摘要
近十几年来 ,随着同位素地质年代学的发展 ,伊通火山群地区新生代地层断代问题的研究取得了突破性的进展 ,对重新厘定过去东北泛称下更新统“白土山组”地层的年代找到了突破口。通过火山岩年龄的测定、火山岩与“白土山组”接触关系及孢粉组合的研究 ,确认伊通火山岩群地区的“白土山组”的地质时代为新近纪中新世 ,与松辽平原中心的“白土山组”时代不同。
In the recent ten years, a great advances in the study of dating Cenozoic strata in the Yitong volcanic area, but the age of the “Baitushan Formation” which was generally thought to belong to early Pleistocene Epoch in whole Northeast China is still unsettled. The Cenozoic basalt and grainrock are widely distributed in the Yitong volcanic cluster area. The contact condition between the two strata is that the basalt invaded grainrock of the “Baitushan Formation”. In the past time, the two strata were thought to belong to early Pleistocene Epoch. Recently, we dated eight basalt samples of seven volcanoes in the Yitong volcanic cluster area by using K-Ar method. The date shows that the age of those volcanoes is 7-23Ma and should belong to Miocene Epoch. So the “Baitushan Formation” invaded by basalt is earlier than the basalt. At the same time, we also analyzed the sporepollen composition of the “Baitushan Formation” in the area, which shows the character of the Neogene plant community. So, we think that the age of the “Baitushan Formation” in some areas of Northeast China should belong to the Neogene Period.
出处
《地层学杂志》
CSCD
北大核心
2001年第4期279-282,共4页
Journal of Stratigraphy
基金
国家自然科学基金资助的课题 (编号 :No.494710 13)
中国科学院长春净月潭遥感站基金资助的课题 (编号 :910 0 3)。
