Radiometric Dating of Ignimbrite from Inner Mongolia Provides no Indication of a Post-Middle Jurassic Age for the Daohugou Beds  

作　　者：GAO Ke-Qin REN Dong 

机构地区：[1]School of Earth and Space Sciences, Peking University, Beijing 100871 [2]College of Life Science, Capital Normal University, Beijing 100037

出　　处：《Acta Geologica Sinica(English Edition)》2006年第1期42-45,共4页地质学报（英文版）

基　　金：The research was supported by the National Natural Science Foundation of China （grant #40272006, 30430100, 30370184）;RFDP of the Chinese Ministry of Education, and RCQJ Project of Beijing Municipal Commission of Education. Thanks are given to Prof. R. C. Fox （University of Alberta） for reading and improving the manuscript.

摘　　要：Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of key fossils of the Jehol Biota. Compelling evidence revealed by more rigorous research involving regional biostratigraphy, radiometric dating, and paleontology supports the Middle Jurassic age of the fossil beds. Despite the awesome evidence for the Middle Jurassic age of the Daohugou beds, the age dispute has been resurrected recently by invoking an overturned stratigraphic sequence. A careful review of the data, however, found no evidence that this sequence has been overturned. In addition, many of the assumptions, on which the conjecture of the fossil beds being post- Middle Jurassic is imprudently based, are self-contradictory or otherwise misleading. Thus, the post- Middle Jurassic age of the Daohugou beds as an unfounded conclusion can readily be dismissed.Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of key fossils of the Jehol Biota. Compelling evidence revealed by more rigorous research involving regional biostratigraphy, radiometric dating, and paleontology supports the Middle Jurassic age of the fossil beds. Despite the awesome evidence for the Middle Jurassic age of the Daohugou beds, the age dispute has been resurrected recently by invoking an overturned stratigraphic sequence. A careful review of the data, however, found no evidence that this sequence has been overturned. In addition, many of the assumptions, on which the conjecture of the fossil beds being post- Middle Jurassic is imprudently based, are self-contradictory or otherwise misleading. Thus, the post- Middle Jurassic age of the Daohugou beds as an unfounded conclusion can readily be dismissed.

关 键 词：Daohugou beds Inner Mongolia Middle Jurassic age dispute radlometric dating 

分 类 号：P534.52[天文地球—古生物学与地层学]