地质与资源2019，Vol.28Issue(3)：223-230,253,9.
大兴安岭北部雄关地区倭勒根岩群大网子岩组火山岩地球化学特征
GEOCHEMISTRY OF THE VOLCANIC ROCKS OF DAWANGZI ROCK FORMATION IN NORTHERN DAXINGANLING MOUNTAINS
摘要
Abstract
The Dawangzi rock formation of Wolegen rock group in Xiongguan area,northern Daxinganling Mountains, is composed of mainly meta﹣clastic rocks with metarhyolite and meta﹣trachyandesite. The zircon U﹣Pb dating of the trachyandesite by ICP﹣MS yields the 206Pb/238U age of 443.8﹣783.8 Ma,with the zircon U﹣Pb concordia age of 463.7 ± 2.1 Ma,and the weighted mean age of 463.6 ± 6.4 Ma (n＝10,MSWD ＝ 0.073). The tested zircons show developed oscillation rings,with the Th/U ratio generally ranging from 0.42 to 1.76,indicating a magmatic origin. This age represents the forming age of the trachyandesite,which is believed to be formed in Middle Ordovician,consistent with the formation time of regional Dawangzi rock formation (Cambrian﹣Early Silurian). The trachyandesite,belonging to alkali﹣calcic quasi﹣aluminous rocks,is characterized by unobvious Eu anomaly,depletion of HFSEs and enrichment of LILEs. The rocks have the features of crust﹣mantle mixed source,which was formed in the continental margin environment and related to the subduction of Paleo﹣Asian Ocean crust.关键词
锆石U﹣Pb年龄/地球化学特征/大网子岩组/大兴安岭北部Key words
zircon U﹣Pb age/geochemical characteristics/Dawangzi rock formation/northern Daxinganling Mountains分类
天文与地球科学引用本文复制引用
姜迎久,舒广龙,胥嘉,冯德胜,王春光..大兴安岭北部雄关地区倭勒根岩群大网子岩组火山岩地球化学特征[J].地质与资源,2019,28(3):223-230,253,9.基金项目
黑龙江省财政拨款"黑龙江省呼中区幅、大白山幅1:5万区域地质矿产调查"(编号:HLJKD2014-18). （编号:HLJKD2014-18）
