松潘-甘孜造山带义敦岛弧中段三叠纪火山-沉积盆地的演化

通过对三叠纪义敦岛弧中段83条剖面和沉积等厚线的综合分析研究，将其划分为义敦弧后前陆盆地、义敦火山弧、昌台-禾尼弧间盆地群、沙鲁里火山岩浆弧、雄龙西-金厂沟弧前盆地群5个次级的构造古地理单元。其中弧后盆地主要有上麻绒和义敦2个沉积中心，义敦火山弧可进一步细分出果德、根隆、郎格、哈逮4个次级火山穹隆，弧间盆地群有拿它盆地、曲登盆地、夏塞盆地、哈日盆地，沙鲁里火山岩浆弧可进一步细分为木合沟和口娘公玛2个次级火山穹隆，弧前盆地有雄龙西盆地、莫坝盆地、金厂沟盆地等8个次级火山-沉积盆地。认为义敦岛弧的演化主要受理塘缝合带演化的控制，也受金沙江缝合带演化的影响，总体上在三叠纪经历了夭折裂陷槽→不成熟岛弧→成熟岛弧→残余盆地的演化历程。

Evolution of Triassic volcanic-sedimentary basins in the central segment of the Yidun island arc of the Songpan-Garze orogenic belt,western Sichuan,China.

According to a comprehensive study of 83 stratigraphic sections and depositional isopachs, the central segment of the Triassic Yidun island arc is divided into five tectonic-paleogeographic units, i.e.： the Yidun back-arc foreland basin, Yidun volcanic arc, Changtai-Heni interarc basin swarm, Shaluli volcanic magma arc and Xionglongxi-Jinchanggou forearc basin swarm. Of these, the Yidun back basin mainly has the Shangmarong depocenter and Yidun depocenter; the Yidun volcanic arc may be subdivided into the Guode, Genlong, Langge and Hadai volcanic domes; the interarc basin swarm include the Nata, Qudeng, Xiasai and Hari basins; the Shaluli volcanic magma arc is subdivided into the Muhegou and Kounianggongma volcanic domes; and the Xionglongxi-Jinchanggou forearc basin swarm comprises eight volcanic-sedimentary subbasins such as the Xionglongxi, Moba and Jinchanggou basins. It is thought that the evolution of the Yidun island arc was mainly controlled by the evolution of the Litang suture zone and also by the Jinshajiang suture zone. Generally, four stages are proposed for the basin evolution of the Triassic Yidun island arc： a failed aulacogen, an immature island arc, a mature island arc and remnant basins.