Palaeomagnetism and the age of the Tumblagooda Sandstone, Western Australia

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Abstract
Whilst acknowledging the geological evidence for a Silurian age of the Tumblagooda Sandstone of Western Australia, this article draws attention to palaeomagnetic data which suggest a significantly older age. The pole position from the Tumblagooda Sandstone provides a strong constraint on the location of the Australian Palaeozoic apparent polar wander path (APWP), and by inference on that of the Gondwana APWP. Although the use of this pole as a key pole cannot be justified because the age of the Tumblagooda Sandstone is not reliably known, comparison of this pole with a Siluro‐Devonian pole from eastern Australia, and Ordovician to Silurian poles from Africa (in an appropriate pre‐breakup reference frame), suggests an age of Ordovician. Palaeontological evidence from large eurypterid tracks suggests a Silurian to Devonian age. While stratigraphic evidence is meagre, isotopic data have been used to support a post‐Early Silurian age. However the isotopic data are shown to be compatible with a significantly older age.