Fauna and biostratigraphy of the Cambrian (Series 2, Stage 4; Ordian) Tempe Formation (Pertaoorrta Group), Amadeus Basin, Northern Territory

Abstract

A new faunal assemblage is reported from the Tempe Formation (Cambrian Series 2, Stage 4; Ordian) retrieved from the Hermannsburg 41 drillcore, Amadeus Basin, central Australia. Two trilobite taxa, including one new species Gunnia fava sp. nov., four brachiopod taxa, including the age-diagnostic Karathele napuru (Kruse), Kostjubella djagoran (Kruse) and Micromitra nerranubawu Kruse, together with a bradoriid, helcionellids, hyoliths, echinoderms, chancelloriids, sponges and problematic tubes are described. The fauna has close links to those of the neighbouring Daly, Georgina and Wiso basins and suggests that the Tempe Formation correlates with the Australian Ordian stage (either the Redlichia forresti or Xystridura negrina assemblage zones). The Giles Creek Dolostone in the eastern Amadeus Basin, previously regarded as coeval with the Tempe Formation, has recently been reported to be of early Templetonian age in its type section. The described taxa from the Tempe Formation confirm that these two sedimentary units are not contemporaneous and that regional stratigraphic schemes should be amended.

本文报道了采自澳大利亚中部Amadeus盆地Hermannsburg41掘井岩芯Tempe组（寒武纪第2系，第4阶; Ordian）的一个新动物组合。本文描述了两个三叶虫类群（包括新种Gunnia fava sp. nov.）、四个腕足动物类群（包括年代标准分子Karathele napuru（Kruse）、Kostjubella djagoran（Kruse）和Micromitra nerranubawu Kruse，以及高肌虫、太阳女神螺、 软舌螺、棘皮动物、开腔海绵、海绵和有争议的虫管。该动物群与邻近的Daly、Georgina和Wiso盆地的动物群有密切关系，这说明Tempe组与澳大利亚Ordian阶（Redlichia forresti 组合带 或 Xystridura negrina 组合带）相对比。Amadeus盆地东部的Giles Creek白云岩以前曾被视为与Tempe组同时代，最近有报道认为其层型剖面是早Templetonian阶。Tempe组所描述的分类群证实，这两个沉积单元是不同期的，区域地层方案应该修改。

Key words:

• trilobites
• brachiopods
• shelly fossils
• East Gondwana
• Australia.

Acknowledgements

We are indebted to Geoscience Australia (GA), Canberra for access to the Hermannsburg 41 drillcore. We also wish to thank Dr John Laurie (GA) for organizing the extraction of the core from the GA core library and for fruitful discussion on the stratigraphy of the Amadeus and Georgina basins. Core sampling assistance was provided by David Mathieson (Macquarie University, Sydney) and Jamie Lankford (GA). Components of the acid residue were picked by Hayley Bell (Macquarie University, Sydney). We are also indebted to Dean Oliver for the original drafting of Figs 1–3. This work has been supported by grants from the Macquarie University Postgraduate Fund (to PMS) and the Australian Research Council Discovery Project #120104251 (to GAB and JRP). We are grateful to Peter D. Kruse, Stephen McLoughlin and one anonymous reviewer for their constructive reviews of the manuscript.