Abstract The Late Triassic saw a period of broad uplift, vigorous magmatism and supracrustal stretching in the northern North China block, but the driving mechanism has been uncertain. Previous investigations have mostly dealt with individual tectonic processes, such as petrogenesis of igneous complexes, extensional deformations, or basin development, and the proposed models were aimed to account for some specific processes. This study makes a holistic treatment of Late Triassic denudation, magmatism, and rift basins in an attempt to unravel the driver for these coeval tectonic processes. Late Triassic uplift is registered by a regional disconformity separating Jurassic from Lower–Middle Triassic or older units, and Upper Triassic oligomict conglomerates are suggestive of early-stage peneplanation. The extensive uplift of the northern North China block was also accompanied by the development of the Great Ordos basin in the southern North China block, which exhibits striking southward variation from alluvial/fluvial through deltaic to lacustrine depositional settings. Vigorous magmatism is typified by mantle-sourced alkaline and mafic complexes distributed in an east–west narrow belt. The development of metamorphic core complex and some isolated rift basins is clearly indicative of crustal extension. Spatial variation from coeval island-arc calc-alkaline to backarc bimodal magmatism in the Amurian superterrane hints at southward subduction of the Mongol-Okhotsk plate. All the geologic records point to the plausibility that these synchronous tectonic processes must have been genetically linked and were likely induced by southward subduction of the Mongol-Okhotsk plate. Here, we argue that the Mongol-Okhotsk plate subduction not only triggered arc and backarc magmatism in the Amurian superterrane, but also led to decompression melting and focused upwelling of the upper mantle ahead of the subducting slab beneath the northern North China block. The Late Triassic intraplate extensive uplift, magmatism, and extension in the northern North China block are accordingly interpreted as the signatures of the focused mantle upwelling.

中文翻译：

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华北地块晚三叠世隆升、岩浆作用与伸展：地表地幔特征

摘要 晚三叠世在华北地块北部经历了广泛的隆升、强烈的岩浆活动和上地壳伸展，但其驱动机制尚未明确。以前的研究主要涉及单个构造过程，例如火成岩复合体的岩石成因、伸展变形或盆地发育，并且提出的模型旨在解释某些特定过程。本研究对晚三叠世剥蚀作用、岩浆作用和裂谷盆地进行了整体处理，试图揭示这些同时期构造过程的驱动因素。晚三叠世隆起被区域不整合记录，将侏罗纪与下-中三叠纪或更古老的单元分开，上三叠世寡聚体砾岩暗示早期的冲积。华北地块北部的广泛隆升也伴随着华北地块南部的大鄂尔多斯盆地的发育，呈现出从冲积/河流到三角洲再到湖相沉积环境的显着南向变化。强烈的岩浆活动以分布在东西窄带中的幔源碱性和镁铁质杂岩体为代表。变质核杂岩体和一些孤立裂谷盆地的发育清楚地表明了地壳伸展。阿穆尔超级地体中从同期岛弧钙碱性到弧后双峰岩浆作用的空间变化暗示蒙古-鄂霍次克板块向南俯冲。所有的地质记录都表明，这些同步的构造过程在遗传上肯定是有联系的，并且很可能是由蒙古-鄂霍次克板块向南俯冲引起的。在这里，我们认为蒙古-鄂霍次克板块俯冲不仅引发了阿穆尔超级地体的弧形和弧后岩浆作用，而且还导致了华北地块下方俯冲板块之前的上地幔减压熔融和集中上涌。华北地块北部晚三叠世的板内广泛隆升、岩浆活动和伸展被相应地解释为集中地幔上涌的特征。但也导致了华北地块下方俯冲板片之前的上地幔减压熔融和集中上涌。华北地块北部晚三叠世的板内广泛隆升、岩浆活动和伸展被相应地解释为集中地幔上涌的特征。但也导致了华北地块下方俯冲板片之前的上地幔减压熔融和集中上涌。华北地块北部晚三叠世的板内广泛隆升、岩浆活动和伸展被相应地解释为集中地幔上涌的特征。