Based on field geological survey, interpretation of seismic reflection profile and thermochronology dating, this paper systematically studied the structural deformation of the Yuqia-Jiulongshan region in northern Qaidam Basin during the Cenozoic. The results show that the area is primarily dominated by a large box-shaped anticline, with steep limbs and a wide and gently-deformed core. The Mahaigaxiu and Jiulongshan anticlines are secondary folds controlled by secondary faults in the limbs of the box-shaped anticline. Whereas the Yuqia and the Northern Yuqia anticlines are secondary folds within the wide core of the box-shaped anticline. The geometry of the box-shaped anticline is mainly controlled by some high-angle reverse faults with certain right-lateral strike-slip components, displaying distinct positive flower structures in section view. Combining the sedimentary correlation and detrital apatite fission track analysis, we believe that the Yuqia-Jiulongshan region was a paleo-uplift that developed slightly in the early Cenozoic, resulting in the relatively thin Cenozoic strata. The intense deformation that shaped the present-day structural framework occurred in or after the sedimentary period of Shizigou Formation. The Yuqia – Jiulongshan paleo-uplift is adjacent to the Sainan depression that is rich in Lower-Middle Jurassic source rocks, and thus has high potential for future hydrocarbon exploration.

本文基于野外地质调查，地震反射剖面解释和热年代学测年，系统地研究了柴达木盆地北部新生代时期的于恰—九龙山地区的构造变形。结果表明，该地区主要以大型箱形背斜为主，肢体陡峭，核心宽而轻度变形。玛格嘎秀和九龙山背斜是由箱形背斜四肢次生断层控制的次生褶皱。于卡和北于卡背斜是盒形背斜宽芯内的次生褶皱。箱形背斜线的几何形状主要由一些具有一定右旋走滑分量的高角度逆断层控制，在剖面图中显示出独特的正花结构。结合沉积相关性和碎屑磷灰石裂变径迹分析，我们认为于恰-九龙山地区是一个古隆起，在新生代早期略有发展，形成了较薄的新生代地层。形成当今结构框架的强烈变形发生在石子沟组的沉积时期内或之后。于恰–九龙山古隆起与塞南凹陷相邻，该塞纳凹陷富含中下侏罗统烃源岩，因此在未来的油气勘探中具有很高的潜力。形成当今结构框架的强烈变形发生在石子沟组的沉积时期内或之后。于恰–九龙山古隆起与塞南凹陷相邻，该塞纳凹陷富含中下侏罗统烃源岩，因此在未来的油气勘探中具有很高的潜力。形成当今结构框架的强烈变形发生在石子沟组的沉积时期内或之后。于恰–九龙山古隆起与塞南凹陷相邻，该塞纳凹陷富含中下侏罗统烃源岩，因此在未来的油气勘探中具有很高的潜力。