四川盆地震旦纪-早寒武世构造-沉积演化过程

前人对四川盆地震旦纪-早寒武世构造-沉积演化的认识存在较大分歧.利用最新的地震、钻井及露头资料，系统论述了四川盆地震旦纪-早寒武世构造-沉积演化特征.四川盆地在陡山沱组沉积前呈现隆坳相间地貌格局，汉南古陆构造高点从陡山沱期到早寒武世持续向北东方向迁移；开江-宣汉古隆起灯一、灯二段沉积期为主要发育时期，古隆起核部出露水面，灯三、灯四段沉积期古隆起规模减小，转为水下隆起，到早寒武世与川中古隆起合并.通过连井剖面、典型井元素测井、野外露头特征综合分析认为德阳-安岳古裂陷槽内发育灯三、灯四段深水沉积.在此基础上总结古裂陷发育模式:古裂陷具有明显的多期发育特征，东侧台地边缘不断向北东方向迁移，灯二段沉积期台缘位于双探地区，灯四段沉积期台缘位于元坝西地区；同时古裂陷具有"北早南晚、先断陷后坳陷"的发育特征，灯影组沉积期在川中-川北发育，具有断陷发育特征，早寒武世裂陷槽转为坳陷发育特征，川南地区开始大规模发育，川中-川北地区持续向北东方向迁移，川北元坝-仁和场-马路背地区转化为深水沉积，发育厚层筇竹寺组烃源岩层系，至早寒武世晚期，古裂陷消亡、被填平补齐. 

Sinian-Early Cambrian Tectonic-Sedimentary Evolution in Sichuan Basin

There are many different opinions on Sinian-Early Cambrian tectonic-sedimentary evolution in Sichuan Basin.Based on the previous studies, the latest seismic, drilling and outcrop data and the sedimentary evolution characteristics of Sinian-Early Cambrian tectonics in Sichuan Basin are discussed systematically.The analysis shows that the Sichuan Basin has a structural framework with alternative depressions and upheavals before the deposition of Doushantuo Formation.The high point of the Hannan ancient land structure continued migration to the northeast in the sedimentary period of Doushantuo to Early Cambrian.The Kaijiang-Xuanhan ancient uplift in the first and second phase of Dengying Formation sedimentary period is the main developing period, and the top of the ancient uplift may be no longer covered by water.During the third and fourth phase of Dengying Formation sedimentary period, the development of the ancient uplift decreased and turned into the underwater uplift.In the Early Cambrian period, it merged with the ancient uplift in central Sichuan.Based on the analysis of the well connection profile, typical well element logging, field outcrop characteristics and previous research results, our analysis suggests that there is deep-water deposit in the Deyang-Anyue ancient rifting during the third and fourth phase of Dengying Formation sedimentary period.On this basis, the development pattern of ancient rifting is summarized.The Deyang-Anyue ancient rifting has obvious characteristics of multiple stages of development.The edge of the ancient rifting continues to move northeast, the edge of the ancient rifting of the second phase of Dengying Formation sedimentary period is located in the Shuangtan area, while the edge of the ancient rifting of the fourth phase is located in the west of Yuanba.At the same time, the ancient rifting has the development characteristics of "early in the north and late in the south, first fault depression second depression".The ancient rifting developed from the middle to the north of Sichuan during the sedimentary period of Dengying Formation and had the development characteristics of fault depression.In Early Cambrian, the ancient rifting changed into depression, and the South Sichuan area began to develop on a large scale, the edge of the ancient rifting continues to move northeast in the middle to the north of Sichuan.The hydrocarbon source rock of Qiongzhusi Formation was developed as a result of transformation of Yuanba-Renhechang-Malubei area into deep water deposits in northern Sichuan Basin.By the end of the Early Cambrian, the ancient rift had died out and was filled up.