漠河盆地额木尔河群锆石U-Pb年龄及地质意义  

LA-ICP-MS U-Pb GEOCHRONOLOGY OF THE SEDIMENTARY ROCK AND VOLCANO ROCK ZIRCONS FROM THE EMOERHE GROUP IN THE MOHE BASIN AND ITS GEOLOGICAL SIGNIFICANCE

作　　者：赵立国 杨晓平 赵省民[2] 刘渊 张文龙 

机构地区：[1]黑龙江省地质调查研究总院齐齐哈尔分院,哈尔滨150036 [2]中国地质调查局油气资源调查中心,北京100029

出　　处：《地质力学学报》2014年第3期285-291,共7页Journal of Geomechanics

基　　金：中国地质调查局天然气水合物资源勘查与试采专项"东北冻土区天然气水合物资源勘查项目"(GZHL20120302)

摘　　要：大兴安岭北部漠河盆地额木尔河群自下而上由绣峰组、二十二站组、漠河组和开库康组组成,目前对额木尔河群形成时代还存在不同的认识。绣峰组含砾粗砂岩及二十二站组碎屑岩中流纹质凝灰岩夹层激光探针（LA-ICP-MS）锆石U-Pb测年结果表明,绣峰组含砾粗砂岩中的碎屑锆石U-Pb年龄变化于距今2195~163 Ma之间,暗示了源区有古元古代基底存在,这一年龄数据与盆地周缘分布的基底岩石时代相吻合。碎屑锆石中5个最年轻锆石的206Pb/238U年龄加权平均值为167±2 Ma,反映绣峰组沉积下限为中侏罗世中期;二十二站组流纹质凝灰岩岩浆锆石206Pb/238U年龄加权平均值为148±2 Ma,由此限定二十二站组形成时代为晚侏罗世晚期。锆石U-Pb年龄数据反映额木尔河群沉积时间为中—晚侏罗世,这一认识对恢复漠河盆地形成演化历史及油气资源勘查提供了新的证据。Emoerhe Group in the Mohe Basin of northwestern Daxing＇ anling consists of Xiufeng Formation, Ershierzhan Formation, and Kaikukang Formation. Currently on Emoerhe Group＇s Formation age is still controversial. Study on the Zircon LA-ICP-MS U-Pb age of the Xiufeng Formation pebbly coarse sandstone sedimentary rock and interlayer of Rhyolitic tuff in Ershierzhan Formation clastic rock show that Xiufeng pebbly sandstone coarse detrital zircon U-Pb ages varied from 2195 Ma to 163 Ma. This alludes that the source region is Proterozoic-Middle Jurassic basement. The aging data of the basement rocks and the periphery of the basin are coincide. Detrital zircons in the five youngest zircon ^206ph/^238U weighted mean age of （167 ±2） Ma. It reflects the sedimentary basin limit of early Late Jurassic. Ershierzhan Rhyolitic tuff magmatic zircons ^206pb/^238U weighted mean age of （148 ± 2） Ma which suggests the basin sedimentation occurred in the Late Jurassic Period. Zircon U-Pb age data reflect Emoerhe Group deposition time was in Late Jurassic. It provides new evidences to restore the Mohe Basin evolution and resources exploration.

关 键 词：漠河盆地 额木尔河群 锆石U-PB年龄 

分 类 号：P597[天文地球—地球化学]