This study examines the original nature, tectonic setting, and evolution of Paleoproterozoic metasedimentary rocks in the Laoling Group of northern Jiao–Liao–Ji Belt (JLJB), in the northeastern margin of the Eastern Block of the North China Craton (NCC), using new petrological, whole–rock geochemical, geochronological, and Lu–Hf isotope data. The youngest detrital zircons constrain the maximum deposition age of the metasedimentary rocks to 1.97 Ga, and two metamorphic zircon age peaks correspond to 1.91 and 1.84 Ga for their metamorphism. The protoliths of the metasedimentary rocks in the Laoling Group were medium- to fine-grained clastic sediments, dominated by shale, graywacke, and claystone, with a smaller amount of sandstone, derived from Paleoproterozoic granites and coeval acidic meta-volcanic rocks, with minor contributions from Mesoarchean–Neoarchean basement rocks and Paleoproterozoic meta-mafic rocks. The protoliths of the metasedimentary rocks in the Dalizi Formation of the Laoling Group were deposited in a convergent margin setting, and subduction along the northern JLJB likely ended before ca. 1.91 Ga when the Longgang and Nangrim blocks collided. The ε_Hf(t) values of ca. 2.14 Ga zircons mostly lie between the depletion mantle and the chondrite evolution line, coupled with extensive coeval magmatism, are consistent with the ca. 2.14 Ga significant continental crust growth in this region. An integrated study of petrology, geochemistry, metamorphic P–T paths, and tectonic evolution suggests that the JLJB experienced two metamorphic events at ca. 1.91 and 1.84 Ga.

本研究利用华北克拉通东地块东北缘胶辽冀带北部劳岭群古元古代变沉积岩的原始性质、构造环境和演化新的岩石学、全岩地球化学、地质年代学和 Lu-Hf 同位素数据。最年轻的碎屑锆石将变质沉积岩的最大沉积年龄限制在1.97 Ga，两个变质锆石年龄峰值分别对应于1.91和1.84 Ga的变质作用。在老岭组沉积岩的原岩是中到细粒度碎屑沉积物，由页岩，杂砂岩，和粘土岩为主，与砂岩量较小，从古元花岗岩和同时代酸性衍生元-火山岩，中太古代-新太古代基底岩和古元古代变基性岩的贡献较小。老岭群大里子组变质沉积岩的原岩沉积在会聚边缘环境中，沿金龙江北缘的俯冲很可能在约 10 年前结束。1.91 Ga 当龙岗和 Nangrim 块碰撞时。ca的ε _Hf ( t ) 值。2.14 Ga 锆石多位于耗竭地幔和球粒陨石演化线之间，加之同时期广泛的岩浆活动，与约. 2.14 Ga 本区大陆地壳生长显着。岩石学、地球化学、变质P-T的综合研究路径和构造演化表明，JLJB 在大约. 1.91 和 1.84 Ga。