腾冲、长白山、五大连池新生代火山岩Sr、Nd、Pb同位素地球化学特征

GEOCHEMICAL FEATURES OF Sr,Nd,AND Pb ISOTOPES OF VOLCANIC ROCKS IN CENOZOIC ERA IN TENGCHONG, CHANGBAISHAN AND WUDALIANCHI,CHINA

概括了腾冲、长白山、五大连池新生代火山岩岩石学、岩石化学基本特征，探讨了Ｓｒ、Ｎｄ、Ｐｂ同位素地球化学特征和岩浆源区性质。腾冲火山岩为高钾钙碱性岩系，高８７Ｓｒ／８６Ｓｒ、高２０６Ｐｂ／２０４Ｐｂ、２０８Ｐｂ／２０４Ｐｂ、低１４３Ｎｄ／１４４Ｎｄ，岩浆源区为俯冲带再循环富集地幔。长白山火山岩为超钾钙碱性岩系，低Ｓｒ高８７Ｓｒ／８６Ｓｒ，εＮｄ为－２３—＋２９，Ｐｂ同位素组成变化不大，岩浆源区为俯冲带再循环地幔。五大连池火山岩为超钾碱性岩系，高８７Ｓｒ／８６Ｓｒ、低１４３Ｎｄ／１４４Ｎｄ和２０６Ｐｂ／２０４Ｐｂ、２０８Ｐｂ／２０４Ｐｂ，岩浆源区为地幔内部交代作用所产生的富集地幔。

In this paper, the basic features of petrology and petrochemistry of cenozoic volcanic rocks in Tengchong, Changbaishan and Wudalianchi have been summarized, and the characteristics of Sr, Nd, Pb isotopic geochemistry and the nature of magma origin region have been studied. Volcanic rocks in Tengchong are the high K calc alkaline series of rocks with high 87 Sr/ 86 Sr, 206 Pb/ 204 Pb and 208 Pb/ 204 Pb and low 143 Nd/ 144 Nd, and their magmas originate from the recycle enriched mantle of subduction zone. Volcanic rocks in Changbaishan are the ultrapotassic calc alkaline series of rocks with low Sr, high 87 Sr/ 86 Sr, Nd of 2 3—+2 9 and variable Pb isotopic composition, and their magmas originate from the recycle mantle of subduction zone. Volcanic rocks in Wudalianchi are the ultrapotassic alkaline series of rocks with high 87 Sr/ 86 Sr and low 143 Nd/ 144 Nd, 206 Pb / 204 Pb and 208 Pb/ 204 Pb,and their magmas originate from the enriched mantle resulting from the metasomatism in mantle.