天然气勘探与开发2025，Vol.48Issue(5)：14-24,11.DOI:10.12055/gaskk.issn.1673-3177.2025.05.002
鄂尔多斯盆地西缘酸枣子沟剖面蓟县系沉积特征
Sedimentary characteristics of Jixian System in Suanzaozigou section,western margin of Ordos Basin
摘要
Abstract
To clarify the sedimentary characteristics and evolution patterns of the transition zone from open platforms to tidal flats in the middle segment of the western margin of the Ordos Basin,the Mesoproterozoic Jixian System in the Suanzaozigou section of Tongxin County was selected for detailed study.It involved stratigraphic section measurement,systematic thin section microscopic observations,trace element analysis,stable carbon-oxygen isotopes determination,and comprehensive sedimentological investigation.The types of sedimentary microfacies and their vertical evolution characteristics in the study area were identified,and the combination patterns of different sedimentary microfacies were established.The results show that,(i)the rock types of the Jixian System include stromatolitic dolomite,granular dolomite(predominantly arenitic),crystalline dolomite,and siliceous dolomite;stromatolites exhibit mainly horizontal,mound-shaped and wavy morphologies,lacking large-scale columnar ones;(ii)there develops vertically stromatolite assemblages such as horizontal-mound-shaped,wavy-mound-shaped,and horizontal-wavy-mound-shaped,confirming that they were formed in intertidal to supratidal depositional environments under weak hydrodynamic conditions with high-frequency sea-level fluctuations;(iii)discrimination based on environmental proxies and carbon-oxygen isotopes suggests that the study area was characterized by weakly oxidizing,hot and arid paleoclimatic and paleo-oceanic environments;and(iv)vertical sequence analysis reveals the sedimentary microfacies dominated by supratidal zones,grain banks,and minor intertidal zones,indicating a transition from tidal flats intercalated with grain banks under weak hydrodynamics in the early stage to interlaminated grain banks and tidal flats with alternating strong and weak hydrodynamics during the middle-late stages.It is concluded that the sedimentary characteristics of the Jixian System in the Suanzaozigou section reflect the rapid facies changes and narrow facies belts of the Mesoproterozoic open platform to tidal flat transition zone in the western margin of the basin.The sedimentary evolution is primarily controlled by high-frequency sea-level fluctuations.关键词
叠层石/颗粒滩/白云岩/潮坪/沉积特征/中元古界蓟县系/鄂尔多斯盆地西缘Key words
Stromatolite/Grain bank/Dolomite/Tidal flat/Sedimentary characteristics/Mesoproterozoic Jixian System/Western margin of Ordos Basin分类
能源科技引用本文复制引用
刘宏宇,景译萱,刘喜欢,李文昌,杨康,张乾,雷微微,张云峰..鄂尔多斯盆地西缘酸枣子沟剖面蓟县系沉积特征[J].天然气勘探与开发,2025,48(5):14-24,11.基金项目
国家自然科学基金面上项目"埋藏期去白云石化机制及储集意义"(编号:42272181). （编号:42272181）
