On Geological Characteristics and Genesis of the Dawan Beryllium and Molybdenum Deposit in Xiapu County,Fujian Province;
福建霞浦大湾铍钼矿床地质特征及成因初探
The Ordovician Dawan Formation of Yichang has been studied for a long time,but the graptolite succession of the formation is still poorly known,particularly due to the rare occurrences of graptolites.
根据宜昌陈家河剖面大湾组的笔石标本,确立笔石序列自下而上为:Didymograptellus eobifidus带、Corymbograptus deflexus带和Azygograptus suecicus带(大湾组下段),Exigraptus clavus带和Undulogr aptusaustrodentatus带(大湾组上段)。
Based on systematic and statistical study on the brachiopods from the Dawan Formation at Chenjiahe, Yichang, western Hubei Province, the biodiversity change is discussed in terms of the graptolitic biozones.
在对宜昌陈家河大湾组(Arenig期)腕足动物化石进行逐层统计和详细研究的基础上,以笔石带为单位讨论腕足动物分类单元多样性的变化,发现该地区腕足动物属级分异度在Corymbograptellus deflexus带达到首次峰值,比上扬子区处于正常浅海底域地区(如贵州桐梓、沿河一带)的腕足动物宏演化趋势(在Didymograptelluseobifidus带达到首次峰值)晚了一个笔石带的时限,辐射主要缘于Sinorthis群落在本地区的出现和极度繁盛。
The Lower to Middle Ordovician Dawan Formation (Arenig) and its coeval rocks are generally striking southwest-northeast, and are belted in horizontal distribution meanwhile transitional between the two neighboring rock units.
下、中奥陶统大湾组及其同期地层的总体走向为南西—北东向,横向上呈带状分布,从近岸到远岸呈渐变过渡。
Discussion on Chemo-Stratigraphic Characteristics of Boundary Bed between the Top Part of the Ordovician and the Basal Part of the Silurian at Dawangou Section,Keping,Xinjiang;
新疆柯坪大湾沟奥陶系顶部-志留系底部化学地层特征讨论
The basal part of the Middle Member of the Kepingtage Formation at the Dawangou Section (Keping County) in the Tarim Basin of Xinjiang yields abundant graptolites, brachiopods, trilobites, and bivalves in its mudstone and dolostone.
新疆塔里木盆地西北缘柯坪大湾沟剖面柯坪塔格组中段底部的泥岩夹白云岩地层中发现有较丰富的笔石、腕足类、三叶虫、双壳类等化石,其中笔石有4属8种及2个比较种和1个未定种,可能属笔石Coronograptuscyphus带至Coronograptusgregarius带。