二连盆地脑木根凹陷早白垩世构造变形及演化过程  

Early Cretaceous Structural Deformation and Evolutionary Process in Nomgen Sag, Erenhot Basin

作　　者：徐强 Xu Qiang(Exploration and Research Institute,CNACG,Beijing 100039)

机构地区：[1]中国煤炭地质总局勘查研究总院,北京100039

出　　处：《中国煤炭地质》2022年第3期31-37,共7页Coal Geology of China

基　　金：中国煤炭地质总局科技创新项目(ZMKJ-2020-J03-1);国家能源局项目“国家大型煤炭基地开发潜力研究”;中国煤炭地质总局勘查研究总院青年基金项目(ZGMDKZ-Y-201902(ZY))。

摘　　要：脑木根凹陷位于二连盆地乌兰察布坳陷中部,富含煤炭、石油、铀矿等多种矿产资源。通过总结前人研究成果,结合地震地质与钻井等资料归纳二连盆地早白垩世凹陷复合类型,分析脑木根凹陷断陷构造特征,研究其构造演化过程。主要得到以下认识:①二连盆地早白垩世主要发育串联式、并联式、斜列式及交织式4类断陷复合类型,以串联式和并联式最为发育。脑木根凹陷总体呈现串联式,局部表现为并联式,且沿走向断陷极性发生转变。②下白垩统经历早期开始沉降,中期快速沉降,晚期缓慢沉降三个构造沉降阶段,不同构造带呈现出明显的差异沉降。③早白垩世经历裂陷期及裂陷-坳陷转换期,K_(1)a沉积时期初始裂陷,主边界断层控制地层沉积,凹陷初具半地堑雏形;K_(1)t_(1)沉积时期,裂陷作用增强,断层明显控制地层沉积,凹陷整体呈半地堑;K_(1)t_(2)沉积时期,裂陷作用减弱,地层沉积受断层控制作用减弱;K_(1)s沉积时期,裂陷活动基本停止,裂陷过程结束。The Nomgen sag is situated in the middle part of Ulanqab depression,Erenhot Basin.The sag is rich in coal,oil and uranium etc various mineral resources.Through the summary of previous research findings combined with seismogeological and drilling data have summarized Erenhot Basin early Cretaceous depression composite types,analyzed Nomgen sag fault depression features,studied its structural evolutionary process.Following knowledges have been acquired:①In the Erenhot Basin,early Cretaceous has mainly developed serial,parallel,in echelon and interlocking four fault depression composite types,yet serial and parallel types are most developed.Nomgen sag presents serial type,locally parallel type and the polarity of the fault depression changes along the strike.②Lower Cretaceous in the area has experienced early-stage initial subsiding,mid-term fast subsiding and later period slow subsiding three tectonic subsiding stages;in different structural belts present obvious differential subsiding.③Early Cretaceous has experienced rifting stage,rifting-depressing transition stage,during the K_(1)a sedimentary period,rifting initiated,the main boundary fault controlled strata deposition,sag at the beginning half-graben embryonic form;during the K_(1)t_(1) sedimentary period,rifting enhanced,fault had obviously controlled strata deposition,sag overall presented half-graben;during the K_(1)t_(2) sedimentary period,rifting weakened,strata deposition fault-controlling weakened;during the K_(1)s sedimentary period,lifting basically stopped,lifting process ended.

关 键 词：早白垩世构造 构造演化 脑木根凹陷 二连盆地 

分 类 号：P542[天文地球—构造地质学]