福建省地壳——上地幔结构及深部构造背景的研究

Crust-Upper-Mantle Structure and Deep Structural Settng of Fujian Province

本文主要根据区域、深部物探资料成果,结合地质特征,综合论述了与福建省地壳—上地幔及深部构造背景有关的重要基础地质问题:本省地壳可分为上、中、下三层,内有七个速度层,壳—幔分为七个电性层,据此建立了地壳—上地幔综合柱状图及圈层结构综合模式;省内断裂分为岩石圈、地壳、基底、盖层四种类型,最重要的断裂有七条,总结出本省构造格架具有东西分带、南北分块的特征;深部构造从东到西地幔具有陡坡带—坳陷带—缓隆带及岩石圈顶面具有深凹陷—狭窄隆起带—隆起的分区特点;提出松溪—长汀、滨海两条古俯冲带,将本省及邻区划分为武夷、戴云、台湾三个古板块及四个相应大地构造单元;提出在同安—莆田—带深凹陷上存在印支期古俯冲事件残迹,并探索了与其有关的四个大型推覆构造、三个环状构造,以及东部火山岩区存在古裂堑构造等;将省内花岗岩类成因划分为 I、S 及过渡型,探讨了它与深部构造及与板块活动关系等;论述了深部构造与内生金属矿床分布的关系,总结出了控制本省矿床形成的七种基本要素,圈出了三条主要成矿远景带及17个远景区,为今后进一步开展地勘工作提供了依据。

The paper focuses on the discussion of important geological problems about the crust-upper-mantleand deep structural setting of Fujian Province.Some important information about the crust-upper-mantle structure and deep structural setting are acquired after analyzing the regional and deep geophysicalprospecting data and associated geological data.The crust in Fujian Province can be divided into the up- per,middle and lower layers in which there exist seven velocity layers and the crust-mantle is groupedinto seven electrical layers,in view of which the synthetic column of the crust-upper-mantle (litho-sphere) and the synthetic model of layer-sphere structure are established.There are the lithospheretype,crust-type,basement-type and cover-type faults in Fujian Province,among which there occurseven major faults.The tectonic framework of Fujian Province possesses the characteristics of zoningin the EW direction and blocking in the SN direction.The mantle in Fujian Province from east to westis divided into abrupt slope zone,down-wraped region and gently uplift and the top of lithosphere intodeep depression,narrow doming and uplift.It is inferred that Shongxi-Changting and Binhai palaeo-subduction belts divide Fujian Province and its neighbouring regions into three palaeoplates (Wuyi,Taiyun and Taiwan) and four related tectonic units.There are relics of Indosinian palaeosubductionevent in the Tongan-Putian area of southern Fujian.The genetic types of granites in Fujian Provinceare divided into the I-type,S-type and transitional type.After studying four large-scale related nappestructures and three ring-like structres,and palaeoaulacogen structure in volcanic terrain of eastern Fu-jian,the authors make a discussion on the relations of deep structures with plate motion and of deepstructures with endogenetic metallic ore-deposit.Finally,we present seven essentical factors of control-ling the ore-deposit formation in Fujian Province,and outline three major mineralization prospectivebelts and seventeen prospect areas,which provide the basis for the further geological exploration.