Archaeocyaths of the White Point Conglomerate, Kangaroo Island, South Australia

Abstract

The White Point Conglomerate at Cape d’Estaing, Kangaroo Island, South Australia contains a polymict suite of transported clasts up to boulder size, including archaeocyath-bearing limestone clasts. Reef boundstone and bioclast floatstone and rudstone textures are evident among the limestones. The formation is a constituent of the Kangaroo Island Group, exposed along the central northern coast of the island. A total of 32 species of archaeocyaths, one radiocyath and one acanthinocyathide are described from sampled clasts. New taxa are the ethmocyathid Ussuricyathellus bellidoi sp. nov. and the sajanocyathid Emucyathus elinorae gen. et sp. nov. The assemblage correlates with the post–Flinders Unconformity interval elswhere in the Stansbury Basin and in the Arrowie Basin to the north, and indicates a late Botoman age in terms of the Siberian Cambrian stage scale. A substantial proportion of species in common between the Cape d’Estaing assemblage and the Koolywurtie Limestone Member fauna on Yorke Peninsula confirm that the latter unit is the likely source for the archaeocyath-bearing limestone clasts in the White Point Conglomerate. In contrast, there are no species in common between the Cape d’Estaing assemblage and that of the upper Sellick Hill Formation and lower Fork Tree Limestone on Fleurieu Peninsula.

http://zoobank.org/urn:lsid:zoobank.org:pub:FC416BB7-F7CF-403E-8343-D98214726CE9

南澳大利亚袋鼠岛d’Estaing海角White Point砾岩包含大如巨石的搬运碎屑的复矿碎屑岩岩套, 包括含古杯类的石灰石碎屑。礁灰岩和生物碎屑浮石及砾状灰岩纹理在灰岩中显而易见。这样的岩组组成袋鼠岛群, 沿岛的中北部海岸出露。从采样碎屑中, 一共有32个古杯动物种, 一个辐杯种和一个刺杯种被描述。新分类群是ethmocyathid Ussuricyathellus bellidoi sp. nov.和sajanocyathid Emucyathus elinorae gen. et sp. nov。该组合与Stansbury 盆地其它地区的和往北Arrowie盆地的后弗林德斯不整合间隔相对比, 根据西伯利亚寒武纪阶的划分, 指示其年龄为Botoman阶晚期。D’Estaing海角组合和约克半岛Koolywurtie灰岩段动物群之间有相当比例的共同种, 这点证实, 后者可能是单位在White Point砾岩中含古杯石灰石碎屑的来源地。与此相反, 在d’Estaing海角组合和Fleurieu半岛上的Sellick Hill组上部及Fork Tree灰岩下部的组合之间不存在共同种。

Key words:

• archaeocyath
• Cambrian
• Stansbury Basin
• White Point Conglomerate
• South Australia
• taxonomy
• biostratigraphy

Acknowledgements

This paper is a publication of Spanish National Research Council (CSIC) project CGL2009–07073, funded by the Spanish Ministry of Science and Innovation. Jim Jago (University of South Australia, Adelaide) demonstrated the Cape d’Estaing locality to P.D. Kruse in September 2010; he and other members of the Buck Quarry excavation team assisted with sampling. The Department of Primary Industries and Resources, South Australia (now Department for Manufacturing, Innovation, Trade, Resources and Energy; DMITRE), Adelaide provided ongoing support by arrangement of Elinor Alexander, most notably by way of access to facilities in the departmental Core Library. She and Les Tucker of the same department were always ready and willing to provide practical help. Françoise Debrenne (formerly Muséum National d’Histoire Naturelle, Paris) discussed taxonomic matters and provided valuable photographic documentation of type specimens. Andrey Zhuravlev (Departamento de Ciencias de la Tierra, Universidad de Zaragoza and Geologicheskiy Institute RAN, Moscow) advised on Russian localities and formations and their ages. Carice Holland (DMITRE, Adelaide) drafted Figs 1–2.