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滇西古特提斯构造带某些玄武岩的Ｓｒ、Ｎｄ、Ｐｂ同位素资料显示存在富集放射成因Ｐｂ同位素的Ｄｕｐａｌ异常。五素玄武岩的：８７Ｓｒ／８６Ｓｒ＝０．７０６３，εＮｄ（Ｔ）＝５．４─６．５；铜厂街洋岛玄武岩的８７Ｓｒ／８６Ｓｒ＝０．７０３６─０．７０８３，εＮｄ（Ｔ）＝０．６５─６；双沟、德钦、铜厂街、勐连蛇绿岩玄武岩的８７Ｓｒ／８６Ｓｒ＝０．７０３８─０．７０７３，εＮｄ（Ｔ）＝８．２─１０．９．Ｓｒ、Ｎｄ同位素资料表明这些玄武岩来源于地幔源区，未受壳源物质的混杂，而个别８７Ｓｒ／８６Ｓｒ异常高值与其形成之后的海水蚀变作用有关，并不影响其Ｎｄ、Ｐｂ同位素组成。Ｐｂ同位素组成表明它们具有异常高的放射成因Ｐｂ，显示其地幔源区具Ｄｕｐａｌ异常特征，而Ｄｕｐａｌ异常源区的形成与古代洋壳俯冲带入深部地幔的壳源物质参加到地幔重新循环有关。
The Sr, Nd and Pb isotope data of some basalts in the ancient Tethys tectonic belt of western Yunnan show that there is a Dupal anomaly enriched in radiogenic Pb isotopes. Five-element basalts: 87Sr / 86Sr = 0.7063, εNd (T) = 5.4─6.5; 87Sr / 86Sr = 0.7036─0.7083, εNd (T) = 0.65 ~ 6; 87Sr / 86Sr = 0.7038─0.7073, εNd (T) = 8.2─10.9 in Shuanggou, Deqin, Tongchang Street and Menglian ophiolite basalts. Sr and Nd isotopic data indicate that these basalts originated from the mantle source and are not interbedded with crustaceous materials. However, the abnormally high values of 87Sr / 86Sr correlate with seawater alteration after their formation, and do not affect their Nd and Pb isotopic compositions. The Pb isotopic composition indicates that they have abnormally high radiogenic Pb, which indicates that the mantle source area is characterized by Dupal anomaly. The formation of Dupal anomalous source area is related to the recirculation of the mantle by the crust-source material of the ancient mantle subducted into the deep mantle.