试论江西的地壳运动

地壳运动是现代地质科学研究中的一个重大课题。历来是地质科学联系实际的重大基础理论问题之一,也是地质工作,特别是区域地质调查研究工作经常遇到而又必须解决的关键问题之一。正确地鉴定地壳运动时期及其性质,合理地划分构造旋迴及其幕次,具体

CRUSTAL MOVEMENTS IN JIANGXI

Since the Proterozoic Jiangxi has experienced several strong crustal movements,of which the Jinningian,Caledonian,Indosinian and Yanshanian movements are the strongest. According to integrated geological-structural factors such as sedimentation,magmatism,metamorphism,structural deformation and contact relationships between the strata,four tectonic cycles（i.e. the Jinningian,Chengjiangian-Caledonian,Variscan-Indosinian and Yanshanian-Himalayan tectonic cycles）,six tectonic subcycles and fourteen main tectonic episodes may be largely distinguished. Through a preliminary study,it is considered that the Sichuanian movement occurring between the late Cretaceous and the early Tertiary is not pronounced in Jiangxi; but there is a distinct angular unconformity between the Nanxiong Formation in the upper part of the upper Cretaceous and the Ganzhou Formation in the lower part. Therefore,this unconformity should represent the last episode of the Yanshanian movement or the Yanshanian subcycle as well as the upper limit thereof. The lower limit of the Yanshanian movement or the Yanshanian subcycle should be placed at late Triassic. For the relationships between the tipper Triassic Anyuan Formation and the lower Jurassic Linshan Formation are mostly expressed by parallel unconformities and,in some areas,continuous transition; both belong to the same type of formation and their magmatism and tectonic deformation are mostly similar. The upper limit of the Indosinian movement or the Indosinian subcycle should be placed at terminal middle Triassic. For the upper Triassic and the middle Triassic both not only show a contact of angular unconformities,but also are quite different in type of sedimentary formation and features of tectonic deformation. The lower limit of the Indosinian movement or the Indosinian subcycle should be shifted down to the boundary of the Dongwuian movement of earliest late Permian age; for the relationships between the lower middle Triassic and the upper Permian are continuously transional. Since the Meso-Cenozoic,there have mainly occurred tectonic deformations represented by dominantly NE-or NNE-trending fault-block uplifts and depressions.