To better understand the origin and tectonic evolution of the Paleoproterozoic Jiao-Liao-Ji belt, North China craton, which have long been debated, we have conducted whole-rock geochemical and zircon U-Pb and Hf isotope analyses on Paleoproterozoic monzo(syeno)granitic gneisses and metamafic rocks from eastern Liaoning Province. The results indicate that these monzo(syeno)granitic gneisses and metamafic rocks formed concurrently at ca. 2.2–2.1 Ga. The monzo(syeno)granitic gneisses show geochemical features of A-type granites and were derived from dehydration melting of Archean tonalite-trondhjemite-granodiorite (TTG) with minor involvement of coeval mantle-derived magma in an extensional setting. The metamafic rocks are geochemically similar to mid-ocean-ridge basalt; they were generated by partial melting of isotope-depleted asthenospheric mantle in an intracontinental extensional setting and experienced crustal and continental lithospheric mantle contamination and fractional crystallization. Based on this study and published geological evidence, we propose the following tectonic model for the origin and geodynamic evolution of the Jiao-Liao-Ji belt: (1) Generation of high-density eclogitized lower crust accompanied by formation of voluminous Archean TTGs in the Eastern block; (2) intracontinental extension driven by upwelling of an asthenospheric hotspot along the Jiao-Liao-Ji belt in period of 2.20–2.0 Ga; (3) convergent orogenic processes between the Longgang block and Nangrim block governed by gravity-driven subduction of high-density eclogitized lower crust at ca. 1.95–1.85 Ga; and (4) postorogenic extension caused by delamination of the orogenic root and subsequent hot asthenospheric upwelling. This tectonic model can well explain the origin and geodynamic evolution of the Paleoproterozoic Jiao-Liao-Ji belt.

中文翻译：

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华北克拉通古元古代胶-辽-冀带陆内伸展与地球动力学演化: 辽宁东部同时期A型花岗岩和基性岩浆作用的洞察

为更好地了解争论已久的华北克拉通古元古代胶辽冀带的成因和构造演化，我们对古元古代monzo(syeno)进行了全岩地球化学和锆石U-Pb、Hf同位素分析辽东花岗片麻岩和变镁铁质岩. 结果表明，这些monzo（syeno）花岗片麻岩和变质岩同时形成于约。2.2-2.1 Ga. monzo(syeno)花岗片麻岩显示出A型花岗岩的地球化学特征，来源于太古代闪长岩-长闪长岩-花岗闪长岩(TTG)的脱水熔融，在伸展环境中少量参与了同时代地幔衍生的岩浆。变质岩在地球化学上类似于洋中脊玄武岩；它们是由大陆内伸展环境中同位素耗尽的软流圈地幔部分熔融产生的，并经历了地壳和大陆岩石圈地幔污染和分步结晶。基于这项研究和已发表的地质证据，我们提出了以下胶辽冀带起源和地球动力学演化的构造模型：（1）高密度榴辉岩化下地壳的生成伴随着大量太古宙 TTG 的形成。东区；(2) 2.20~2.0 Ga时期胶辽吉带软流圈热点上升流驱动的陆内伸展；(3) 龙岗地块和南格里姆地块之间的汇聚造山过程，受重力驱动下地壳高密度榴辉岩化下地壳俯冲作用控制。1.95–1.85 Ga；(4) 造山根的分层和随后的热软流圈上升流引起的造山后扩张。该构造模型可以很好地解释古元古代胶辽冀带的成因和地球动力学演化。