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分别对采自黑龙江北部科洛、莲花山和青龙山三座年轻火山的玄武岩样品进行了K_Ar定年研究 .未处理的全岩样品表面年龄分别为 (0 .0 6± 0 .0 1) ,(0 .15± 0 .0 3) ,(0 .17± 0 .0 2 ) ,(2 1.10± 0 .13)和 (2 4 .4 6± 0 .10 )Ma .样品粉碎至 80～ 10 0筛目 ,在显微镜下挑出橄榄石晶粒后 ,得到的表面年龄分别是 (0 .0 3± 0 .0 1) ,(0 .0 6± 0 .0 1) ,(0 .0 7± 0 .0 3) ,(2 .31± 0 .0 2 )和 (1.50± 0 .2 1)Ma .挑出橄榄石晶粒的玄武岩样品表面年龄下降 (年轻 )了 50 %至 94 % .纯橄榄石的表面年龄为 (6 9.8± 0 .9)Ma .实验结果表明 ,中国东部大面积分布的晚新生代含橄榄石的玄武岩在做K_Ar定年时 ,不能简单的使用全岩样品 ,必须挑出橄榄石晶粒 ,否则将导致错误的定年结果 .已出版的未挑出橄榄石的玄武岩定年结果 ,以及由那些结果得出的推理和结论 ,均应重新审查
K_Ar dating of three young volcanic basalts collected from Korlo, Lianhuashan and Qinglongshan in the northern part of Heilongjiang were studied respectively.The surface ages of the unprocessed whole rock samples were (0 .06 ± 0. 01), ( 0 .15 ± 0 .0 3), (0 .17 ± 0 .0 2), (2 1.10 ± 0 .13) and (2 4 .4 ± 0 .10) Ma. The sample was pulverized to 80 ~ 100 Mesh mesh, after the olivine crystal grains were picked out under a microscope, the surface ages obtained were (0 .03 ± 0 .0 1), (0 .6 ± 0 .0 1), (0 .0 ± 0 .0 3), (2.31 ± 0 .0 2), and (1.50 ± 0 .2 1) Ma. The basaltic surface of the basaltic rocks from which olivine grains were picked out fell by as much as 50% to 94% (younger) The surface age of olivine is (6 9.8 ± 0. 9) Ma. The experimental results show that the late Cenozoic olivine-rich basalts in eastern China can not simply use whole-rock samples during K_Ar dating. Peridot grains will result in erroneous dating results Published published basaltic results of olivine-free basalts, as well as the inferences and conclusions derived from those results, should be re-examined