Movement” in South China.