佳疙瘩组变碎屑岩地球化学特征及古构造环境

GEOCHEMISTRY AND TECTONIC SETTING OF METAMORPHIC DETRITAL ROCK OF JIAGEDA GROUP

内蒙古额尔古纳地区佳疙瘩组变碎屑岩的主量元素以富集SiO2 、Al2 O3 、K2 O、Na2 O等为特征 ,微量元素以富含高场强不相容元素为特征。岩石的地球化学特征表明其原岩为一套陆源碎屑岩。沉积环境为被动大陆边缘。沉积盆地性质为被动大陆边缘拉张 (早期 )和弧后拉张 (后期 )两种深部背景下的拉张断陷盆地。而基性岩浆的侵入活动代表这一过程的持续和进一步发展。

The major elements of metamorphic detrital rock of Jiageda Group, E'erguna region of Inner Mongolia, are characterized by enrichment in SiO 2 , Al 2 O 3 , K 2 O and Na 2 O, and the trace elements are characterized by enrichment in HFSE. The geochemical characterizes of metamorphic detrital rock show their source rocks were terrigenous detrital rocks . The sediment environment was in the passive continental margin. The sedimentation basin was extention trough basin which was controlled by tension of early passive continental margin and later back arc. The basic rock intrusive activity implied continuation and development of the tension process.