福建龙海明溪两区玄武质火山岩钾-氩年龄和Nd、Sr、Pb同位素  

Nd, Sr, Pb ISOTOPES AND K-Ar AGE OF BASALTIC ROCKS IN LONGHAI AND MINGXI, FUJIAN PROVINCE

作　　者：陈道公[1] 张剑波 

机构地区：[1]中国科技大学地球与空间科学系,合肥230026

出　　处：《岩石学报》1992年第4期326-331,共6页Acta Petrologica Sinica

基　　金：国家自然科学基金

摘　　要：本文给出了福建龙海明溪两区玄武质岩石的K-Ar年龄测定结果,其中龙海为16.57～19.20Ma,属第三纪中新世的产物;明溪则均小于5Ma,为上新世至更新世所喷发。通过Sr、Nd、Pb同位素组成分析,讨论了两区玄武岩的源区特征及其成因。The K-Ar age of basaltic rocks in Longhai and Mingxi, Fujian Province indicates that the Longhai basalt was erupted in Miocene and Mingxi basalt was erupted from Pliocene to Pleistocene. The characteristics and genesis of basaltic rocks in the two areas are discussed from the data of Sr, Nd, Pb isotopic compositions in this paper. ^(143)Nd/^(144)Nd ratio varies from 0.512745 to 0.513055, ^(87)Sr/^(86)Sr from 0.703644 to 0.704559, and Pb isotopic composition is 17.55～18.41, 15.36～15.58, and 37.61～38.65. The wide range in radiogenic Sr, Nd and Pb isotopic compositions show regional heterogeneity of the mantle. Defference and relation between these basaltic rocks in isotopic compositions reflect that the environment was a transition zone from ocean to continent, their source was mainly the depleted mantle, and a mixing reaction took place in the mantle source.

关 键 词：玄武岩 钾 氩 年龄 同位素 SR 

分 类 号：P588.145[天文地球—岩石学]