摘要
溧水火山岩盆地是长江中下游地区众多中生代火山岩盆地之一,在盆地内自下而上发育有龙王山组、大王山组、姚家边组和甲山组粗面质火山岩和若干个同源的次火山侵入岩体。针对溧水盆地火山岩-次火山岩进行系统的锆石U-Pb年代学研究,结果显示,龙王山组玄武质粗面岩的锆石U-Pb年龄为135 Ma±1 Ma,大王山组粗安岩的锆石U-Pb年龄为131 Ma±1 Ma,姚家边组粗安岩的锆石U-Pb年龄为128 Ma±1 Ma,另外1个粗安斑岩体的年龄为131 Ma±1 Ma,它们均为早白垩纪岩浆活动的产物。上述年龄数据与长江中下游地区其他盆地火山岩的年龄基本一致,表明长江中下游地区中生代火山岩的喷发时代主要集中在135Ma^127Ma之间,均受制于中国东部岩石圈减薄的伸展构造背景。
Lishui volcanic basin is one of the Mesozoic volcanic basins＇in the Yangtze River region. There are Longwangshan Formation, Dawangshan Formation, Yaojiabian Formation and Jiashan Formation developed from the bottom to the top with trachy.tic,rhyolitic volcanic rocks as the main lithology, combined with several homologous sub-volcanic intrusive rocks. Systematic zircon U-Pb age study was conducted to the volcanic-subvoleanic rocks in the Lishui Basin. The results showed that the zircon U-Pb ages of the trachytic basalt in the Longwangshan Formation, the latites （trachy andensite） in the Dawangshan Formation and the latites （traehy andensite） in the Yaojiabian Formation are 135 Ma±1 Ma,131 Ma±1 Ma and 128 Ma±1 Ma respectively,with another age of trachyandensitic porphyry of 131 Ma± 1 Ma. They are all the product of early Cretaceous magmatism. The above ages agree with the ages of other volcanic rocks in the basins of the Yangtze River region,suggesting that the eruption ages of the Mesozoic volcanic rocks in the Yangtze River region are mainly concentrated between 135 Ma- 127 Ma, and are subject to thinning extensional tectonic background in eastern China lithosphere.
出处
《矿物岩石》
CAS
CSCD
北大核心
2015年第2期25-31,共7页
Mineralogy and Petrology
基金
华东基础地质综合调查与片区总结(1212011220542)
