The Hengshan Terrane (HST) is a typical Archean terrane in the central North China Craton (NCC) and features Neoarchean-early Paleoproterozoic granitoid rocks and associated supracrustal rocks. Five geological events are identified in the HST, including (1) ~2.71–2.67 Ga tonalites-trondhjemites-granodiorites (TTGs) and monzogranites, (2) ~2.54–2.48 Ga diorites, TTGs and volcanics, (3) ~2.44–2.43 Ga monzogranites, (4) ~2.14–2.04 Ga monzogranites and (5) ~1.92–1.84 Ga granulite- to high-grade amphibolite- facies metamorphism. The ~2.5 Ga diorites exhibit low SiO₂ concentrations (55.67–62.61 wt%), high MgO content of 1.39–4.89 wt% with Mg# values (45–62) and positive ɛHf(t₂) values of +3.2−+7.8, and the magma originated from a mantle source that had been metasomatized by dehydration fluids and melts from subduction-related sediments and slabs. The ~2.5 Ga TTGs are characterized by variable MgO contents (0.56–2.32 wt%) and Mg# values (44–67), (La/Yb)_N values (13.76–98.19) and positive ɛHf(t₂) values of +2.8 to +6.5, and derived from the partial melting of tholeiitic basalts with slightly enriched REE patterns, similar to those of back-arc basin basalts (BABBs). And these granitoid melts were contaminated by mantle materials. The ~2.4 Ga monzogranites show high SiO₂ (69.09–73.46 wt%) and K₂O (3.31–7.52 wt%) contents and low MgO (0.11–1.23 wt%) contents, and their parent magmas originated from the partial melting of metamorphic graywackes.

The mantle material that generated the dioritic magmas was enriched by the important metasomatic agent of sediment-derived melts and fluids prior to magmatism. These observations, in conjunction with the occurrence of widespread coeval calc-alkaline volcanic rocks in the adjacent Wutai region, suggest that a slab subduction was the most likely geodynamic regime leading to the late Neoarchean magmatism in the HST. In view of the BABB sources of the TTGs, a Neoarchean back-arc basin slab subduction model may be appropriate, which is supported by several Phanerozoic analogs. The partial melting P-T conditions of the ~2.5 Ga slab-derived TTG magmas are estimated to have been 1.5 ± 0.2 GPa and 823 ± 32 °C on the basis of thermodynamic and trace element simulations, indicating a geothermal gradient of ~17 ± 2 °C/km and a possible Neoarchean hot subduction process in the HST.

横山地体（HST）是华北克拉通（NCC）中部的典型太古宙地体，其特征是新太古代早期的古元古代花岗质岩石及相关的壳上岩石。在HST中确定了5个地质事件，包括（1）〜2.71-2.67 Ga孔雀石-长晶石-花岗岩-闪长闪长岩（TTGs）和辉长岩，（2）〜2.54-2.48 Ga钙长石，TTG和火山岩，（3）〜2.44-2.43 Ga辉长花岗岩，（4）〜2.14-2.04 Ga辉长花岗岩，和（5）〜1.92-1.84 Ga花岗岩-高级角闪岩相变质作用。〜2.5 Ga闪长岩显示出低的SiO ₂浓度（55.67-62.61 wt％），高的MgO含量1.39-4.89 wt％，Mg＃值（45-62）和ɛHf（t _2为正）值为+ 3.2− + 7.8，岩浆起源于地幔源，该地幔源已被脱水流体交代并与俯冲作用相关的沉积物和板块融化。〜2.5 Ga TTG的特征在于MgO含量可变（0.56-2.32 wt％）和Mg＃值（44-67），（La / Yb）_N值（13.76-98.19）和ɛHf（t ₂）正值+从2.8到+6.5，并且源自具有略微富集的REE模式的可塑玄武岩的部分融化，类似于弧后盆地玄武岩（BABB）。这些花岗岩熔体被地幔材料污染。〜2.4 Ga辉长花岗岩显示出较高的SiO ₂（69.09-73.46 wt％）和K ₂O（3.31-7.52 wt％）含量和低MgO（0.11-1.23 wt％）含量，其母浆来自变质灰泥的部分熔融。

形成岩浆岩浆的地幔物质在形成岩浆作用之前被沉积物衍生的熔体和流体的重要交代作用剂所富集。这些观察结果，再加上邻近的五台地区广泛分布的近代钙碱性火山岩的出现，表明板块俯冲是最可能导致HST新古宙岩浆作用的地球动力学区域。鉴于TTG的BABB来源，新太古宙弧后盆地平板俯冲模型可能是合适的，这由几个生代类似物支持。部分熔融PT 根据热力学和微量元素模拟，约2.5 Ga板坯TTG岩浆的条件估计为1.5±0.2 GPa和823±32°C，这表明〜17±2°C / km的地热梯度和HST中可能存在的新古构造热俯冲过程。