南盘江盆地及邻区早中三叠世层序地层格架及其古地理演化——兼论从“滇黔桂盆地”到“南盘江盆地”的演变过程  

Sequence-Stratigraphic Framework of the Early to Middle Triassic and Evolution of Sedimentary-Facies and Paleogeography in the Nanpanjiang Basin and Its Adjacent Areas: Discussion on Evolutionary Process from the Dianqiangui Basin to the Nanpanjia

作　　者：梅冥相[1] 马永生[1] 邓军[1] 孟庆芬[1] 易定红[1] 李东海[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083

出　　处：《高校地质学报》2003年第3期427-439,共13页Geological Journal of China Universities

摘　　要：二叠纪与三叠纪之交的大规模台地淹没事件使二叠纪时期的一些孤立台地被淹没而消亡,其后,研究区在三叠纪经历了从滇黔桂盆地到南盘江盆地的演化过程;在空间上,从连陆台地到浊积盆地以及发育在浊积盆地中的孤立碳酸盐台地,相分异特别明显,特别是南宁和靖西一带孤立台地上早三叠世的鲕粒滩以及连陆台地边缘的礁滩相灰岩更是引人注目。尽管不同相带的三级沉积层序相序组构千差万变并且它们的形成时限也不尽相同,但是由其所表征的相对海平面变化则具有大致的同步性,从而在早中三叠世地层中可以识别出6个三级沉积层序;以地层记录中的两种相变面和两种穿时性为基本要素,即可以建立南盘江盆地早中三叠世的层序地层格架。早、中三叠世层序地层格架及相应的古地理特征,代表了统一的南盘江盆地的形成演化过程;晚三叠世的古地理特征,反映了南盘江盆地的消亡过程。A large-scale drowning event occurred in the transitional period between the Permian and the Triassic and resulted in the demise of some carbonate platforms in the Nanpanjiang Basin and its adjacent areas. The research areas experienced an evolutionary process of sedimentary basin from the Dianqiangui Basin to the Nanpanjiang Basin in the Triassic. Accordingly, the Triassic period is a differential period of sedimentary facies in the research areas, which are marked by the spatial changes from the connective platforms to the turbidity basin with the development of the several isolated platforms. More particularly, oolitic banks of the early epoch are developed in some isolated platforms such as in the Jingxi platform and in the Nanning platform in the southern part of the Nanpanjiang Basin. Same as the limestones of reef and beach in the margin of the attached platform, the limestones of oolitic banks in isolated platforms came to front. Despite the differences in the time-span and the architecture of facies-succession of third-order sedimentary sequences, the process of the third-order relative sea-level changes reflected by the sedimentary-facies succession is generally synchronous. Therefore, six third-order sequences could be discerned in the Early and the Middle Triassic in the Nanpanjiang Basin. With the two types of facies-changing surfaces and two types of diachronisms in stratigraphic records as the key elements, the framework of sequence stratigraphy from the Early to the Middle Triassic in the Nanpanjiang Basin could be constructed. The sequence-stratigraphic framework and the relevant paleo-geographical features of the Early to Middle Triassic reveal the formational and the evolutionary process of the Nanpanjiang Basin, and the paleogeographical features of the Late Triassic reflect the dying of the Nanpanjiang Basin. In the research areas, the Early Triassic can be grouped into three third-order sequences, SQ1, SQ2 and SQ3. The forming process of SQ1 represents a building process of a ramp

关 键 词：层序地层格架 古地理演化 早中三叠世 南盘江盆地 

分 类 号：P531[天文地球—古生物学与地层学]