Paleoclimatology of the Neoproterozoic interglacial to Marinoan glacial succession (∼650--575 Ma), Central Flinders Ranges, South Australia

Neoproterozoic climate patterns are unusual with respect to any patterns observed in the Phanerozoic Eon, principally owing to the occurrence of at least two broad intervals of severe glaciation that appear to have produced continental-scale ice sheets, at sea level, in the tropics. Paleomagnetic data acquired for this study directly from the Marinoan (∼610–575 Ma) glacial deposits of the Central Flinders Ranges of South Australia have yielded the best evidence yet in support of the low-latitude glaciation scenario. The presence of magnetic polarity reversals, and a positive regional fold test (significant at the 99% level), strongly suggest that South Australia lay at 7.5° latitude (min. 1.0°, max. 14.5°), during the waning stages of glaciation. Additional data from the underlying pre-glacial strata also yield a low paleolatitude of 8.4° (min. 5.4° max. 12.0°), suggesting that South Australia remained at low paleolatitudes from the onset of glaciation. The multiple magnetic polarity reversals suggest that the waning stages of glaciation in Australia may have persisted for a minimum of several hundreds of thousands to millions of years.; Between glacial intervals in Australia, the interglacial climate of the equatorial region appears to reflect tropical to subtropical conditions; the shelf morphology, sedimentology and mineralogy of the mixed carbonate-siliciclastic rocks of the Central Flinders Ranges bear most of the characteristics of warm-water deposits. The relative abundance of high-Mg calcitic and aragonitic precursors in the interglacial rocks also suggest, however, that warm conditions did not prevail globally, leaving open the possibility that relict ice sheets may have persisted at high latitudes from Sturtian through Marinoan time.; An evaluation of the current hypotheses addressing the origins of low-latitude glaciation in the Neoproterozoic suggests that neither is sufficient to address the problem, once the glacial events are examined in their long-term Earth systems context. Well-integrated studies of field-based and analytical data, combined with reality-driven climate modeling, offer the best hope for understanding which climate forcings may have combined to induce severe global cooling, and ultimately identify the trigger event(s) for climatic chancre, if any existed.