Coupled carbon isotopic and sedimentological records from the Permian system of eastern Australia reveal the response of atmospheric carbon dioxide to glacial growth and decay during the late Palaeozoic Ice Age

Abstract

Proxy geochemical records from high-latitude, ice-proximal deposits have the potential to provide key insights into past icehouse climates, but such records are rare. The Permian System of eastern Australia contains a rich record of environmental and climatic changes that occurred in areas proximal to glaciation during the acme and waning stages of the late Palaeozoic ice age. Within this succession, a wealth of fine-grained, organic matter-rich facies provides an opportunity to construct a bulk δ 13 C org record that records changes in atmospheric CO 2 through the Permian. Fluctuations in δ 13 C org track changes in climate determined independently on the basis of sedimentological criteria in the same strata. These patterns are also broadly consistent with multiple proxy records derived from palaeoequatorial sites. The results of this geochemical investigation 1) support recent studies using the high-latitude, ice-proximal, sedimentologic and stratigraphic record and palaeoequatorial geochemical proxies that document highly variable climatic conditions within the overall Permian icehouse-to-greenhouse transition, and 2) confirms that the sedimentary record of glaciation from eastern Australia reflects global changes in atmospheric CO 2 on several m.y.-order timescales.