浙闽赣中生代陆相火岩原始岩浆来源及其演化问题

根据同位素地球化学结合稀土元素配分模式特征,本区中生代火山岩原始岩浆来源于地壳和地幔二元组分相混合的体系。Sr同位素组成的计算,大致定量地显示由老而新由西向东加入的壳源组分逐渐减少,幔源组分逐渐增加。火山活动在时空和原始组分上,都呈现一致的演化规律。

THE SOURCE AND EVOLUTION OF PARENT MAGMA OF MESOZOIC VOLCANICS IN ZHEJIANG, FUJIAN AND JIANGXl

For a long time, geologists were interested in the magma source and evolution of Mesozoic volcanics in southeast China.In this paper,we discuss this problems on the basis of isotopic geochemistry and consider that the magmas are neither direct derivatives of the upper mantle nor the anatexis products of the lower crust,but are predominantly resultant from partial crust with contamination of upper mantle according to the data of (87)Sr/(88)Sr isotopic component of Sr, pb, O and the model of REE distrubution. The, calculation of Sr isotope component shows that the crust materials decrease continuously and mantle materials increase continuously from west to east with volcanism being younger. Therefor, the Mesozoic volcanism in this area shows the same trends in time, space and materials.