关键词: 锆石U-Pb年龄, 晚古生代, 花岗岩, 后造山, 塔溪地区, 黑龙江

Abstract: Abstract:The granites in Taxi area, located in the east of the Xingmeng orogenic belt,are mainly composed of syengranite and monzogranite.The zircon UPb( LAICPMS) age analyses from the granites is from 295 to 285 Ma,suggesting that it is the production of Late Paleozoic.According to macroscropical evidences it shows that the studied granite is weakly peraluminous,with middle to high K and the high K calcalkaline series,and that the result of the samples are enriched in light rare earth elements and depleted in heavy rare earth elements with weakly to moderate pronounced Eu anomalies. Evidences of the trace elements show that it is enriched in Rb,La and depleted in Ba,Sr of the LILE and enriched in Ce,Zr,Hf,Th and depleted in Nb,Ta of the HFSE. It is indicated that granitic magma crust and mantle contamination had occurred, with the participation of more crust source material, displaying the characteristics of postorogenic I type granite. We concluded that the granites formed in extruded to stretch conversion postorogenic environment,and that it is the product of postorogenic evolution after the collision of Xingan Block and Songnen Block.

Key words: zircon UPb age, Late Paleozoic, granite, postcollision, Taxi area, Heilongjiang