Abstract Paired metamorphism is the hallmark of asymmetric subduction at Phanerozoic convergent plate margins, yet spatially and temporally linked paired metamorphic belts have rarely been documented in the Archean rock record. Here, we investigate the Neoarchean Dengfeng Complex, a typical granite–greenstone belt in the southern part of the North China Craton (NCC). Using petrography, geochronology, and phase equilibrium constraints on rocks from different lithostructural units, we suggest the ca. 2.54–2.50-Ga Dengfeng Complex represents a remnant of a spatially and temporally linked Neoarchean paired metamorphic belt. In the western part of the complex, a garnet amphibolite from a dominantly metabasic unit (MBU) records near peak P–T conditions of 6.3–10 kbar and ∼675–750 °C, corresponding to a high thermobaric ratio (T/P) of ∼720–1200 °C/GPa. Tonalite–trondhjemite–granodiorite (TTG) gneisses preserve evidence for partial melting, also consistent with relatively high T/P (∼875–1400 °C/GPa). In the eastern part of the Dengfeng Complex, two garnet amphibolites and three garnet quartz–mica schists from a dominantly metasedimentary unit (MSU) record peak P–T conditions of >9.8 kbar and ∼525–655 °C, corresponding to intermediate thermobaric ratios of ∼425–600 °C/GPa. Zircon and titanite U–Pb dating, coupled with existing ages of post-kinematic intrusions, constrain the metamorphic age to ca. 2.52–2.50 Ga. The metamorphic P–T data indicate that the MSU was buried to >30 km then exhumed to the near-surface by the early Paleoproterozoic. Our metamorphic results, when combined with recent structural and geochemical data, suggest the Dengfeng Complex records Neoarchean paired metamorphism, in which the higher thermal gradients reflect the arc–forearc region and the lower thermal gradients correspond to the accretionary complex. Our data indicate that the southern NCC experienced accretionary-to-collisional orogenesis with intra-oceanic subduction, forearc accretion (ca. 2.54–2.50 Ga), and subsequent arc–continent collision (ca. 2.50–2.47 Ga). The recognition of paired metamorphism in the NCC is consistent with widespread subduction and the operation of a plate tectonic regime in the late Archean.

中文翻译：

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新太古代成对变质作用：华北克拉通增生-碰撞造山作用的记录

摘要 成对变质作用是显生宙会聚板块边缘不对称俯冲的标志，但在太古代岩石记录中很少记录到空间和时间上相关的成对变质带。在这里，我们调查了新太古代登封杂岩，这是华北克拉通 (NCC) 南部典型的花岗岩-绿岩带。使用来自不同岩性单元的岩石的岩石学、地质年代学和相平衡约束，我们建议约。2.54-2.50-Ga登封杂岩代表了新太古代成对变质带的空间和时间联系的残余。在复合体的西部，来自主要变基单元 (MBU) 的石榴石角闪石记录了接近 6.3-10 kbar 和 ~675-750 °C 的峰值 P-T 条件，对应于高温压比 (T/P) ∼720–1200 °C/GPa。闪长岩-长闪长岩-花岗闪长岩 (TTG) 片麻岩保留了部分熔融的证据，也与相对较高的 T/P (~875-1400 °C/GPa) 一致。在登封杂岩体东部，来自主要变沉积单元 (MSU) 的两个石榴石角闪岩和三个石榴石石英-云母片岩记录了 >9.8 kbar 和 ~525-655 °C 的峰值 P-T 条件，对应于中间温压比约 425–600 °C/GPa。锆石和钛铁矿 U-Pb 测年，加上后运动侵入的现有年龄，将变质年龄限制在大约 2.52-2.50 Ga。变质 P-T 数据表明 MSU 被埋藏到 30 公里以上，然后在古元古代早期挖掘到近地表。我们的变质结果，结合最近的构造和地球化学数据，表明登封杂岩记录了新太古代成对变质作用，其中较高的热梯度反映了弧前区，较低的热梯度对应于增生复合体。我们的数据表明，NCC 南部经历了洋内俯冲、弧前增生（约 2.54-2.50 Ga）和随后的弧-大陆碰撞（约 2.50-2.47 Ga）的增生到碰撞造山作用。对 NCC 中成对变质作用的认识与太古代晚期的广泛俯冲和板块构造体制的运行是一致的。以及随后的弧-大陆碰撞（约 2.50-2.47 Ga）。对 NCC 中成对变质作用的认识与太古代晚期的广泛俯冲和板块构造体制的运行是一致的。以及随后的弧-大陆碰撞（约 2.50-2.47 Ga）。对 NCC 中成对变质作用的认识与太古代晚期的广泛俯冲和板块构造体制的运行是一致的。