摘要
以五莲分岭山火山机构为例 ,运用高精度的4 0 Ar- 39Ar定年技术 ,对胶莱盆地青山组火山岩的形成年龄进行了精确测定。结果表明 ,青山组第一旋回中偏碱性富钾火山岩的形成年龄为10 9.9± 0 .6Ma ,第二旋回酸性流纹质火山岩形成年龄为 10 8.2± 0 .6Ma ,据此确定胶莱盆地青山组火山岩应为早白垩世岩浆活动的产物。根据该组火山岩在空间上具有自西向东年龄渐新的演变趋势 。
Based on a case study of the Fenlingshan volcanic apparatus, the formation ages of volcanic rocks of the Qingshan Formation in the Jiaolai Basin have been determined accurately by employing the highly precise 40 Ar- 39 Ar dating technique. Investigation results demonstrate that the age of intermediate to alkaline potash rich volcanic rocks of the first cycle of the Qingshan Formation is 109.9±0.6 Ma; and the age of the acidic rhyolitic volcanic rocks of the second cycle of the Qingshan Formation is 108.2±0.6Ma. It is thus evidenced that volcanic rocks of the Qingshan Formation in the Jiaolai volcanic Basin are products of Early Cretaceous magmatism. The ages of volcanic rocks of the Qingshan Formation in Shandong province display a progressively younger tendency eastwards, suggesting that the Mesozoic subduction of the Izanagi plate towards the Eurasian plate is the main dynamic factor that controlled the volcanism in this region.
出处
《高校地质学报》
CAS
CSCD
2001年第3期351-355,共5页
Geological Journal of China Universities
基金
国家自然科学基金项目 (编号 :49872 0 2 8)资助