滇西北独龙江岩浆弧和丙中洛地块的划分与特征

Division and characteristics of Dulongjiang magmatic arc and Bingzhongluo block in northwestern Yunnan

为查明滇西北贡山地区大地构造单元的划分与特征,系统收集整理了不同比例尺的区域地质调查资料,得出4方面新认识:1该区大地构造单元划分为独龙江岩浆弧和丙中洛地块,二者分界为向东倾斜的高黎贡山逆冲推覆断裂;2独龙江岩浆弧属腾冲造山带,丙中洛地块属三江造山带,其间被中特提斯洋所分隔;3中特提斯洋于中侏罗世打开,晚侏罗世—早白垩世早期向西俯冲消减,早白垩世晚期—晚白垩世闭合;4班公错—东巧缝合带在该区已被向西逆冲推覆的高黎贡山岩群(Pt_1G.)所压覆。

To clarify the division and characteristics of Gongshan tectonic units in northwestern Yunnan,the authors collected and collated different scaled regional geological survey data,and then obtained four new understandings：①tectonic units are divided into Dulongjiang magmatic arc and Bingzhongluo block,and the demarcation between them is the inclined eastward Gaoligong Mountain thrusting nappe fault;②Dulongjiang magmatic arc belongs to Tengchong orogenic belt,while Bingzhongluo block belongs to the Three River orogenic belt,which are separated by Meso-Tethys;③the Meso-Tethys opened in Middle Jurassic,westward subducted in Late Jurassicearly Early Cretaceous,and closed in later Early Cretaceous and Late Cretaceous;④Bangongcuo-Dongqiao suture zone in the district has been covering by the Gaoligong Mountain rock group which westward thrust nappe.