地质与资源2013，Vol.22Issue(4)：264-272,9.
大兴安岭中段突泉盆地高Mg#火山岩激光全熔40Ar/39Ar测年与地球化学特征
LASER 40Ar/39Ar DATING AND GEOCHEMISTRY OF THE HIGH-Mg# VOLCANIC ROCKS FROM THE TUQUAN BASIN IN CENTRAL DAXINGANLING
摘要
Abstract
A detailed study is carried out on petrology,laser 40Ar/39Ar dating and geochemistry of the high-Mg# volcanic rocks from Tuquan Basin in Central Daxinganling region on the ground of their genesis,magmatic origin and geological implication.It is concluded that the volcanic rocks comprise a series of the acid-medium rocks (namely,andesite and dacite) with the age of 136.0 ±2.0 Ma by the method of laser 40Ar/39Ar dating,identical to early Early-Cretaceous.Geochemically,these rocks show a close affinity to adakitic rocks,with SiO2 ≥57.50％,high Al2O3 (≥ 16.66％),MgO＜3.31％,Mg#＞45,low Y (averagely 17.53×10-6,＜18×10-6) and Yb (averagely 1.84×10-6,＜1.90×10-6),high Sr (＞534×10-6)and Ba (789×10-6-925×10-6),Sr/Y=22.71-73.54,Y/Yb=8.32-11.32,enriched LREE,depleted HREE and without significant Eu anomaly (average Eu/Eu*=0.94).The features listed above imply that the original magma for the studied rocks is most likely resulted from partial melting of the thickened lower crust and in turn contaminated by the basaltic magma.Combined with the tectonic evolution characteristics in this region in Mesozoic,the volcanics from the Tuquan Basin should be derived from partial melting of the thickened lower crust as the result of the collision of Mongol-Okhotsk (Paleo-Pacific) orogenic belt.关键词
大兴安岭中段/突泉盆地/高Mg#火山岩/激光全熔40Ar/39Ar测年/埃达克质岩Key words
Central Daxinganling/ Tuquan Basin/ high-Mg# volcanic rock/ laser 40Ar/39Ar dating/ adakitic rock分类
天文与地球科学引用本文复制引用
李永飞,孙守亮,郜晓勇..大兴安岭中段突泉盆地高Mg#火山岩激光全熔40Ar/39Ar测年与地球化学特征[J].地质与资源,2013,22(4):264-272,9.基金项目
中国地质调查项目"东北地区晚古生代以来构造演化特征综合研究"(编号1212011121085)、"古亚洲洋构造体制与滨太平洋构造体制叠加转变综合调查和研究"(编号1212011085473)、"松辽外围中新生代盆地群油气基础地质调查"(编号1212010813070)资助. （编号1212011121085）
