摘要
Abstract
Taking the volcanic rocks in the Wenwu Basin of Fujian Province as the research object,this paper conducts zircon U-Pb geochronology and rock geochemistry research.The results show that the rocks are enriched in Rb,Ba,K,moderately enriched in Th,U,Zr,Hf,and depleted in Nb,Ta,Ti and other elements,and the Sr anomaly is not significant,Zr/Hf value is 38.0～39.8,Nb/Ta value is 10.4～11.0,and Sr/Y value is 39.7～50.8,it exhibits the trace element characteristics of typical island arc volcanic rocks.Zircon U-Pb dating indicates that the weighted average ages of 206Pb/238U for the Late Cretaceous Zhaixia Formation rhyolite crystalline tuff and plagioclase rhyolite in the Wenwu Basin are 101.8 Ma±1.6 Ma and 99.9 Ma±1.1 Ma,respectively.Based on regional research results,the Late Cretaceous magmatic activity was characterized by the widespread development of bimodal volcanic rocks,indicating that the subducting plate began to retreat eastward,resulting in a backarc tectonic environment at that time.关键词
火山岩/锆石U-Pb年龄/地球化学/构造环境/温屋盆地/福建省Key words
volcanic rock/zircon U-Pb age/geochemistry/tectonic environment/Wenwu Basin/Fujian Province分类
天文与地球科学
