甘蒙北山地区小红山一带变质侵入岩体的时代厘定及其地质意义

在塔里木板块北缘甘蒙北山地区小红山一带赋存一套变质侵入岩体,测定锆石U-Pb年龄值2 656±146 M a,时代厘定为新太古代晚期-早元古代早期,岩浆成因类型属Ⅰ型,物质来源于下地幔和地壳经局部熔融而成,是吕梁期前造山基底发育阶段的产物。该套变质侵入岩体的时代厘定,对于塔里木板块结晶基底的深入研究及甘蒙北山早期构造岩浆演化具有重要意义。

Time of definition and geological meaning for metamorphic intrusive rock body in Xiaohongshan region,Beishan area of Gansu and Inner Mongolia

The metamorphic intrusive rock body have first been discovered in Xiaohongshan of Beishan region of Gansu and Inner Mongolia, the north margin of Tarim paleoplate.With the zircon U-Pb age 2 656±146 Ma,its geologic age should be the end of Late Archean-Early Proterozoic.Magmatic genesis belong to Ⅰ-type which formed from the mantle and the crust by fusioning partly in Lüliang Period when the pre-orogenic basements were developing.There is an important significance that the metamorphic intrusive rock body was discovered,with which to study on the crystalline basements of Tarim paleolate and the early evolution for magma and strucure in the region of Beishan of Gansu and Inner Mongolia.