地质学报2025，Vol.99Issue(12)：4019-4037,19.DOI:10.19762/j.cnki.dizhixuebao.2025246
准噶尔盆地西部地区主要不整合面形成演化与油气地质意义
The formation,evolution,and petroleum geological significance of major unconformities in the western region of the Junggar basin,China
摘要
Abstract
Basedon regional 2D/3D seismic profiles of the Junggar basin,this study systematically investigates five major regional unconformities:the Permian/Carboniferous(P/C),Lower Triassic-Upper Permian/Middle-Lower Permian(T-P3/P2),Jurassic/Triassic(J/T),Cretaceous/Jurassic(K/J),and Paleogene/Cretaceous(E/K).By analyzing their contact relationships and seismic reflection characteristics,and denudation features,the spatial distribution and tectonic genesis of each unconformity are clarified.The results indicate:① Distinct Zonation:the P/C unconformity is developed in the western uplift zone,characterized by the truncation of Carboniferous volcanic rocks and overlying Permian onlap deposits.The T-P3/P2 unconformity is concentrated in the northwestern fault belt,exhibiting typical truncation-onlap characteristics.The J/T and K/J unconformities are distributed across the central uplift areas,dominated by a disconformity in the Luliang uplift,whereas the E/K unconformity has migrated to the northern and southern foreland belts.② Orogeny-controlled formation mechanisms:the P/C angular unconformity was triggered by the Late Paleozoic closure of the West Junggar Ocean(～300 Ma).During the Indosinian(～260 Ma),the remote effect of the Paleo-Tethys closure induced dextral strike-slip and thrusting along the Kebai fault zone,forming the localized T-P3/P2 unconformity.Subsequently,Yanshanian(200～145 Ma)intracontinental collisions led to the formation of the J/T and K/J unconformities.Finally,the Himalayan-stage(～50 Ma)India-Eurasia collision generated high-angle E/K unconformities along the basin margins.③ Triple control on hydrocarbon accumulation:unconformities influence hydrocarbon enrichment through three key mechanisms:reservoir improvement(e.g.,80～120 m of secondary porosity in the P/C weathering crust),hydrocarbon migration pathways(e.g.,lateral transport along J/T surfaces),and reservoir-seal assemblages(e.g.,the Baikouquan sandstone-mudstone configuration).This study provides a geological framework for exploring subtle hydrocarbon reservoirs in the Junggar basin.关键词
准噶尔盆地/不整合面/构造演化/油气成藏/应力场迁移/盆山耦合Key words
Junggar basin/unconformity/tectonic evolution/hydrocarbon accumulation/stress field migration/basin-mountain coupling引用本文复制引用
WEI Xiaosong,YAN Detian,ZHENG Menglin,TANG Yong,ZHANG Lei,XU Shiqi,ILYHAMJAN Tuniyaz,ZHANG Bao,YUAN Duoen..准噶尔盆地西部地区主要不整合面形成演化与油气地质意义[J].地质学报,2025,99(12):4019-4037,19.基金项目
本文为中国石油天然气股份有限公司"十四五"前瞻性基础性重大科技项目(编号2022DJ0108)资助的成果. （编号2022DJ0108）
