摘要
甘肃天水东岔镇一带出露的宽坪岩群位于北祁连—北秦岭—华北板块交界地带,呈残留体状分布于花岗岩之中,主体为一套低角闪岩相变质的片麻岩、片岩夹斜长角闪岩。利用西北大学大陆动力学重点实验室LA-ICP-MS(激光剥蚀等离子体质谱)方法,对其中的斜长角闪岩进行单颗粒锆石微区U-Pb同位素测定,获得1753±14Ma的上交点年龄,为古元古代晚期;并反映出415±2Ma～383±2Ma的变质年龄信息。结合前人研究成果,认为区域上宽坪岩群主体形成年龄为中元古代,而研究区的宽坪岩群形成于古元古代,受到加里东晚期和华力西早期构造—热事件的改造。推测研究区的宽坪岩群可能属于华北古老基底南缘的组成部分。
Kuanping Rock Group that lies in Dongcha area,Tianshui,Gansu Province,is located in the join place of the North Qilian orogenic belt,the North Qinling orogenic belt,and the North China plate.It shows some remaining bodis surrounding in granites,and is mainly composed of gneiss,schist,and a little of amphibolite.U-Pb isotope of zircons from amphibolite are determined by LA-ICP-MS in the key laboratory of continental dynamics of Northwest University,and yielded a zircon U-Pb upper-intercept age of 1753±14Ma a...
出处
《地质学报》
EI
CAS
CSCD
北大核心
2007年第1期79-87,共9页
Acta Geologica Sinica
基金
中国地质调查局国土资源大调查研究项目"西北地区重要成矿带基础地质综合研究"(编号1212010510416)资助成果
