地质通报2024，Vol.43Issue(5)：812-826,15.DOI:10.12097/gbc.2023.03.008
四川广元羊木—岩洞地区震旦纪—寒武纪界线地层序列及构造-沉积演化
Stratigraphic sequence and tectonic-sedimentary evolution of Sinian-Cambrian boundary in Yangmu-Yandong area,Guangyuan,Sichuan Province
摘要
Abstract
The formation mechanism and time of the Mianyang-Changniang sag are still controversial,which significantly limit the petroleum exploration of the Dengying Formation.In order to provide a better time constraint on the deep-water strata in the Mianyang-Changning intracratonic sag and deepen the understanding of its tectonic-sedimentary evolution process,this study carries out comprehensive stratigraphic correlation and sedimentary environment analysis of four sections in Guangyuan area,based on outcrop description,thin section observation and carbon isotope analysis.The characteristics of petrology and carbon isotopes show that the four outcrop profiles in the study area can be divided into four lithologic units from bottom to top(namelyⅠ,Ⅱ,Ⅲ and Ⅳ).Lithologic unitⅠis composed of thin-bedded argillaceous limestone intercalated with argillaceous dolomite band,which is equivalent to the 3rd Member of the Doushantuo Formation with the Shuram-Wonoka negative δ13C excursion.Lithologic unit Ⅱis represented by black shale,corresponding to the 4rd Member of the Doushantuo Formation.Lithologic unit Ⅲ showing the transition from massive dolomite to chert,can be correlated with the Dengying Formation.Lithologic unit Ⅳ is marked by platy chert,which is equivalent to the Maidiping Formation.Of these,during the early stage of the second member of Dengying to Maidiping period,massive dolomite shifted to thin-bedded chert with slump breccias and fold deposited in the study area,indicating rapid evolution from carbonate platform to slope-basin depositional environment.This deepening depositional trend is opposite to the shallowing to exposure of the whole Middle-Upper Yangtze platform,indicative of rapid subsidence induced by extensional faulting.关键词
绵阳-长宁拉张槽/广元地区/灯影组/地层对比/构造-沉积演化Key words
Mianyang-Changning intracratonic sag/Guangyuan area/Dengying Formation/stratigraphic correlation/tectonic-sedimentary evolution分类
天文与地球科学引用本文复制引用
王林康,唐攀,陈荣庆,丁一,文龙,李智武,刘树根,陈代钊,宋金民,王瀚,陈明思,杨钹..四川广元羊木—岩洞地区震旦纪—寒武纪界线地层序列及构造-沉积演化[J].地质通报,2024,43(5):812-826,15.基金项目
国家自然科学基金项目《上扬子地区埃迪卡拉纪灯影期碳酸盐岩台地氧化还原状态及演化》(批准号:41902105)和《海相深层油气富集机理与关键工程技术基础研究》(编号:U19B6003) （批准号:41902105）
