摘要
华南沿海晚新生代玄武岩喷发时代以上新世至晚更新世为主,其特征为多期次喷发且晚期火山碎屑物增多、火山活动有随时间而迁移的趋势、喷发型式由裂隙式向中心式发展。玄武岩以拉斑玄武岩系列为主,兼有碱性玄武岩系列及过渡系列,后二者含地幔岩包体及巨晶。玄武岩的物质来源于地幔岩的局部熔融;经历了分离结晶作用及同化混染作用。玄武岩岩石化学图解表明雷琼地区第三纪属陆内裂谷构造环境,第四纪裂谷闭合,在断陷区内产生陆相玄武岩喷发。闽东南地区玄武岩浆则沿大陆边缘平行的张性断裂系中喷出。
The eruption of the late Cenozoic basalts along the coast of South China mainly took place during the period from Pliocene to late Pleistocene. It was characterised by multiple stage eruptions, with pyroclastie materials increasing from early to late. The volcanic activities had a tendency to migration in space with the passage of time and the eruption type tended to evolve from fissure eruption to central—vent one. The basalts are mainly tholeiitic with some alkali and transitional series, and the latter two series contain xencliths and huge crystals of pyrolite. The materials of basalts were derived from the local melting of pyrolite and had undergone fractional crystallization and assimilation contamination. Petrochemical plots of the basalts show that the region of Leizhou Peninsula and North Hainan belonged to a continental rift environmunt in the Tertiary, and with the closing of the rift in the Quaternary, there occurred terrestrial eruptions of basaltic magma in the graben area; whereas the eruptions in the southeastern area of Fujian province took place along the extensional fractures paralleied to the continental margin.
出处
《中山大学学报论丛》
1992年第1期93-103,共11页
Supplement to the Journal of Sun Yatsen University
基金
国家自然科学基金
关键词
玄武岩
火山活动
晚新生代
构造环境
华南沿海
basalt
volcanic activity
late Cenozoic
tectonic environment
coast of the South China Sea
