摘要
本文根据长江中下游地区中生代侵入岩长石Pb同位素组成和Nd同位素模式年龄研究,提出长江中下游地区是由几个晚太古-早元古代和中元古代块体组成的变质基底;其地壳的形成具有多阶段演化的特点,大致是:晚太古代(>2500Ma)形成古陆核,早元古代(2500-1900Ma)陆壳初步形成,中元古代(1800-1200Ma)陆壳快速增长,晚元古代(1000Ma)以后区内陆壳增生基本趋于停止。
Based on Pb isotope compositions and Nd isotope model ages of feldspar for the Mesozoic intrusive rocks in the Middle-Lowet Reaches of Yangtze River, the authors suggest the metamorphic basement consist of several terrains of late Archean-early Proterozoc and middle Proterozoic. The formation of crust is characteristic of the poly-stage evolution. An evolutionary process is described. The old nuclus formed in late Archean (>2500Ma). The orisinal crust formed in early Proterozoic (2500- 1900Ma),growing rapidly in Middle Proterozoic (1800-200Ma) and ceased growing in late Proterozoic (<1000Ma).
出处
《火山地质与矿产》
1996年第3期42-50,共9页
Volcanology & Mineral Resources
基金
国家攀登项目!A30
关键词
长江中下游地区
变质基底
地壳
形成时间
Middle-Lower Reaches of Yangtze Rirer Metamorphic basement crust growing