Paleomagnetic polarity reversals in Marinoan (ca. 600 Ma) glacial deposits of Australia: Implications for the duration of low-latitude glaciation in neoproterozoic time

Publication Type  Journal Article
Year of Publication  1999
Authors  Sohl, L. E.; Christie-Blick, N.; Kent, D. V.
Journal Title  Geological Society of America Bulletin
Volume  111
Issue  8
Pages  1120-1139
Journal Date  Aug
ISBN Number  0016-7606
Accession Number  ISI:000081729800002
Key Words  adelaide fold belt; cambrian boundary problem; south-australia; amadeus basin; low paleolatitude; proterozoic stratigraphy; surface temperatures; acraman impact; rapitan group; west-africa

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 degrees, I = -14.7 degrees, alpha(95), = 12.7 degrees, paleolatitude = 7.5 degrees). The underlying preglacial Yaltipena Formation also carries low magnetic inclinations (mean D = 204.0 degrees, I = -16.4 degrees, alpha(95), = 11.0 degrees, paleolatitude = 8.4 degrees), 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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