中国吉林大拉子组的时代探讨

大拉子组是我国东北地区早白垩世的典型层位,但该组的具体地质年代一直存在不同的看法。根据最近发现的植物化石材料,通过对大拉子组被子植物优势属的地质分布以及与国内外被子植物群的对比研究,发现大拉子组与北美Potomac带B中部的被子植物群较为相似,结合孢粉、昆虫、叶肢介、介形虫及鱼化石等其他生物化石证据,认为吉林大拉子组的地质时代很可能为阿尔必中期或晚期。

DISCUSSION ON THE GEOLOGICAL AGE OF THE DALAZI FORMATION IN JILIN PROVINCE, CHINA

The Dalazi Formation, located in Jilin province, is regarded as a typical horizon of the Early Cretaceous in Northeast China. However, its age has been much debated. Based on the recently discovered fossil plants from the Dalazi Formation,their geological distribution of the dominant genera of angiosperms is studied. A comparison of the angiosperm flora from the Dalazi with those abroad or elsewhere in China, the results show that a close relationship might exist between the flora from Dalazi Formation and that of the Potomac Subzone II-B in North American. Associated with other palaeontological evidence from palynoflora, insects, conchostracans, ostracodes, fish fossils, it is concluded that the geological age of the Dalazi Formation is most likely of middle or late Albian.