Australia: The Land Where Time Began

A biography of the Australian continent 

Glaciation on Baltica in the Late Neoproterozoic - the Timing Constrained by Detrital Zircon from Geochronology in the Hedmark Group, Southeast Norway

According to the authors¹ in the Hedmark Group, southeast Norway, the Moelv Tillite is a glacial deposit of the Varanger Glaciation of the Late Neoproterozoic. Samples collected on the detrital zircons in the Rendalan Formation, that underlies the Moelv Tillite, were analysed by paired U-Pb and Lu-Hf techniques and the resulting data uncovered an uncommon 677 ± 15 Ma to 620 ± 14 Ma population that constrain the Moelv Tillite to be younger than 620 ± 14 Ma. The authors¹ suggest the youngest detrital zircons may derived from granite magmatism that is related to the Egersund Dolerite magmatism dated to 616 ± 3 Ma, that is located in the western part of the Sveconorwegian Orogen. The Moelv Tillite has no cap carbonate, could possibly correlate with the Squantum-Gaskiers glacial deposit, from about 580 Ma, on Avalonia. It is suggested by available palaeomagnetic data of the Late Neoproterozoic that between 620 and 555 Ma Baltica was situated at medium to high latitude.

Sources & Further reading

1. Bingen, B., W. L. Griffin, T. H. Torsvik, and A. Saeed. "Timing of Late Neoproterozoic Glaciation on Baltica Constrained by Detrital Zircon Geochronology in the Hedmark Group, South-East Norway." Terra Nova 17, no. 3 (2005): 250-58.