青海西金乌兰还东河中二叠世埃达克岩的发现及其意义

在西金乌兰-金沙江缝合带西段还东河发现了中二叠世埃达克岩,其岩石类型主要为闪长岩。还东河埃达克岩与Ⅰ类埃达克岩化学成分相近,可能是俯冲洋壳熔融形成的产物。还东河埃达克岩的大地构造位置相当于西金乌兰-金沙江缝合带西段西金乌兰段,进一步证明了西金乌兰大洋板片向南俯冲消减的重要事实。埃达克岩常与金、银、铜、钼等热液和斑岩矿床密切共生,西金乌兰-金沙江缝合带东段具有丰富的铜、金等矿产资源,这一发现对在该带西段寻找该类矿产提供了一定的理论依据。

The discovery and significance of the Middle Permian adakites along the Huandong River north of the Xijir Ulan Lake,Qinghai

The Middle Permian adakites were recognized during the geological surveys in 2000-2002 along the Huandong River in the western part of the Xijir Ulan-Jinshajiang suture zone in Qinghai. This kind of rocks is represented by diorites,and similar in chemical composition to the type I adakites,which maybe resulted from the melting of the subducted oceanic crust. Tectonically,the adakites in the study area are confined to the Xijir Ulan section of the Xijir Ulan-Jinshajiang suture zone,implying that the Xijir Ulan oceanic slab was once subducted southwards. The adakites are often closely associated with hydrothermal and porphyry ore deposits such as gold,silver,copper and molybdenum deposits. The copper and gold mineral resources also abound in the eastern part of the suture zone. The discovery may provide a theoretical basis for the prospecting and exploration of the above-mentioned mineral resources in the western part of the suture zone.