地球学报2026，Vol.47Issue(3)：597-612,16.DOI:10.3975/cagsb.2025.090221
鄂尔多斯盆地西南部早白垩世岩浆事件及其地质意义
Early Cretaceous Magmatic Events in the Southwestern Part of the Ordos Basin and Their Geological Significance
摘要
Abstract
Cretaceous magmatic events in the Ordos Basin are crucial for unraveling the regional tectonic dynamic evolution mechanisms of the Early Cretaceous and exploring the spatiotemporal coupling relationships between magmatism,hydrocarbon accumulation,and sandstone-type uranium mineralization.This study identified,for the first time,Early Cretaceous intrusive rocks within the Lower Cretaceous Huanhe-Huachi Formation in the southwestern part of the Ordos Basin.Integrated petrological,zircon U-Pb geochronological,and Hf isotopic analyses were conducted.A melanocratic porphyry intrusive body is identified in the Huanhe-Huachi Formation,yielding a zircon U-Pb weighted mean age of(126.5±0.9)Ma(MSWD=1.6),indicating the middle Early Cretaceous magmatism.Zircon εHf(t)values of-12.32--4.70,and TDM2 model ages of 1 960-1 501 Ma indicate that this region records the Early Cretaceous magmatic activity of the westernmost North China Craton.The magmatic ages decrease eastward and westward from the Taihang-Lüliang tectonic belt,reflecting an extensional setting jointly controlled by the westward subduction of the Paleo-Pacific Plate and the northeastward subduction of the Bangong-Nujiang Ocean.Asthenospheric upwelling triggered lithospheric thinning and the partial melting of the ancient crust,forming a mantle heat-driven magmatic system.Magmatic thermal effects promoted hydrocarbon generation and expulsion in deep-source rocks.The released reducing agents participated in redox interface regulation for shallow sandstone type uranium mineralization,although magmatic-hydrothermal fluids did not directly contribute to uranium ore-forming processes.关键词
鄂尔多斯盆地/早白垩世岩浆活动/锆石U-Pb定年/Hf同位素/板块俯冲Key words
Ordos Basin/Early Cretaceous magmatism/zircon U-Pb dating/Hf isotopes/plate subduction分类
天文与地球科学引用本文复制引用
陈印,田德强,徐喆,吴兆剑,张羽,张博..鄂尔多斯盆地西南部早白垩世岩浆事件及其地质意义[J].地球学报,2026,47(3):597-612,16.基金项目
本文由中广核铀业发展有限公司科技项目(编号:CGNPC-URC-T-2024-12)、天津市自然科学基金项目(编号:24JCYBJC00410)和科技部科技基础资源调查专项(编号:2022FY101800)联合资助. This study was supported by the CGNPC Ura-nium Resources Co.,Ltd.(No.CGNPC-URC-T-2024-12),the Tianjin Natural Sci-ence Foundation of China(No.24JCYBJC00410),and the Science&Technology Fundamental Resources Investigation Program of China(No.2022FY101800). （编号:CGNPC-URC-T-2024-12）
