Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published May 2010 | Supplemental Material
Journal Article Open

Geobiology of the late Paleoproterozoic Duck Creek Formation, Western Australia


The ca. 1.8 Ga Duck Creek Formation, Western Australia, preserves 1000 m of carbonates and minor iron formation that accumulated along a late Paleoproterozoic ocean margin. Two upward-deepening stratigraphic packages are preserved, each characterized by peritidal precipitates at the base and iron formation and carbonate turbidites in its upper part. Consistent with recent studies of Neoarchean basins, carbon isotope ratios of Duck Creek carbonates show no evidence for a strong isotopic depth gradient, but carbonate minerals in iron formations can be markedly depleted in ^(13)C. In contrast, oxygen isotopes covary strongly with depth; δ^(18)O values as positive as 2‰ VPDB in peritidal facies systematically decline to values of −6 to −16‰ in basinal rocks, reflecting, we posit, the timing of diagenetic closure. The Duck Creek Formation contains microfossils similar to those of the Gunflint Formation, Canada; they are restricted to early diagenetic cherts developed in basinal facies, strengthening the hypothesis that such fossils capture communities driven by iron metabolism. Indeed, X-ray diffraction data indicate that the Duck Creek basin was ferruginous throughout its history. The persistence of ferruginous waters and iron formation deposition in Western Australia for at least several tens of millions of years after the transition to sulfidic conditions in Laurentia suggests that the late Paleoproterozoic expansion of sulfidic subsurface waters was globally asynchronous.

Additional Information

© 2010 Elsevier. Received 25 August 2009; revised 12 February 2010; accepted 15 February 2010; available online 4 March 2010. We thank the Agouron Institute for funding, Henry Goodall and Caroline Minnear for logistical support, Sally Sweetapple for field assistance, G. Eischeid for mass spectrometry assistance, N. Tosca for XRD guidance, B. Croft for XRD support, R. Millikan and J. Creveling for thoughtful comments, and David Fike and one anonymous reviewer for constructive criticisms. JPW was supported in part by the NASA Astrobiology Institute.

Attached Files

Supplemental Material - Appendix_1.pdf

Supplemental Material - Appendix_2.pdf

Supplemental Material - Appendix_3.pdf


Files (457.4 kB)
Name Size Download all
221.0 kB Preview Download
168.4 kB Preview Download
68.0 kB Preview Download

Additional details

August 23, 2023
October 20, 2023