福建省中新生代古火山构造基本特征

福建位于我国东海之滨,环太平洋西部古火山带内,中新生代火山岩极为发育,尤以晚侏罗—早白垩世最为强烈,它们不仅规模庞大,且表现为由弱到强到弱的多次喷发。在闽东呈大面积分布,闽西则以单个盆地形式出现,面积约四万平方公里,占全省总面积的三分之一。新中国成立后,我们对中新生代火山岩进行了较系统的工作,特别是经过1∶20万区域

BASIC CHARACTERISTICS OF MESO-CENOZOIC PALEOVOLCANIC STRUCTURES IN FUJIAN PROVINCE

Fujian province lies within the circum-Pacific paleovolcanic belt,in the middle section of the Zhejiang-Fujian-Guangdong volcanic mobile belt. There,Mesozoic volcanic rocks,particularly those of Late Jurassic to Early Cretaceous ages,are very well developed. In Late Jurassic to Early Cretaceous times the volcanic activity reached a climax,so the extrusives of these ages cover one-third of the area of the whole province. Rocks are dominated by intermediate-acid volcanic rocks,which possess the characteristics of the continental margin calc-alkaline rock series There are mainly two types of volcanic eruption,the fissure type and the central type.The volcanic rock facies formed may be classified into explosive facies,effusive facies,viscous lava extrusion facies,volcanic vent facies,subvolcanic facies,volcanic-intrusive facies and eruptive-sedimentary facies.The volcanic structures are divided into six orders. Order Ⅰ is the circum-Pacific volcanic belt,order Ⅱ is the Zhejiang-Fujian-Guangdong volcanic mobile belt,order Ⅲ includes zones of volcanic eruption and volcanic basement uplift zones,order Ⅳ comprises areas（basins） of volcanic eruption and volcanic ring associations,order Ⅴ includes calderas,domes,linear volcanoes,cone—in-cone volcanoes,composite volcanoes and cupolas,and order Ⅵ includes central-type and fissure-type volcanic vents and cryptoexplosive breccia structure. The paper also preliminarily discusses the relations between volcanic structures and regional structures.