Australia: The Land Where Time Began

A biography of the Australian continent 

Calibrating the Cryogenian

According to the authors¹ the scarcity of direct and precise constraints on the age of the strata from the Neoproterozoic has prevented the complete integration of the great environmental and biological changes that took place in this era. In this paper the authors¹ present 4 high-precision U-Pb ages that constrain large perturbations in the carbon cycle, a major diversification and depletion in the record of microfossils, and the onset of the Sturtian Glaciation, in the Neoproterozoic rocks from northwestern Canada. The Franklin Large Igneous Province and palaeomagnetic poles that place Laurentia in an equatorial location, is synchronous with the age of Sturtian glacial deposits, interbedded with volcanic tuff, that have been dated to 716.5 Ma. The Sturtian Glaciation is therefore indicated by icebergs grounded below sea level at very low palaeolatitudes to have been of global extent.

Sources & Further reading

1. Macdonald, Francis A., Mark D. Schmitz, James L. Crowley, Charles F. Roots, David S. Jones, Adam C. Maloof, Justin V. Strauss, et al. "Calibrating the Cryogenian." Science 327, no. 5970 (March 5, 2010 2010): 1241-43.