南海北部—台湾海峡及邻区新生代火山活动时序与分布

EPISODES AND DISTRIBUTION OF CENOZOIC VOLCANISM IN NORTHERN PART OF SOUTH CHINA SEA AND TAIWAN STRAIT AS WELL AS THEIR NEIG HBORING AREAS

南海北部—台湾海峡新生代火山喷发始于古新世,结束于第四纪,可分为8个活动期。古新世—早中新世火山活动限于断陷盆地系内;中新世中、晚期喷发范围增大,扩展到闽浙沿海陆区;上新世以来逐渐向西缩小至南海。早第三纪形成玄武质—长英质双模式火山岩系列,晚第三纪—第四纪主要形成碱性玄武岩和拉斑玄武岩系列,研究区新生代火山作用的发展演化与本区所处的特殊的大地构造背景和动力学环境有关,反映了东亚大陆壳体和菲律宾海壳体的相互作用和动力场变化,具有东亚陆缘型裂谷火山活动的特点。

The Cenozoic Volcanism in the northern part of the South China Sea (SCS) and the Taiwan Strait, which could be divided into eight episodes, began in the paleocene and ended in the Quarternary. The volcanic activities in the period from the Paleocene to the Early Miocene were limited in the graban basins at that time. The eruptive extent in the middle and late Miocene of Miocene epoch expanded and spread to the continental areas along the coast of Fujian and Zhejiang provinces. Since the Pliocene the volcanism gradually reduced its scope to the west and concentrated in SCS. Biomodal basaltic and felsic volcanic series were formed in the Early Tertiary. Alkali—basa. It and tholeiite series were mainly formed from the iate tertiary to the Quztermary. The development and evolution of the Cenozoic volcanism in the region studied had relations to the special geotectonic setting and geodynamic environment, reflecting the mutual action between the East Asia continental crustobody and the Philippine sea crustobody and the changes of the geodynamic field, being of characteristics of the East Asia epicontinental type rift volcanism.