CAJ | 학술논문

下侏罗统是四川盆地原油勘探的主力层系，研究其构造-沉积环境与原型盆地演化可为油气勘探奠定重要基础。从周缘构造环境、盆地构造沉降、盆-山耦合作用等出发，结合沉积相研究，将盆地沉积充填演化与周缘造山带演化有机结合，重建了四川盆地及邻区早侏罗世各沉积期构造-沉积环境，并探讨了盆地性质及演化规律。早侏罗世四川盆地构造动力学环境经历了强、弱伸展的交替变化，构造沉降经历了快速→缓慢→稳定的变化特征。自流井组珍珠冲段沉积期为强伸展期，于晚三叠世的断陷-坳陷盆地之上开始稳定的坳陷盆地沉积；自流井组东岳庙段沉积期为弱伸展期，盆缘隆升和基底沉降减慢，促进了岩相和岩性都比较稳定的大规模湖相沉积；自流井组马鞍山段沉积期为强伸展期，盆-岭、盆-山构造耦合作用加强，促进了盆地西缘、北缘以粗碎屑为主的辫状河和大型扇体的发育；自流井组大安寨段沉积期为伸展作用最弱、造山带活动最稳定的时期，盆地整体的拗陷速率远大于陆源碎屑的堆积速率，导致了四川盆地早侏罗世最大湖盆的形成。早侏罗世四川盆地及邻区主体为陆内弱拉张环境下的大型克拉通内坳陷盆地，周缘造山、造陆的间歇性活动，湖盆或快或慢的沉降以及局部的古隆起、古坳陷控制着沉积中心整体向盆地北部及NE方向迁移，其演化过程对油气聚集产生了深远的影响。
하주라통시사천분지원유감탐적주력층계，연구기구조-침적배경여원형분지연화가위유기감탐전정중요기출。종주연구조배경、분지구조침강、분-산우합작용등출발，결합침적상연구，장분지침적충전연화여주연조산대연화유궤결합，중건료사천분지급린구조주라세각침적기구조-침적배경，병탐토료분지성질급연화규률。조주라세사천분지구조동역학배경경력료강、약신전적교체변화，구조침강경력료쾌속→완만→은정적변화특정。자류정조진주충단침적기위강신전기，우만삼첩세적단함-요함분지지상개시은정적요함분지침적；자류정조동악묘단침적기위약신전기，분연륭승화기저침강감만，촉진료암상화암성도비교은정적대규모호상침적；자류정조마안산단침적기위강신전기，분-령、분-산구조우합작용가강，촉진료분지서연、북연이조쇄설위주적변상하화대형선체적발육；자류정조대안채단침적기위신전작용최약、조산대활동최은정적시기，분지정체적요함속솔원대우륙원쇄설적퇴적속솔，도치료사천분지조주라세최대호분적형성。조주라세사천분지급린구주체위륙내약랍장배경하적대형극랍통내요함분지，주연조산、조륙적간헐성활동，호분혹쾌혹만적침강이급국부적고륭기、고요함공제착침적중심정체향분지북부급NE방향천이，기연화과정대유기취집산생료심원적영향。
Lower Jurassic is the main stratum for oil exploration in Sichuan Basin.Research on its tectonic-depositional environment and evolution of prototype basins lays an important foundation for oil and gas exploration.Based on the analysis of peripheral tectonicenvironment,tectonic subsidence and basin-mountain coupling process,and research of sedimentary facies,the tectonic-depositional environment of Early Jurassic in Sichuan Basin and adjacent areas is dynamically reconstructed by integrating the evolution of periph-eral orogenic belts with sedimentary filling evolution,and then basin properties and evolution law are also explored.Tectonic dynamic conditions have experienced intense and weak extensional activities alternatively in the Early Jurassic Sichuan Basin.The tectonic subsidence has undergone fast,slow and stable development period.The deposition stage of Zhenzhuchong Member,Ziliujing For-mation is an intense extension period,during which a stable down-warped deposition began in the Late Triassic fault-depression basin.During the weak extension period of Dongyuemiao Member,Ziliujing Formation the uplift of basin edge and basement subsidenceslowed down,thus promoting the large-scale deposition of lacustrine facies with relatively stable lithofacies and lithological character-istics.The deposition stage of Ma'anshanMember,Ziliujing Formation is another intense extension period.The enhanced basin-ridgeand basin-mountain coupling accelerated the development of braided river and large fan body with coarse clastics in western andnorthern edges of Sichuan Basin.Moreover,the deposition stage of Da’anzhai Member,Ziliujing Formation is the weakest extensionperiod,in which orogenic belts were not active;as a whole,basin depression rate was far greater than the accumulation rate of terrigenous clastics,and thus led to formation of the largest lake basin in the EarlyJurassic Sichuan basin.It is considered that the Ear-ly Jurassic Sichuan Basin and adjacent areas is a large intracratonic depression basin under weak intracontinental extension.The dep-ocenter moves northward and northeastward during the four deposition stages,which is controlled by the intermittent activities of peripheral orogenic and epeirogenic belts,slow and fast depression of lake basin,and local paleo-highs and paleo-depressions.This evolution process has a significant influence on oil and gas accumulation in Sichuan Basin.