摘要
根据中国东部100多个中生代花岗岩以及108个矿床的Pb,Sr,O和Nd同位素资料,把中国东部地壳基底岩石和中生代花岗岩划分为3个系列,在此基础上再划分出10个构造同位素地球化学省,并根据Pb同位素比值等值线勾画出不同“省”的边界和范围。对中国东部10个“省”中某些“省”的新生代玄武岩和中生代Pb同位素组成关系作了讨论,指出上地幔物质不均匀性不仅表现在水平方向,而且也表现在垂直方向上。考虑中生代花岗岩及新生代上地幔物质Pb同位素同步变化以及其它区域地球化学资料等特点,认为原始地幔物质的不均匀性比壳幔混合和/或分异引起的不均匀性的观点更易接受。
In this paper, based on the Pb, Sr, O and Nd isotope data of themore 100 Mesozoic granitoids and about 108 ore deposits in eastern China,authors suggest to classify the crustal basement rocks and Mesozoicgranitoids in eastern China into three discrete series. The three crustalbasement rock series may be at least further subdivided into tentectonic isotopic provinces, and the isograms of Pb isotope ratios on whichthe boundaries and forms of different tectonic isotope provinces weresketched out were plotted in eastern China on basis of the data. The relations between Cenozoic basanitoids and Mesozoic granotoids insome of the ten tectonic provinces are discussed. It is indicated that theupper mantle material is inhomogenous both in horizontal and in verticaldirections. During considering the synchronous change of Pb isotope forthe granitoids and the upper mantle as well as their regional geochemicalfeatures it is better for us to think that the original mantle was inhomogenousthan to think that this heterogeneity was caused by mixing and/ordifferentiations of mantle and crust.
基金
国家自然科学基金(48970166)
关键词
同位素
地质学
中生代
花岗岩
isotope geology
isotopice volution
geochemical province
Mesozoic era
eastern China
