Mesozoic intermediate-felsic magmatic rocks in the eastern North China Craton commonly show geochemical similarity to adakites. However, the lack of direct constraints from partial melting experiments at high pressures and temperatures fuels a debate over the origin of these rocks. In this work, we performed partial melting experiments at 1.5 ​GPa and 800–950 ​°C on amphibolite samples collected from the vicinity of the Mesozoic potassium-rich adakitic rocks in the Zhangjiakou area, northern margin of the North China Craton. The experimental melts range from granitic to granodioritic compositions, with SiO₂ ​= ​56.4–72.6 ​wt.%, Al₂O₃ ​= ​16.1–19.3 ​wt.%, FeO∗ ​= ​2.4–9.6 ​wt.%, MgO ​= ​0.3–2.0 ​wt.%, CaO ​= ​0.6–3.8 ​wt.%, Na₂O ​= ​4.7–5.3 ​wt.%, and K₂O ​= ​2.6–3.9 ​wt.%, which are in the ranges of the surrounding Mesozoic potassium-rich adakitic rocks, except for the higher Al₂O₃ contents and the data point at 1.5 ​GPa and 800 ​°C. Trace element compositions of the melts measured by LA-ICP-MS are rich in Sr (849–1067 ​ppm) and light rare earth elements (LREEs) and poor in Y (<10.4 ​ppm) and Yb (<0.88 ​ppm), and have high Sr/Y (102–221) and (La/Yb)_n (27–41) ratios and strongly fractionated rare earth element (REE) patterns, whereas no obvious negative Eu anomalies are observed. The geochemical characteristics show overall similarity to the Mesozoic potassium-rich adakitic rocks in the area, especially adakites with low Mg#, again except for the data point at 1.5 ​GPa and 800 ​°C. The results suggest that partial melting of amphibolite can produce potassium-rich adakitic rocks with low Mg# in the eastern North China Craton under the experimental conditions of 1.5 ​GPa and 850–950 ​°C. The experimental restites consist of hornblende (Hbl) ​+ ​plagioclase (Pl) ​+ ​garnet (Grt) ​± ​clinopyroxene (Cpx), a mineral assemblage significantly different from that of the nearby Hannuoba mafic granulite xenoliths which consist of Cpx ​+ ​orthopyroxene (Opx) ​+ ​Pl ​± ​Grt. Chemically, the experimental restites contain higher Al₂O₃ but lower MgO and CaO than the Hannuoba mafic granulite xenoliths. We therefore argue that the Hannuoba mafic granulite xenoliths cannot represent the direct products of partial melting of the experimental amphibolite.

华北克拉通东部的中生代中长统岩浆岩通常显示出与adakite的地球化学相似性。但是，在高温高压下进行部分熔融实验缺乏直接的约束条件，引发了对这些岩石起源的争论。在这项工作中，我们对从华北克拉通北缘张家口地区中生代富钾质埃迪克岩附近收集的闪石样品进行了1.5 GPa和800-950°C的部分熔融实验。实验熔体的范围从花岗石到花岗闪长岩，SiO ₂  = 56.4-72.6 wt。％，Al ₂ O ₃  = 16.1-19.3 wt。％，FeO ∗ = 2.4-9.6 wt。 ％，MgO = 0.3-2.0 wt。％，CaO = 0.6-3.8 wt。％，Na ₂O = 4.7-5.3 wt。％，K ₂ O = 2.6-3.9 wt。％，除了较高的Al ₂ O ₃之外，都在周围中生代富钾质adakitic岩石的范围内含量和数据点为1.5 GPa和800°C。通过LA-ICP-MS测量的熔体的痕量元素组成富含Sr（849-1067 ppm）和轻稀土元素（LREEs），而Y（<10.4 ppm）和Yb（<0.88 ppm）较差，并且具有较高的Sr / Y（102-221）和（La / Yb）_n（27-41）比率和强分馏稀土元素（REE）模式，而未观察到明显的负Eu异常。地球化学特征显示出与该地区中生代富钾质埃达克质岩石的总体相似性，特别是低Mg＃的陶粒岩，除了数据点为1.5 GPa和800°C之外。结果表明，在1.5 GPa和850-950°C的实验条件下，华北克拉通东部的闪石的部分熔融可以生产出Mg＃低的富钾Adakitic岩石。实验性的辉石由角闪石（Hbl）+斜长石（Pl）+石榴石（Grt）±斜向辉石（Cpx）组成，其矿物组成与附近的汉诺巴镁铁质粒状异种岩组成明显不同。 +邻苯二酚（Opx）+ Pl±Grt。化学上₂ O _3，但MgO和CaO低于Hannuoba镁铁质粒状异岩。因此，我们认为汉诺巴镁铁质粒状异种岩不能代表实验性闪石的部分熔融的直接产物。