Two Paleoproterozoic glacio-eustatic cycles in the Turee Creek Group, Western Australia

Abstract

Widespread glaciations in the period 2.42–2.22 Ga have led to the suggestion of a Paleoproterozoic snowball Earth, yet this hypothesis has been difficult to substantiate. Here, we report the discovery of two Paleoproterozoic glacio-eustatic cycles from a predominantly marine succession in Western Australia, where previously only one had been recorded. Sedimentary facies characteristics reveal that each cycle sharply commenced with a falling stage systems tract and terminated with a transgressive systems tract, consistent with drawdown and subsequent release of large volumes of seawater from, and into, waxing and waning ice sheets, respectively. This discovery provides support for the widespread nature of Paleoproterozoic glaciations and a major climatic change accompanying the rise in atmospheric oxygen.