西准噶尔都伦河东岩体镁铁质微粒包体的发现及成因探讨

西准噶尔地区晚古生代岩浆活动强烈, 在达尔布特构造带形成带状展布的花岗岩带。近年来, 对该区域大岩基研究较多, 而对区域内小岩体的研究较为局限, 主要集中在包古图一带成矿斑岩上。都伦河东岩体位于西准噶尔扎依尔山阔依塔斯地区, 其寄主岩石主要为一套中粒石英闪长岩、中粗粒花岗闪长岩、中粗粒黑云母花岗闪长岩组合。于其中新发现丰富的镁铁质微粒包体, 通过对暗色包体的野外展布特征、岩石学等特征研究, 确定其为岩浆混合成因, 是高温的幔源基性岩浆和温度相对较低的壳源酸性岩浆混合作用的产物, 这一认识为探讨都伦河东岩体的成因及壳-幔岩浆的混合作用提供了重要的佐证, 对于西准噶尔地区花岗岩类的成因类型和多样性的研究也具有区域性意义。

Discovery and Origin of Mafic Microgranular Enclaves of the Dulunhe Magma Mixing Granite in West Junggar

As a result of intensive magmatic activity in Neopaleozoic, large amount of intrusive granites exposed along the Daerbute fault in the center of western Junggar. Many researches have been conducted with the batholites, few focused on the small granite intrusions which mainly distributed in porphyry mineralization belt of the Baogutu region. Dulunhe granite is located in Kuoyitasi area of Zhayi'er Mountain, and its host rock mainly consists of medium-grain quartz diorite, medium-coarse granodiorite and medium-coarse biotite granodiorite. Abundant mafic microgranular enclaves can be found in the host rocks.Field distribution and petrology features of mafic enclave suggest that the Dulunhe granite is resulted from mixing of hyperthermal mantle-derived basic magma and crustal acid magma of relatively lower temperature, which provides important evidence for the origin of Dulunhe granite and crust-mantle magma migmatization in the study area, and also has great regional significance for the studies of the genetic type and diversity of the granite in west Junggar.