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四川盆地晚二叠世经历了克拉通内裂陷作用以及基底断裂活动,在区域大缓坡背景下,形成“三隆三凹”的古地理格局,发育鄂西—城口海槽、开江—梁平海槽以及盐亭—潼南海槽。在区域背景及动力学分析的基础上,利用钻井、露头、地震资料等论证了盐亭—潼南海槽的几何形态,盐亭—潼南海槽发育在川中地区,整体呈北西-南东向近平行于开江—梁平海槽展布,向西北部广海开口,向东南台地区逐渐变浅并与鄂西—城口海槽连通。利用地震、地质结合的方法,探讨了盐亭—潼南海槽的沉积格局,其以细粒沉积为主,地层厚度薄,其西侧磨溪—中江台缘带以发育生屑滩为主,东侧广安—公山庙台缘带以发育生物礁为主;生物礁滩的分布随着海平面变化具有明显的迁移特征,整体上可以分为两期,并逐渐由两侧台缘带向海槽内迁移。盐亭—潼南海槽的形成、发展及消亡主要受勉略洋扩张-收缩的影响;晚二叠世勉略洋扩张期,四川盆地NW向基底断裂活动,导致川中地区正断活动,形成断陷海槽,即盐亭—潼南海槽。
The Late Permian in the Sichuan Basin underwent the craton and the basement faulting activities. Under the background of large regional gentle slope, the paleogeographic pattern of “Sanlong Sancai” was formed and the western Hubei-Chengkou Trough was developed. - Liangping trough and Yanting - Tongnan trough. On the basis of regional background and dynamic analysis, the geometry of Yanting-Tongnan Trough is proved by drilling, outcrop and seismic data. The Yanting-Tongnan Trench is located in the central Sichuan Basin, with an overall NW-SW direction Parallel to the Kai River - Liangping Trough distribution, to the northwestern Guanghai openings, gradually southeast to Taiwan area and with western Hubei - Chengkou Trough connectivity. The sedimentary pattern of Yanting-Tongnan trough is discussed by means of seismic and geological combination. The sedimentary pattern is mainly composed of fine-grained sediments and the thickness of the formation is thin. The margin of Guang’an-Gongsamiao in the east is dominated by developmental reefs. The distribution of reef-shoal banks has obvious migration characteristics with sea-level change. It can be divided into two phases as a whole, Migration within the trough. The formation, development and demise of Yanting-Tongnan Trough are mainly affected by the expansion and shrinkage of Mianxuelian Ocean. During the Late Permian Mian-LORO expansion, NW-trending basal faults in the Sichuan Basin lead to the normal faulting in the central Sichuan Basin, Trap trough, that is salt Pavilion - Tongnan trough.