摘要
总结了近十余年来福建省早中生代,尤其是早侏罗世火山作用研究的最新进展:早侏罗世火山地层在全省都有发现,采用化石和同位素测年对火山地层时代进行了精细确定,认为其主要形成于早侏罗世晚期。通过火山岩石地球化学特征的深入研究,永定地区的拉斑质玄武岩浆主要源于岩石圈地幔,但与来自富集岩石圈地幔的早白垩世玄武岩对比又具有明显的地球化学差异,不排除有来自软流圈地幔岩浆的加入。早侏罗世火山岩主要形成于板内的拉张环境,由于后造山应力松弛,沿北北东或北东向构造伸展致使地幔上隆(涌)-底侵的动力学机制是形成双峰式火山岩的内在因素。从早侏罗世火山作用入手来研究华南地区两大构造域的转换也取得了新的进展。论述了我省早侏罗世火山作用的研究方向,认为早中生代构造体制的转换与多金属成矿关系密切。
The paper presents the up-to-date researches of Early Mesozoic （especially Late Jurassic） volcanism in Fujian Province for past ten years. The Late Jurassic volcanic sequences can be found within Fujian Province and take shapes in late stage of Early Jurassic according to the information of organic remains and isotopic dating on the regional geological survey of the Yongding-Longyan areas. The in-depth study of characteristics of volcanic rock geochemistry shows that the tholeiite magma in the Yongding area should mainly be derived from the mantle of lithosphere and is provided with obvious differences of geochemistry contrasted with Early Cretaceous basalt which comes from the mantle of lithosphere, so that it is possible for the tholeiite magma to have pyrolite magma from the aesthenosphere interfused. The Early Jurassic volcanic rock in the surveyed area mainly forms from the within-plate extensional environment. The relaxation of stress in the post-orogeny stage, the upwarping and bottomintrusion of the mantle by the extension of NNE or north trend tectonics are the intrinsic factors of taking shape bimoda｜ volcanic rocks. It has made a new progress in studying the two tectonic domains in South China by starting with Early Jurassic volcanism. Finally, the paper has a discussion on the direction of the Early jurassic volcanism research. It is considered that the polymetal ore-forming process in the surveyed area has a close relation with the transition of Early Mesozoic tectonic framework.
出处
《福建地质》
2006年第4期169-179,共11页
Geology of Fujian
关键词
火山作用
玄武岩
构造转换
早中生代
福建
volcanism, basalt, tectonic transition, Early Mesozoic, Fujian Province
作者简介
陈润生（1968-）．男，高级工程师，地质矿产专业。
