摘要:银额盆地是中亚造山带南缘的一个中-新生代沉积盆地。在2017～2018年的野外地质调查期间，我们在银额盆地及周缘发现了多处晚新生代的伸展构造。这些伸展构造主要是一系列的正断层，还有同期的“X”共轭节理。相邻的两条倾向相对的正断层形成地堑。杭乌拉南正断层和鼎新镇北地堑形成于第四纪晚期，北山煤矿的正断层活动时间可能也是第四纪晚期。第四纪晚期正断层走向近E-W；伴生的鼎新镇北“X”共轭节理由走向NE-SW和NW-SE两组近直立的节理组成。苏宏图背斜上发育的正断层形成于新近纪晚期—第四纪早期，走向近E-W。古应力场分析，两期伸展构造的最大主拉张应力方向都是近N-S。这两期晚新生代伸展构造属于喜马拉雅碰撞造山的远程效应的组成部分，代表了远程效应脉动式演化过程的两个构造间歇期。
关键词: 伸展构造/
第四纪晚期/
新近纪晚期—第四纪早期/
喜马拉雅碰撞造山远程效应/
构造间歇期??? 银额盆地/
中亚造山带
Abstract:Yingen-Ejinaqi Basin, Yin-E Basin for short, is a Meso-Cenozoic basin on the southern margin of the central Asian orogenic belt. Late Cenozoic extensional structues were revealed at several places in and around the Yin-E Basin during our 2017～2018 field geological investigations. They are mainly normal faults. Two normal faults dipping to each other form a graben. An X-type conjugate cleavage system was found in the granite located north to Dingxin Town. The normal fault located south to Hangwula and the garaben located north to Dingxin Town were formed in Late Quaternary. The normal fault found at Beishan coal-mine was possiblly also formed in Late Quaternary. These Late Quaternary and possible Late Quaternary normal faults strike in E-W direction. The conjugate cleavage system found in the granite located north to Dingxin Town is possile contemporanous structure of the Late Quaternary normal faults. It is constituted by two groups of cleavages striking NE-SW and NW-SE with very high dip angle. The normal faults on the Suhongtu anticline were formed in Late Neogene-Early Quaternary. They strike in E-W direction. Acient stress analysis, the maximum tensional stress of both the Late Quaternary and Late Neogene-Early Quaternary extentional structure is in N-S direction. The Late Cenozoic extensional structures are components of the far-field effect of the India-Asia collision. These two extensional deformation phases represent two tectonic pauses under the far-field effect of the India-Asia collision.
Key words:Extensional structures/
Late Quaternary/
Late Neogene-Early Quaternary/
Far-field effect of the India-Asia collision/
Tectonic pause/
Yingen-Ejinaqi （Yin-E） Basin
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