地质学报2025，Vol.99Issue(12)：4053-4070,18.DOI:10.19762/j.cnki.dizhixuebao.2025186
鄂尔多斯盆地燕山期不整合面类型及分布特征
Types and distribution characteristics of Yanshanian unconformities in the Ordos basin
摘要
Abstract
The Yanshanian Period represents a unique and significant Mesozoic tectonic event in eastern China and the wider East Asian region.In the North China Platform,it is mainly manifested as a regional unconformity.Based on outcrop,drilling,and new seismic data,this study analyzes the identification marks,types,and distribution of unconformities formed during the Yanshanian Period in the Ordos basin.The results show that:① Yanshanian Period unconformities in the Ordos basin are divided into phases(Acts Ⅰ～Ⅳ).② The parallel unconformity surface of Act Ⅰ,resulting from the first phase of the Yanshanian Movement at the end of the Early Jurassic,exists between the Middle Jurassic Zhiluo and Yan'an Formations in localized areas.③ The Yanshanian Movement Acts Ⅱ-Ⅲ at the end of the Middle Jurassic caused uplift in the eastern part of the basin and intense compressional orogeny in the west.This resulted in widespread Acts Ⅱ-Ⅲ unconformities,primarily disconformities,between the Middle Jurassic and Lower Cretaceous strata,with angular unconformities present on the western and southern margins of the basin.④ The Yanshanian Movement Act Ⅳ at the end of the Early Cretaceous led to continued uplift of the eastern part of the basin,which even extended into the central part.Subsequent erosion formed the Act Ⅳ unconformity,dominated by low-angle unconformities between the Lower Cretaceous and the Cenozoic strata,with high-angle unconformities observed on the western and southern margins of the basin.These angular unconformities are categorized into three types:"truncation(lower)to conformity(upper)","conformity(lower)to onlap(upper)",and"truncation(lower)to onlap(upper)".The stratigraphic hiatus across the Acts Ⅱ-Ⅲ unconformities is approximately 6～22 Ma,while the hiatus across the Act Ⅳ unconformity is about 50～120 Ma.During the Jurassic and Cretaceous periods,the overall paleogeomorphology of the Ordos basin was characterized by inherited uplift in its eastern and southern parts,which experienced multiple episodes of unconformity development.关键词
燕山运动/中生代/不整合面/时空分布/构造特征/鄂尔多斯盆地Key words
Yanshanian Movement/Mesozoic/unconsolidated surfaces/temporal spatial distribution/tectonic features/Ordos basin引用本文复制引用
LIU Hao,HE Dengfa,MAO Danfeng,ZOU Song..鄂尔多斯盆地燕山期不整合面类型及分布特征[J].地质学报,2025,99(12):4053-4070,18.基金项目
本文为中国石油长庆油田公司科学研究与技术开发项目(编号2024D1JC06-01)资助的成果. （编号2024D1JC06-01）
