首次对扬子区奥陶纪大湾组的三叶虫相作了初步分析。在详细研究了湖北宜昌大坪大湾组30种三叶虫的地层和岩相分布的基础上，划分出3个生态组合，即：Asaphid-Pseudocalymene组合,Asaphid-Raphiophorid组合和Trinucleid组合，它们依次指示由浅而深的浅外陆棚环境。研究表明这3个组合在大湾组的交替出现应与阿仑尼克期海平面变化密切相关。

Stratigraphical ranges of 30 trilobite species are recorded from the Ordovician Dawan Formation (Arenig) at Daping, Yichang, Hubei Province, China. Three trilobite associations are differentiated with respect to palaeobathymetrical and sedimentological gradients: the Asaphid Pseudocalymene Association, the Asaphid Raphiophorid Association and the Trinucleid Association. Stratigraphical occurrence of these associations within the formation reflects transgressive and regressive phases within the Arenig Series. This provides the first information on trilobite biofacies relationships across the Dawan Formation in the Yangtze Block.

Q915.811 Q915.72

英国自然环境调查委员会博士生奖学金资助，国家自然科学基金 (Nos.49772 0 87,49872 0 0 5 )，国家重点基础研究专题经费 (G2 0 0 0 0 7770 0 )资助