大兴安岭富西里地区辉长岩类岩石学特征、成因类型及构造环境研究

Petrogenesis and Tectonic Implications of Gabbros in the Fuxili Area,the Great Xing'an Mountain: Petrology,Geochemistry and Geochronology Constraints

大兴安岭富西里地区出露有一套辉长岩类岩石,为区域上钛磁铁矿的含矿母岩。该套岩石的岩石学、地球化学特征表明,研究区辉长岩类岩石地球化学上系属于偏碱性,岩浆源区为富集地幔,而其产出的构造环境为拉张环境。这套辉长岩类岩石的形成时代为新元古代(789.8±2.9Ma、798±5Ma),与新元古代兴华渡口岩群和新元古代侵入岩(二长闪长岩、花岗闪长岩、二长花岗岩)紧密伴生。额尔古纳地块主要由兴华渡口岩群构成,根据本次工作成果(辉长岩类岩石为拉张环境产物),暗示着兴华渡口岩群的构造环境可能同样为一个拉张环境-裂谷或弧后盆地环境。

The exposed gabbros in the Fuxili area of Great Xing＇ an Range are regional ore-bearing rock of titanomagnetite. Petrology, geochemistry for the gabbros revealed that it belongs to subalkaline rock, magmatic soure is enriched mantle and tectonic setting is tensional setting. The froming age of gabbros is the Neoproterozoic （789.8 ± 2.9 Ma and 798±5 Ma ）, which is closely associated with the Neorproterozoic Xinghuadukou Group and intrusive rock （monzodiorite, granodiorite and monzogranite）. The Argun massif is mainly composed of the Xinghuadukou Group, which is possibly formed in tension- al setting--rift or back-arc basin setting, on the basis of results in this work.