滇西湾甸坝地区下泥盆统向阳寺组地层特征与沉积环境分析

发布时间：2018-07-08 13:45

本文选题：向阳寺组 + 对比分析　；参考：《成都理工大学》2015年硕士论文

【摘要】：研究区在大地构造单元上属冈瓦纳大陆与劳亚大陆之间的特体斯-喜马拉雅构造带(域),东部与兰坪-思茅前陆盆地相邻,中部为扬子西缘多岛-弧盆系昌宁混杂岩带,西部为保山地块东缘;并且是中国西南板块运动学、动力学和板块边缘造山与成岩成矿作用的理想研究场所,具有良好找矿前景。湾甸坝地区向阳寺组属昌宁-孟连带西侧保山-镇康地块的组成部分,地层出露较好,是研究该区早泥盆世沉积环境的良好载体。本文是在云南保山—龙陵地区湾甸坝、勐统街等5幅区域地质矿产调查野外工作的基础上,通过搜集前人对本区和邻区的研究资料以及对本研究区下泥盆统向阳寺组的资料分析研究后完成的。以前人的相关研究为基础,通过对湾甸坝地区下泥盆统向阳寺组地层的对比分析及沉积盆地构造演化的研究,主要取得以下几点认识:(1)查明了湾甸坝地区下泥盆统小新寨和摆榔乡向阳寺组地层分别为碎屑岩-硅质岩建造和碎屑岩-碳酸盐岩建造。(2)根据基准面旋回变化将湾甸坝地区摆榔乡向阳寺组划分为2个长期旋回层序和6个中期旋回层序,小新寨向阳寺组划分为2个长期旋回层序和6个中期旋回层序。(3)通过对向阳寺组地层沉积相标志的综合研究,认为小新寨向阳寺组为浅海陆棚沉积,可进一步识别出浅水陆棚沉积、深水陆棚沉积;摆榔乡向阳寺组为浅海陆棚沉积和碳酸盐岩开阔台地沉积,进一步识别出潮间带、潮下带、浅水陆棚、深水陆棚等多个沉积单元。(4)通过向阳寺组地层对比研究,认为小新寨向阳寺组和摆榔乡向阳寺组属于同物同名,不同水深环境下的沉积;保山地块与镇康地块沉积环境存在差异。(5)综合向阳寺组沉积环境对比分析研究,并结合区域地质特征和构造背景,认为早泥盆世研究区处于海侵阶段,海岸线继续向陆地推进,并且揭示东部更接近海洋的古地理特征。随着前寒武纪末至早古生代初泛大陆解体,古生代时期的保山地块随着原特提斯和古特提斯洋的发育而长期处于被动边缘发展状态,造就了下泥盆统向阳寺组的古地理格局。
[Abstract]:The study area belongs to the Teties-Himalayan tectonic belt (region) between Gondwana and Laoya continents in the tectonic unit. In the east, it is adjacent to the Lanping-Simao Foreland basin, and in the middle is the Changning melange belt of the multi-island-arc basin system in the western margin of Yangtze. The west is the eastern margin of Baoshan massif, and it is an ideal place for studying the kinematics, dynamics and diagenesis of the plate margin in southwestern China, and has a good prospecting prospect. Xiangyangsi formation in Wandianba area is a part of Baoshan-Zhenkang block on the west side of Changning-Menglian belt. It is a good carrier to study the sedimentary environment of early Devonian in this area. This paper is based on the field investigation of five regional geological and mineral resources in Baoshan-Longling area, Yunnan Province, such as Wandian Dam and Mengtong Street. By collecting the previous research data of this area and adjacent areas and analyzing the data of Xiangyangsi formation of Lower Devonian in this study area. On the basis of previous studies, the strata of Xiangyangsi formation of Lower Devonian in Wandianba area were analyzed and the tectonic evolution of sedimentary basins was studied. The main results are as follows: (1) the strata of the Lower Devonian Xiaoxinzhai and Xiangyangsi formation in Wandianba area are respectively clastic rock-siliceous formation and clastic rock-carbonate formation. (2) according to the change of base-level cycle, the formation of Xiaoxinzhai and Xiangyangsi formation is determined. The Xiangyangsi formation of Chuang Nuxiang in Wandianba area is divided into two long-term cyclic sequences and six intermediate cyclic sequences. The Xiaoxinzhai Xiangyangsi formation is divided into two long-term cyclic sequences and six intermediate cyclic sequences. (3) based on a comprehensive study of the sedimentary facies markers of the Xiangyangsi formation, it is considered that the Xiaoxinzhai Xiangyangsi formation is a shallow sea shelf deposit. The shallow water shelf deposits and the deep water shelf deposits can be further identified, and the Xiangyangsi formation in Chuang Qi Township is a shallow sea shelf deposit and carbonate rock open platform deposit, which can further identify the intertidal zone, the subtidal zone and the shallow water shelf. (4) through stratigraphic correlation study of Xiangyangsi formation, it is considered that the Xiangyangsi formation and Xiangyangsi formation belong to the same body with the same name and different water depth environments; The sedimentary environment of Baoshan block and Zhenkang block is different. (5) the comparative analysis of sedimentary environment of Xiangyangsi formation, combined with regional geological characteristics and tectonic background, suggests that the early Devonian study area is in the transgressive stage and the coastline continues to advance to land. It also reveals the paleogeographic features of the east closer to the ocean. With the disintegration of the Precambrian and early Paleozoic pancontinents, the Baoshan block in the Paleozoic period was in the passive marginal development state with the development of the original Tethys and the PaleoTethys oceans, which resulted in the paleogeographic pattern of the Xiangyangsi formation in the Lower Devonian.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P534.44

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