Kendall, Brian and Creaser, Robert A. and Calver, Clive R. and Raub, Timothy D. and Evans, David A. D. (2009) Correlation of Sturtian diamictite successions in southern Australia and northwestern Tasmania by Re–Os black shale geochronology and the ambiguity of “Sturtian”-type diamictite–cap carbonate pairs as chronostratigraphic marker horizons. Precambrian Research, 172 (3-4). pp. 301-310. ISSN 0301-9268 http://resolver.caltech.edu/CaltechAUTHORS:20090908-083702059
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Recent geochronological studies have raised concerns regarding the accuracy of regional and global correlations of Neoproterozoic sedimentary successions using relative dating methods such as carbon isotope chemostratigraphy and glaciogenic diamictite–cap carbonate lithological and geochemical characteristics. Precise and accurate radio-isotopic age constraints for Neoproterozoic sedimentary rocks thus remain a high priority for establishing a reliable Neoproterozoic chronostratigraphy. Here, we present a new Re–Os age of 640.7 ± 4.7 Ma from black shales of the upper Black River Dolomite (Togari Group, northwestern Tasmania) that represents a minimum age for deposition of the immediately underlying, diamictite-bearing Julius River Member. The upper Black River Dolomite Re–Os age is statistically identical to a Re–Os age of 643.0 ± 2.4 Ma previously determined for the Sturtian post-glacial Tindelpina Shale Member (Umberatana Group, Adelaide Rift Complex, southern Australia). Consistent with previous lithostratigraphic and stromatolite biostratigraphic evidence, the Re–Os ages suggest broadly coeval deposition of the Julius River Member and Sturtian diamictites and overlying organic-rich marine shales. Consideration of the Neoproterozoic geochronological database suggests that “Sturtian”-type diamictite–cap carbonate pairs cannot be used as chronostratigraphic marker horizons for global correlation of the Neoproterozoic rock record.
|Additional Information:||Copyright © 2009 Elsevier. Received 27 October 2008; revised 14 May 2009; accepted 26 May 2009. Available online 8 June 2009. The manuscript benefited from insightful comments by David Selby and Tony Prave. This research was supported by a Natural Sciences and Engineering Research Council (NSERC) Discovery Grant to Creaser and an Alberta Ingenuity Fund Ph.D. Studentship to Kendall, a David and Lucile Packard Foundation Fellowship to Evans, and by NSF-EAR 0739105 (Raub). Calver publishes with the permission of the Director, Mineral Resources Tasmania. The Radiogenic Isotope Facility at the University of Alberta is supported in part by an NSERC Major Resources Support Grant. Jaime Hallowes and Gayle Hatchard are thanked for technical assistance.|
|Subject Keywords:||Neoproterozoic; Sturtian; Black shale; Re–Os; Glaciation; Australia; Tasmania|
|Official Citation:||Brian Kendall, Robert A. Creaser, Clive R. Calver, Timothy D. Raub, David A.D. Evans, Correlation of Sturtian diamictite successions in southern Australia and northwestern Tasmania by Re-Os black shale geochronology and the ambiguity of 'Sturtian'-type diamictite-cap carbonate pairs as chronostratigraphic marker horizons, Precambrian Research, Volume 172, Issues 3-4, August 2009, Pages 301-310, ISSN 0301-9268, DOI: 10.1016/j.precamres.2009.05.001. (http://www.sciencedirect.com/science/article/B6VBP-4WGF16J-1/2/31f22b0b39112e235ed8dad9ad78bd27)|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||George Porter|
|Deposited On:||07 Oct 2009 22:01|
|Last Modified:||26 Dec 2012 11:19|
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