Paleoproterozoic and Archean rocks in the poorly exposed Yangtze Craton provide a unique proxy for understanding early cratonic evolution. In this study, we report the newly discovered Paleoproterozoic granitoids, mafic dikes, and metasedimentary rocks in the Susong area near the northern margin of the Yangtze Craton. The zircon U–Pb analysis results of the Luohanjian granite (hereinafter referred to as LHJ-granite) and mafic dikes yielded ²⁰⁷Pb/²⁰⁶Pb ages of 2020–2002 Ma and 1837 ± 21 Ma, respectively. Metasedimentary strata that were intruded by the mafic dikes yielded detrital zircon ²⁰⁷Pb/²⁰⁶Pb ages of 2.55–2.32 Ga and 2.15–1.93 Ga, suggesting a depositional age of ∼ 1.90–1.85 Ga for the metasedimentary rock. The whole-rock ε_Nd(t) and zircon ε_Hf(t) values of the LHJ-granite were negative and ranged from − 10.4 to − 9.4 and − 11.4 to − 9.0, with corresponding T_DM2 model ages of 3.3–3.2 Ga and ∼ 3.1 Ga, respectively. This implies that the granitic magma originated from the reworking of ancient pre-existing crustal components. The granitoids were weakly peraluminous (A/CNK = 1.00–1.18) with high SiO₂ concentrations of 71.98–76.00 wt%, LREE enrichment, high (La/Yb)_N values of 26.55–100.49, and moderately negative Eu anomalies, characterized by the enrichment of Rb, Ba, Th, U, and Nd, and the relative depletion of Nb, Ta, Sr, P, and Ti. These granite samples exhibited a negative correlation between SiO₂ and P₂O₅ and low Rb/Ba (0.15–0.33) and Rb/Sr (0.30–1.55) ratios. All these features indicate that the LHJ-granite is most likely belongs to I-type granite, which may have formed via the reworking of the TTG gneiss during subduction–collisional events. In combination with the mafic dikes and metasedimentary strata, our study proposes a mid–late Paleoproterozoic geological transition from a compressional to an extensional setting, indicating a tectonic shift from a collision orogeny (2.0 Ga) to a post-collision extensional environment (1.84 Ga) in the Susong region.

暴露不足的扬子克拉通中的古元古代和太古代岩石为了解早期克拉通演化提供了独特的代表。在这项研究中，我们报告了扬子克拉通北缘苏松地区新发现的古元古代花岗岩、基性岩脉和变质沉积岩。罗汉尖花岗岩（以下简称LHJ-花岗岩）和镁铁质岩脉的锆石U-Pb分析结果分别为²⁰⁷ Pb/ ²⁰⁶ Pb年龄为2020-2002 Ma和1837±21 Ma。被基性岩脉侵入的变质沉积地层产生碎屑锆石²⁰⁷ Pb/ ²⁰⁶ Pb 年龄为 2.55-2.32 Ga 和 2.15-1.93 Ga，表明变沉积岩的沉积年龄为 1.90-1.85 Ga。全岩εLHJ 花岗岩的_Nd (t) 和锆石 ε _Hf (t) 值为负，范围为 - 10.4 至 - 9.4 和 - 11.4 至 - 9.0，相应的 T _DM2模型年龄为 3.3-3.2 Ga 和 ~ 3.1 Ga，分别。这意味着花岗岩岩浆起源于古代预先存在的地壳成分的再加工。花岗岩为弱过铝质 (A/CNK = 1.00–1.18)，SiO ₂浓度高，71.98–76.00 wt%，LREE 富集，高 (La/Yb) _N值 26.55–100.49，中度负 Eu 异常，特征为Rb、Ba、Th、U 和 Nd 的富集，以及 Nb、Ta、Sr、P 和 Ti 的相对消耗。这些花岗岩样品在 SiO ₂和 P之间表现出负相关₂ O ₅和低 Rb/Ba (0.15–0.33) 和 Rb/Sr (0.30–1.55) 比率。所有这些特征表明 LHJ-花岗岩很可能属于 I 型花岗岩，它可能是通过俯冲碰撞事件期间 TTG 片麻岩的再加工形成的。结合基性岩脉和变沉积地层，我们的研究提出了从挤压环境到拉伸环境的中晚期古元古代地质转变，表明构造从碰撞造山运动（2.0 Ga）到碰撞后拉伸环境（1.84 Ga） ）在宿松地区。