大兴安岭北部拉布达林盆地中生代烃源岩的时代归属

摘要

拉布达林盆地发育中生界厚层泥岩,具有烃源岩特征的岩层主要发育于原划归上库力组一段的中部和下部.拉布达林至下库力公路边491 km处发育原上库力组一段中部剖面,对产自该剖面厚层泥页岩下部的凝灰岩采用LA-ICP-MS技术,进行了锆石U-Pb年龄测定,获得的年龄值为156.7±1.8 Ma(MSWD=2.0),指示其形成时代为晚侏罗世,将其划归满克头鄂博组.该研究结果不仅丰富了大兴安岭北部中生代年代地层学的年龄数据,同时为区域油气地质调查寻找火山岩覆盖区的烃源岩层提供基础资料.%The thick Mesozoic mudstones are well developed in the Labudalin Basin.The strata with characters of hydrocarbon source rock mainly occur in the middle and lower part of the 1st Member,Shangkuli Formation.A section of the 1st Member of Shangkuli Formation was surveyed at 491 km of the Labudalin-Xiakuli highway,in which tuff was found below thick muddy shale.LA-ICP-MS dating for the tuff sample yields an age of 156.7±1.8 Ma (MSWD =2.0),indicating that the source rocks were formed in Late Jurassic.Therefore it is assigned to Manketouebo Formation.This result adds a dating datum to the Mesozoic chronostratigraphic study in northern Daxinganling Mountains,and provides basic information for source rock strata searching in the volcanic rock-covered regions as well.