Abstract Resolving magmatic tempos of multiple scales along convergent plate margins presents a pivotal task in any regional tectonic and supercontinental reconstructions, as is of paramount importance for the northern North China Craton (NCC) that converged with the Central Asian Orogenic belt (CAOB) during the Paleozoic to early Mesozoic. This study applies the integrated zircon U Pb dating and geochemical tracing to late Permian to late Triassic intrusive flare-up in northwestern Liaoning, with three episodes of granitic suites deciphered. Their contrasting elemental and isotopic features called for three distinct crustal end-members involved in their formation: ancient amphibolitic protolith, Paleozoic-accreted mafic meta-igneous ingredients and relaminated juvenile intermediate arc plutons. Sequential crustal anatexis of these multiply juxtaposed protoliths in a felsic hot zone tends to yield successive parental magmas for forming three granite suites. While the late Permian (260–250 Ma) granites, with their felsic adakitic affinity and variably evolved isotopic compositions (87Sr/86Sri = 0.70637 to 0.70659, eNd(t) = −16.7 to −10.2, zircon eHf(t) = −18.1 to +1.1), are consistent with partial melts of major ancient crustal materials and minor newly-underplated mafic ingredients, the middle Triassic (242–240 Ma) granites show a more juvenile isotope signature (eNd(t) = −11.8 to −4.7, zircon eHf(t) = −14.7 to +4.1) and attest to distinctively higher input from newly-underplated mafic lower crust in their formation. By contrast, the late Triassic (227–223 Ma) granites exhibit an A-type magmatic affinity. Their radiogenic whole-rock Nd (eNd(t) = −3.7 to +1.1) and zircon Hf (eHf(t) = +0.7 to +12.0) isotopic values suggest magma derivation from high-temperature fusion of dominantly relaminated juvenile charnockitic protolith. What follows is one phase of shoshonitic mafic dykes that fingerprint a slab-melt metasomatized asthenosphere source with depleted isotopic compositions (87Sr/86Sri = 0.70374 to 0.70388, eNd(t) = +3.5 to +4.1). Synthesizing these events with the previously recognized ones leads to a first-order duration of ca. 260–218 Ma for the flare-up and its further differentiation into three secondary pulses including ca. 260–250 Ma appinite and granite, ca. 242–238 Ma ferroan granites and ca. 227–218 Ma A-type granites and mafic dykes. While such primary duration is typical of post- collisional/orogenic magmatic tempos of convergent continental margins, three secondary pulses encapsulate successive geodynamic processes from crustal thickening through orogenic collapse to lithospheric dripping in the aftermath of the Paleo-Asian oceanic closure. Featuring a coupled scenario of lithospheric thinning and crustal growth, the northwestern Liaoning case of cratonic-edge destruction serves as a prelude but also a contrast to the late Mesozoic large-scale decratonization across the eastern NCC possibly due to oceanic subduction of the paleo-Pacific plate.

中文翻译：

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辽宁西北部华北克拉通晚二叠世至晚三叠世岩浆爆发沿克拉通边缘跟踪去克拉通化过程

摘要 解决沿会聚板块边缘的多尺度岩浆节奏是任何区域构造和超大陆重建的关键任务，这对于与中亚造山带 (CAOB) 汇合的华北克拉通 (NCC) 至关重要。古生代至早中生代。本研究将综合锆石 U Pb 定年和地球化学示踪应用于辽宁西北部晚二叠世至晚三叠世侵入性爆发，破译了三集花岗岩套。它们对比鲜明的元素和同位素特征需要三个不同的地壳端元参与它们的形成：古老的角闪质原岩、古生代吸积的镁铁质变火成岩成分和重新分层的幼年中间弧岩体。长英质热区中这些多重并列的原岩的连续地壳深熔倾向于产生连续的母岩浆，以形成三个花岗岩套件。而晚二叠世 (260–250 Ma) 花岗岩具有长英质埃达克质亲和力和不同演化的同位素组成 (87Sr/86Sri = 0.70637 至 0.70659, eNd(t) = -16.7 至 -10.2, 锆石 eHf(t) = -到 +1.1)，与主要古代地壳物质的部分熔融和次要的新底基镁铁质成分一致，中三叠世 (242-240 Ma) 花岗岩显示出更年轻的同位素特征 (eNd(t) = -11.8 到 -4.7 , 锆石 eHf(t) = -14.7 至 +4.1) 并证明在它们的形成中来自新镀底的镁铁质下地壳的明显更高的输入。相比之下，晚三叠世（227-223 Ma）花岗岩表现出 A 型岩浆亲和力。它们的放射成因全岩 Nd（eNd(t) = -3.7 至 +1.1）和锆石 Hf（eHf(t) = +0.7 至 +12.0）同位素值表明岩浆源自主要重新分层的幼年炭质原岩的高温聚变。接下来是一个阶段的钾镁铁质岩脉，其指纹是具有耗尽同位素组成的板片熔体交代软流圈源（87Sr/86Sri = 0.70374 至 0.70388，eNd(t) = +3.5 至 +4.1）。将这些事件与先前识别的事件合成会导致一阶持续时间约为 260-218 Ma 用于爆发及其进一步分化为三个次级脉冲，包括约 260-250 Ma appinite 和花岗岩，约。242-238 Ma 铁质花岗岩和约。227-218 Ma A 型花岗岩和镁铁质岩脉。虽然这种主要持续时间是会聚大陆边缘碰撞后/造山岩浆速度的典型特征，但三个次生脉冲包含了从地壳增厚到造山崩塌到古亚洲大洋闭合后岩石圈滴落的连续地球动力学过程。辽宁西北部克拉通边缘破坏事件具有岩石圈减薄和地壳生长的耦合情景，既是前奏，又与华北克拉通东部晚中生代大规模去克拉通化形成对比，这可能是由于古太平洋的海洋俯冲造成的盘子。