Quebecia is a unique Geon 15 to 13 composite arc belt in the central Grenville Province that preserves record of rifting and subsequent re‐amalgamation of part of the Laurentian margin. Key lithological components include: (a) c. 1.5 Ga metasedimentary sequences indicative of earlier rifting of the Laurentian margin; (b) remnants of 1.50–1.45 Ga peri‐Laurentian island arcs to the south built on rifted crustal slivers; (c) 1.45–1.42 Ga mafic dyke swarms to the northwest, linked to an asthenospheric window or back‐arc opening; (d) a major 1.43–1.37 Ga felsic plutonic belt marking the time of accretion to Laurentia; and (e) 1.38–1.35 Ga AMCG complexes suggesting slab‐breakoff and mafic underplating of the lower crust during arc accretion. Differences between Quebecia and continental arcs of the same age on both sides attest to lateral variations in subduction dynamics under Laurentia comparable to the modern‐day Andean system.

中文翻译：

---

东南劳伦山脉边缘的安第斯风格1.50–1.35 Ga弧动力学：魁北克的裂谷和重组

魁北克省是格伦维尔省中部独特的Geon 15至13复合弧形带，保留了裂谷和随后部分洛朗山脉边缘重新合并的记录。关键的岩性成分包括：（a）c。1.5 Ga沉积沉淀序列，表明Laurentian边缘较早裂谷；（b）以裂谷地壳条为基础，向南留下1.50–1.45 Ga圈周Laurentian岛弧；（c）1.45–1.42 Ga镁铁岩群向西北方向飞散，与软流圈窗口或后弧开口有关；（d）一条主要的1.43–1.37 Ga的长丝质前岩带，标志着Laurentia增生的时间；（e）1.38–1.35 Ga AMCG络合物表明弧积聚过程中下地壳的平板破裂和镁铁质底层。魁北克和两侧相同年龄的大陆弧之间的差异证明，在劳伦蒂亚时代，俯冲动力的横向变化与现代的安第斯山脉系统相当。