The Liupanshan Basin constitutes a major portion of the northern North-South tectonic belt. The Lower Cretaceous strata in the Liupanshan Basin recorded the tectono-sedimentary evolution processes of this area and are pivotal for understanding the original sedimentary appearance of the Liupanshan Basin. In this work, we present a study of provenance and tectono-sedimentary evolution of the Liupanshan Basin during the Early Cretaceous. Integrated-paleocurrent directions, gravel clast compositions, and detrital zircon U-Pb isotopic analysis of the Lower Cretaceous Sanqiao and Heshangpu formations were applied to determine the provenance. The gravel clast compositions of Sanqiao Formation conglomerates (mainly including magmatic rocks, metamorphic rocks and limestones) display various features in different places, revealing different rock components of source areas. The paleocurrent directions of the Sanqiao and Heshangpu formations suggest that the sediments were transported from the basin margin to the center. Detrital zircons of two samples from the Huoshizhai Section (northwestern Liupanshan Basin) yield a dominant unimodal distribution from 420 to 500 Ma, suggesting a single-sourced provenance. Based on the above analyses, comparing to the magmatic records in the Qilian-Qinling orogenic belt, the detritus of the Sanqiao and Heshangpu formations were mainly from the proximal metamorphic and magmatic rocks of the Qilian-Qinling orogenic belt and the limestones of the archaic uplift. Combined with sedimentary characteristics, we concluded that the Liupanshan Basin experienced multi-stage evolution history: (1) the early rifting extension stage (Sanqiao Period), (2) the middle spanning and depression stage (Heshangpu-Early Naijiahe Period), and (3) the late extinction stage (Late Naijiahe Period). The evolution of Liupanshan Basin is closely related to that of Ordos Basin and it is further associated with tectonic transition of the northern North-South tectonic belt.

中文翻译：

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六盘山盆地下白垩统地层物源分析：古洋流指标，砾岩碎屑成分和锆石U-Pb年代学

六盘山盆地是北南北构造带的主要部分。六盘山盆地下白垩统地层记录了该地区的构造-沉积演化过程，对于了解六盘山盆地的原始沉积形态至关重要。在这项工作中，我们对白垩纪早期六盘山盆地的物源和构造沉积演化进行了研究。利用下白垩统三桥组和上商铺组的古古流向，砾石碎屑组成和碎屑锆石U-Pb同位素分析来确定物源。三桥组砾岩砾石碎屑组成（主要包括岩浆岩，变质岩和石灰岩）在不同地方表现出各种特征，揭示源区的不同岩石成分。三桥组和河上铺组的古流向表明，沉积物是从盆地边缘运到中心的。六盘山盆地西北部火石寨断面的两个样品的碎屑锆石产生了从420 Ma到500 Ma的主要单峰分布，表明其来源单一。综合以上分析，与祁连-秦岭造山带的岩浆记录相比，三桥组和和上铺组碎屑岩主要来自祁连-秦岭造山带的近端变质岩浆岩和古隆起的灰岩中。 。结合沉积特征，我们得出结论六盘山盆地经历了多阶段的演化历史：（1）裂谷扩张早期（三桥期），（2）中跨和depression陷中期（河上铺-奈家河早期）和（3）灭绝后期（奈家河后期）。六盘山盆地的演化与鄂尔多斯盆地的演化密切相关，并且与北南北构造带的构造过渡进一步相关。