摘要
混合沉积是沉积学中一个新的研究领域。四川盆地下奥陶统中广泛发育混合沉积。在前人研究成果的基础上,结合区域地质资料、钻(测)井资料以及岩心观察,重点研究了四川盆地下奥陶统混合沉积的沉积特征、成因类型以及混合沉积发育的控制因素,得到如下认识:1狭义的混积岩主要分布在川西南、川南西部和川中地区,川南东部、川东大部主要以碳酸盐岩与陆源碎屑岩的互层或夹层混合沉积为主。2混积层系的成因类型主要包括渐变型、突变型、复合Ⅰ型、复合Ⅱ型。3混合沉积的发育受多种因素的联合控制,且相互影响。早奥陶世,上扬子地区构造活动较弱,由于海平面的逐渐上升造成物源供给面积的减少;同时偶尔受冷水流的影响,造成桐梓组比红花园组混合沉积更为发育,分布更为广泛。
The mixed sedimentation is a new research field for the sedimentology. The mixed sedimentation develops extensively in the Lower Ordovician of Sichuan Basin.This paper studies the mixed sedimentation in this area based on the regional geological data,the well logging data,and the observation of well cores and 3 conclusions are obtained as follows.（1 ）The mixed sedimentation rocks spread in the southwest,middle of the area.In the rest of the area,lithofacies sequences are characterized by the interbeded mixed deposits of terrigenous clastics rock and carbonate rocks.（2） The genetic types of the mixed sequence is divided into 4 types of gradation,mutation,compound-Ⅰ, and compound-Ⅱ.（3）Many factors control the mixed sedimentation together and affect each other. During the Early Ordovician,tectonic activity in the study area was weak.The gradual increasing of sea level made the supply area of terrigenous detritus decrease and the occasional invasion of cold water inhibited the growing of carbonate platform.These factors make the mixed sedimentation develop more extensive in Tongzi Formation than that in Honghuayuan Formation.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2015年第5期579-588,共10页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
国家科技重大专项(2011ZX05004-001)
关键词
混合沉积
控制因素
下奥陶统
四川盆地
mixed sedimentation
controlling factor
Lower Ordovician
Sichuan Basin
