The Indosinian Orogeny plays a significant role in tectonic background and magmatic evolution in Indochina and surrounding regions. Being a part product of the Indosinian magmatism in northwest Vietnam during late Permian–middle Triassic period, Muong Luan granitoid pluton dominantly consists of granodiorite, less diorite and granite. This pluton is located in the Song Ma suture and assigned to the Dien Bien complex. Geochemically, the Muong Luan granitoid rocks are characterized by a wide range of SiO₂ contents (59.9–75.1 wt%) and high K₂O contents. They display typical features of I‐type granites. The presence of hornblende and no muscovite and cordierite in the rocks further supports for I‐type character of granitoids. The emplacement age of the Muong Luan pluton obtained by LA–ICP–MS U–Pb zircon is at 242–235 Ma, corresponding to Indosinian time. Zircon ε_Hf values of –5.6 to –10.4, in combination with moderate Mg values of 34–45 suggested that the Muong Luan granitoid was derived from partial melting of mafic crustal source rocks, which are probably Paleoproterozoic in age as revealed by Hf model ages (T_DM2 = 1624–1923 Ma).

中文翻译：

---

越南西北部Muong Luan花岗岩类岩体的地球化学，锆石U–PB年龄和HF同位素及其成岩意义

印度支那造山运动在印度支那及其周边地区的构造背景和岩浆演化中起着重要作用。Muong Luan花岗岩类岩体是越南西北部二叠纪-中三叠纪时期印支期岩浆作用的一部分，主要由花岗闪长岩，较少的闪长岩和花岗岩组成。该子体位于Song Ma缝合线中，并分配给Dien Bien建筑群。地球化学方面，Muong Luan花岗岩岩石的特征是SiO ₂含量范围广（59.9-75.1 wt％）和高K ₂O含量。它们显示出I型花岗岩的典型特征。岩石中存在角闪石，没有白云母和堇青石，进一步支持了花岗岩的I型特征。通过LA–ICP–MS U–Pb锆石获得的Muong Luan岩体的进位年龄为242–235 Ma，与印度支那时间相对应。锆石的_εHf值介于–5.6至–10.4之间，中等Mg值介于34–45之间，表明Muong Luan花岗岩来源于镁铁质地壳源岩的部分熔融，这可能是由Hf模型年龄所揭示的古元古代（T _DM2 = 1624–1923 Ma）。