Abstract: Based on the studies of the outcrop of Eogene System on the northwest margin of Jianghan Basin,the following results have been obtained:establishment of Eogene paleomagnetic polar time table,Eogene paleolatitude at that area and a discovery of upper Cretaceous index fossil Talycyprideu chinensis in previous"Eogene System".In consideration of the discovery and paleomagnetic time table,the Tertiary basal boundary has been corrected by moving 45.3m upward.

摘要： 本文通过对江汉盆地西北缘下第三系剖面的研究,建立了下第三系地磁极性年代系统,得出了地层形成时期的古纬度;在前人所划下第三系中发现了典型的晚白垩世介形类Talicyprideachinensis,Cypria triangularia等,结合地磁极性年代,将第三系底界上移45.3m.

关键词: 江汉盆地, 早第三纪, 古地磁, 古地磁地层学, 生物地层学, 地层剖面, 地层划分