福建沿海长乐—诏安构造带（北段）研究

发布时间：2018-01-29 23:05

本文关键词： 长乐—诏安构造带构造片理锆石U-Pb测年中生代构造应力场　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：长乐—诏构造带位于福建沿海,历史上曾在构造带内部及周边发生过多次强烈地震。但是,对该构造带的认识仍众说纷纭。福建沿海是我国经济发展的前沿地带,是实施海洋战略的出发点。本文选取长乐—诏安构造带北段(即福州—莆田段)为研究对象,系统追索调查了北段的构造变形、测量了大量的片理化带产状,并进行了相关样品的采集。通过对野外资料的分析整理、样品的分析测试,并结合区域地质资料和前人研究成果,较为系统地研究了该构造带北段的构造变形特征、新构造活动特征、构造年代学、构造应力场及构造演化。长乐-诏安构造带北段的总体构造变形特点主要表现为宽达数十公里的强烈构造片理(劈理)化带;相关的岩石一般都表现出了不同程度的显微构造变形特征;表明主要为中等构造层次形成的变形构造与弱动力变质岩。沿构造片理化带发育大致同期的基性岩墙群;并在该区首次发现假玄武熔岩的共生现象。该构造带的新构造期断层较弱;地表未见规模大、活动强、位移显著的活动断裂带标志;其历史强震活动水平并不高;推测并不是一条活动的深大断裂带。构造带的年代学研究表明,主体构造变形(北东向构造片理化带)是与中生代中-晚期的岩浆活动和变质作用同期的,其形成过程可大致分为三个阶段:(1)中侏罗世-晚侏罗世早期、(2)晚侏罗世末-早白垩世早期、(3)早白垩世晚期,其中最主要的形成阶段为晚侏罗世末-早白垩世早期。本文在早白垩世基性岩墙群的锆石测年中发现了12个古元古代—中元古代的年龄值(1400~2500Ma)、5个新元古代的年龄值(800~1400Ma)及4个晚古生代的年龄值(250~400Ma);它们可能反映了深部基底不同时代的原岩信息;推测该带可能存在“华夏古陆”基底及加里东褶皱带与晚古生代沉积盖层。根据“构造片理化”带的统计分析可划分出两期古构造应力场,分别主要对应于北东向和北西向构造片理化带的发育时期;前者主压应力方向为南东-北西向,是中、晚侏罗世到早白垩世的主体构造形成期;后者主压应力方向为南西-北东向,主要作用于晚白垩世。
[Abstract]:The Changle-Zhao structural belt is located along the coast of Fujian. There have been many strong earthquakes in and around the tectonic belt in history. The understanding of the tectonic belt is still divided. Fujian coastal area is the frontier of economic development in China. In this paper, the north segment of the Changle-Zhaoan structural belt (Fuzhou-Putian section) is selected as the research object, the structural deformation of the northern segment is investigated systematically, and a large number of sheet physical-chemical belt occurrence is measured. Through the analysis of field data, sample analysis and test, combined with regional geological data and previous research results. The characteristics of tectonic deformation, neotectonic activity and tectonic chronology in the northern segment of the tectonic belt are systematically studied. Tectonic stress field and tectonic evolution. The general structural deformation characteristics of the northern segment of the Changle-Zhaoan tectonic belt are mainly characterized by a strong tectonic lithocline (cleavage) belt with a width of tens of kilometers. The related rocks generally show different microstructural deformation characteristics. It shows that the deformation structure and weakly dynamic metamorphic rock are mainly formed at the middle tectonic level. The symbiotic phenomenon of pseudo-#china_person0# lava was found for the first time in this area. There is no sign of active fault zone with large scale, strong activity and significant displacement on the surface of the earth. Its historical strong earthquake activity level is not high; The chronological study of the tectonic belt indicates that the main tectonic deformation (NE tectonic sheet physical and chemical belt) is in the same period with the late Mesozoic magmatic activity and metamorphism. The formation process can be roughly divided into three stages: 1) Middle Jurassic to early late Jurassic, 2) late Jurassic to early Cretaceous, 3) late early Cretaceous. The most important stage of formation was the late Jurassic to early Cretaceous. In the zircon dating of the early Cretaceous basic rock dike group, 12 ages of Gu Yuan from ancient to middle Proterozoic were found in this paper. 1400V 2500Ma). Five Neoproterozoic ages (800 ~ 1400Ma) and four late Paleozoic ages (250 ~ 400MaA); They may reflect the original rock information of different ages of deep basement. It is inferred that there may be "Cathaysian paleocontinent" basement, Caledonian fold belt and late Paleozoic sedimentary caprock. According to the statistical analysis of the "tectonic sheet physicochemical" zone, the paleotectonic stress fields can be divided into two periods. It mainly corresponds to the developing period of the physical and chemical belts in the NE and NW directions, respectively. The main compressive stress of the former is in the direction of S E N W, which is the main tectonic formation period from the middle and late Jurassic to the early Cretaceous. The main compressive stress of the latter is in the direction of NW-NE, mainly in late Cretaceous.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P548

【相似文献】