Facies-dependent delta C-13 variation from a Cryogenian platform margin, South Australia: Evidence for stratified Neoproterozoic oceans?
Jonathan A Giddings, Malcolm W Wallace
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY | ELSEVIER | Published : 2009
Analysis of a Cryogenian interglacial platform margin in the Adelaide Geosyncline reveals a strong carbonate δ13C-facies relationship. Detailed chronostratigraphic correlation between sections ranging from shallow platform facies to deep basinal facies indicates the presence of a carbon isotopic gradient of between 8 and 11‰ in time-equivalent strata. Shallow-water back-reef facies have δ13C values up to 8.2‰, while equivalent basinal sediments have δ13C values between - 3 and 0‰. Allochthonous blocks that have been transported from the platform margin into basinal environments retain their heavy δ13C values (4-9‰) and are surrounded by basinal calcareous shales with light δ13C values (ave. ..View full abstract
The authors wish to thank David McKirdy and Tony Prave for their detailed and constructive reviews of the manuscript. The manuscript also benefited from review by Sandra McLaren. We are also grateful to Doug and Margaret Sprigg, and the Gammon Ranges National Park rangers for their support in carrying out fieldwork in the northern Flinders Ranges. JAG also acknowledges the support of an Albert Shimmins Postgraduate Writing-Up Award.