中文摘要：

通过野外地质观测、岩石地球化学分析及高精度加速器质谱（AMS）14 C测年等工作,对大兴安岭中段莫克河地区新生代火山活动进行了详细研究。结果表明：莫克河地区新生代火山活动活跃,覆盖面积超过80km2,喷发方式为斯特朗博利型喷发。火山活动最早始于晚更新世,火山活动经历了4个火山喷发旋回,并在第一、二个火山旋回之间有短暂的间歇。火山岩为以低硅、高镁、高钾、高钛为主要特征的高钾钙碱性橄榄玄武岩。综合周边地区资料,研究区新生代火山岩是在拉张的构造环境下、以复活的深大断裂为通道产生的板内OIB型玄武岩,岩浆在上升过程中没有或很少发生壳源物质混染,也没有发生斜长石结晶分异,但有橄榄石、单斜辉石的分离结晶作用。

英文摘要：

Based on field geological survey,petrogeochemical analysis and 14C dating by high precision accelerator mass spectrometry,the Cenozoic volcanism in the Mock River region of central Daxing＇anling has been studied.It＇s proved that there happened active volcanisms in the Cenozoic period in Mock River region,which covered over 80 km2 area and erupted in the strombolian style.The earliest volcanism started in the Late Pleistocene period and experienced four eruption cycles.There was a short-term intermittent between the first and second eruption cycles.The volcanic rock resulted from the Cenozoic volcanism in the Mock River region belongs to the high K calc-alkaline olivine basalt,and characterized by low silicon（SiO2 content between 46.16% and 51.44%,the average is 48.66%）,high Mg（MgO content between 10.08% and 13.79%,the average is 10.36%）,high K（K2O content between 1.25% and 2.31%,the average is 1.53%）,high Ti（TiO2 content between 1.80% and 2.69%,the average is 2.30%）.Integrated data above with those in adjacent regions,some conclusions can be drawn as followings.Firstly,the Cenozoic volcanic rock in this area belongs to the OIB basalt derived from the reactivating deep fault under the extensional tectonic environment.Secondly,little or no crust-derived material was contaminated during the magma ascending.In addition,there happened fractional crystallization of olivine and clinopyroxene instead of plagioclase feldspar crystallization differentiation.