Paleomagnetic Polarity Reversals in Marinoan (ca. 600 Ma) Glacial Deposits of Australia: Implications for the Duration of Low-Latitude Glaciation in Neoproterozoic Time

Sohl, Linda E.; Christie-Blick, Nicholas; Kent, Dennis V.

A paleomagnetic investigation of Marinoan glacial and preglacial deposits in Australia was conducted to reevaluate Australia's paleogeographic position at the time of glaciation (ca. 610–575 Ma). The paleomagnetic results from the Elatina Formation of the central Flinders Ranges yield the first positive regional-scale fold test (significant at the 99% level), as well as at least three magnetic polarity intervals. Stratigraphic discontinuities typical of glacial successions prevent the application of a magnetic polarity stratigraphy to regional correlation, but the positive fold test and multiple reversals confirm the previous low paleolatitude interpretation of these rocks (mean D = 214.9°, I = −14.7°, α95 = 12.7°, paleolatitude = 7.5°). The underlying preglacial Yaltipena Formation also carries low magnetic inclinations (mean D = 204.0°, I = −16.4°, α95 = 11.0°, paleolatitude = 8.4°), suggesting that Australia was located at low paleolatitude at the onset of glaciation. The number of magnetic polarity intervals present within the Elatina Formation and the Elatina's lithostratigraphic relationship to other Marinoan glacial deposits suggest that glaciation persisted at low latitudes in Australia for a minimum of several hundreds of thousands to millions of years.

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Geological Society of America Bulletin