福建早侏罗世火山地层对比及岩相古地理特征

通过对福建境内各地早侏罗世火山岩石组合及岩相组合特征的分析对比,认为闽西南永定地区为玄武岩（安山岩）-流纹岩组合,属强基性-弱酸性端元,东北部闽清上莲-永泰莲峰为安山质-流纹质组合,中部平和金京洋-西坑、长泰内寮-同安白交祠等地属安山岩-英安岩的单峰式组合,由西南往东北基性单元从玄武岩向玄武安山岩、安山岩过渡;火山岩形成的时间主要在170～188 Ma,形成时代为早侏罗世晚期-中侏罗世早期.通过早侏罗世火山-沉积盆地岩相古地理研究,发现其变化具有明显的规律,总的面貌是早侏罗世早期在闽西南地区遭受海侵,全省形成南海北陆的古地理格局,到早侏罗世晚期海侵结束,海水退出,福建全境上升为陆;火山活动沿沉积盆地呈北（北）东向带状分布,空间上可分为武平、尤溪-永定、闽清-平和等3个火山岩带,由南往北,由海相逐渐过渡为陆相,火山作用强度也愈来愈弱.

The correlation of early Jurassic volcanic stratigraphy and lithofacies-paleogeography characteristics,Fujian Province

Based on correlation and analysis of early Jurassic volcanic rocks assemblages and faces assemblages characteristics in every part of Fujian, this paper presents that Yongding area in south-western part of Fujian is regarded as basalts （andesites） rhyolite assemblage, belonging to strong basic-weak acidic end liner member, the northeastern part like Shanlian in Minqing, Lianfeng in Yongtai as andesitic-rhyolitic assemblage, whereas the middle part like Jingjinyang-Xikeng in Pinhe, Neiliao in Changtai, Baijiaochi in Tongan belong to andesitedacite unimodal assemblage. The basic units from SW towards NE transit from basalts to basaltic andesites and andesites. The formation time of volcanic rocks is between 170 Ma and 188 Ma, and the epoch is the late of early Jurassic and the early of middle Jurassic. On the basis of study on paleogeography of the volcanic-sedimentary basin faces during the early Ju- rassic, it is discovered that its change has an obvious rule. The general aspect is that.- the southwestern part of Fujian during the early Jurassic has suffered marine erosion, which resulted in the paleogeographic distribution that is the south is covered by water, while the north is covered by land. When the marine transgression ended in the late of early Jurassic, the sea water ebbed, the whole area of Fuiian raised to became land. The volcanic activities appear NNE belting along the sedimentary basin, which can be divided into three volcanic rocks belts as Wuping, Youxi-Yongding and Minqing-Pinghe in the view of space. From south to north, the marine faces transit gradually to land faces, and the volcanicity became weaker and weaker.