Abstract The Huoerguosi-Manasi-Tugulu fold-and-thrust belt, which is located in the southern Junggar Basin, has formed in response to contraction during Late Cenozoic. However, the tectonic environment for its formation before Late Cenozoic is still controversial. In this paper, we use surface data, recently collected and processed subsurface seismic refection data, isopach map of Lower Jurassic and balanced sections to propose pre-existing half-graben system developed in the Lower Jurassic with this fold-and-thrust belt. We also use results of a series of scaled sandbox analogue models, where industrial CT apparatus was used to monitor deformation, to simulate the evolution of this fold-and-thrust belt. We suggest that the segmented shape of the Huoerguosi-Manasi-Tugulu fold-and-thrust belt is a response to the presence of thrust ramps, which were formed during Early Jurassic. During Late Cenozoic shortening, the Lower Jurassic syn-rift sediments served as major detachment horizon, making a pre-existing normal fault act as a stress concentration zone leading to steeping of a thrust-ramp over the normal fault and cover detachment overstep the underlying half-grabens. Modeling results reveal that the presented structural framework has close resemblance with paleostructures especially in the intracontinental environment, which underwent a complex multicycle evolution process, and provide a new prospective for the interpretation of natural examples.

中文翻译：

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深部半地堑在北天山霍尔果斯-玛纳斯-吐古鲁褶皱冲断带演化中的作用

摘要 位于准噶尔盆地南部的霍尔果斯-玛纳斯-吐古鲁褶皱冲断带是晚新生代收缩响应形成的。但其形成于晚新生代之前的构造环境仍存在争议。在本文中，我们利用地表数据、最近收集和处理的地下地震反射数据、下侏罗统等厚图和平衡剖面，提出了在下侏罗统利用该褶皱冲断带发育的预先存在的半地堑系统。我们还使用一系列按比例缩放的沙箱模拟模型的结果，其中工业 CT 设备用于监测变形，以模拟该褶皱和推力带的演变。我们认为，霍尔果斯-玛纳斯-吐古鲁褶皱冲断带的分段形状是对逆冲斜坡存在的响应，形成于早侏罗纪。在晚新生代缩短期间，下侏罗统同裂谷沉积物作为主要的拆离层位，使先前存在的正断层成为应力集中区，导致正断层上的逆冲斜坡陡峭，覆盖层拆离越过下伏的一半-地堑。建模结果表明，所提出的构造格架与古构造非常相似，尤其是在陆内环境中，经历了复杂的多旋回演化过程，为自然实例的解释提供了新的前景。使预先存在的正断层充当应力集中区，导致正断层上的逆冲斜坡陡峭，覆盖层脱离下伏的半地堑。建模结果表明，所提出的构造格架与古构造非常相似，尤其是在陆内环境中，经历了复杂的多旋回演化过程，为自然实例的解释提供了新的前景。使预先存在的正断层充当应力集中区，导致正断层上的逆冲斜坡陡峭，覆盖层脱离下伏的半地堑。建模结果表明，所提出的构造格架与古构造非常相似，尤其是在陆内环境中，经历了复杂的多旋回演化过程，为自然实例的解释提供了新的前景。