Middle Ordovician (Darriwilian) conodonts from allochthonous limestones in the Oakdale Formation of central New South Wales
Middle Ordovician (Darriwilian) conodonts from allochthonous limestones in the Oakdale Formation of central New South Wales
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新南威尔士州中部奥克代尔地层外来石灰岩中的中奥陶世（达里维尔）牙形刺
DOI：
10.1080/03115510408619276
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
I. Percival
中科院分区：
文献类型：
--
作者：
Y. Zhen;I. Percival
本文报道了中奥陶世晚期的牙形刺20种，其中包括两个新变型：Erraticodon bellevuensis sp. nov.和Ansella？haustra sp. nov.，的描述和说明，从异地石灰岩块在奥克代尔形成的贝尔河谷，西北部的Paroistodus horridus，Histiodella kristinae和Appalachignathus delicalulus的动物群的共同出现表明，石灰岩最初沉积在晚Darriwilian（最有可能早中期Da 3）的时间，提供了最大的年龄限制其列入奥克代尔形成。这种牙形石动物群与（1）瓦林加石灰岩段下方费尔布里奇火山内的异地石灰岩碎屑和（2）阿达米纳比群盆地浊积岩相中的同期深水硅质岩之间存在一些明显的动物群相似之处。后者的相似性表明，在下坡位移进入奥克代尔组之前，石灰岩的原始沉积环境是在不稳定的外陆架边缘，而不是在浅水深度。
Twenty species of late Middle Ordovician conodonts including two new forms, Erraticodon bellevuensis sp. nov. and Ansella? haustra sp. nov., are described and illustrated from allochthonous limestone blocks in the Oakdale Formation of the Bell River Valley, N.S.W. The co-occurrence of Paroistodus horridus, Histiodella kristinae and Appalachignathus delicalulus in the fauna suggests the limestone was originally deposited in late Darriwilian (most likely early-mid Da3) time, providing a maximum age constraint on its inclusion in the Oakdale Formation. Some faunal similarities are apparent between this conodont fauna and that from (1) allochthonous limestone clasts within the Fairbridge Volcanics below the Wahringa Limestone Member and (2) contemporaneous deep-water cherts in basinal turbidite facies of the Adaminaby Group. The latter similarity suggests that prior to downslope displacement into the Oakdale Formation, the original depositional environment of the limestone was on an unstable outer shelf edge rather than in shallow water depths.