四川盆地灯影组三段混积特征及其地质意义

四川盆地灯影组三段混积现象较发育。以川中高科1井、川北杨坝剖面和宁强高家山剖面作为研究对象，通过剖面实测、岩芯观察及薄片鉴定，对四川盆地灯影组三段的混合沉积特征进行了对比研究。研究结果表明:灯影组三段混积岩主要为纹层状泥晶白云岩、纹层状含砂白云岩、含砂白云岩、砂质白云岩以及砂岩等，发育混积型碎屑岩、混积型碳酸盐岩以及高度混积岩三类；混合沉积类型为复合式混合沉积Ⅱ类。四川盆地灯影组三段混积作用受控于气候条件、构造运动、水动力条件、海平面升降以及物源供给等众多因素，且它们互相影响，共同作用。结合混积类型、混积强度以及沉积环境等因素，建立了灯影组三段的混积陆棚模式，指示其陆源碎屑系风暴流等从汉南古陆携带而来，侧面证明灯三段沉积时期，汉南古陆已发生隆起，为四川盆地提供陆源碎屑，这为恢复四川盆地灯影组沉积构造格局提供了参考。

Mixed Sedimentary Characteristics of the Third Member of Dengying Formation,Sichuan Basin,and Its Geological Significance

A three-stage mixing phenomenon in the Dengying Formation, Sichuan Basin, is clearly developed. This study considered the Chuanzhong Gaoke 1 Well and Chuanbei Yangba and Ningqiang Gaojiashan sections. The mixed sedimentary characteristics of the third member of the Dengying Formation were studied by detailed section measurements, core observation and thin-section identification. It was found that the three-stage mixed rock in the Dengying Formation mainly comprises stratiform layered muddy dolomite, stratified sand-bearing dolomite, sand-bearing dolomite, sandy dolomite and sandstone, etc., and the development of mixed types of clastic and carbonate rocks and highly mixed rock(composite mixed sediments Ⅱ). The mixing was controlled by the interaction of many factors:climatic conditions, tectonic movement, hydrodynamic conditions, sea level rise and sediment supply. Combining the factors of mixing type and intensity together with the sedimentary environment, a mixed shelf sedimentary model was established. This indicated terrestrial debris system storm flow from the ancient Hannan land which was uplifted and became the source of terrestrial debris in the Sichuan Basin. This finding provides a reference for restoring the sedimentary and tectonic patterns of the Dengying Formation.