A North American provenance for Neoproterozoic to Cambrian sandstones in Tasmania?

Tasmania forms an enigmatic province within the Neoproterozoic to Cambrian history of Australia. It lies at the boundary between Australia and North A merica in most Rodinia reconstructions but no reliable lithostratigraphic c orrelations have been reported with either mainland Australia or North Amer ica. We used detrital zircon age spectra, measured by LAM-ICP-MS, of Neopro terozoic and Cambrian sandstones in Tasmania to search for evidence of corr elations with these two continental blocks during the time slice critical t o Rodinia breakup. The Tasmanian sandstones are dominated by 1600-1900 Ma a nd 1200-1500 Ma age zircons. There is little evidence for Grenville (simila r to 1100 Ma) and Ross (similar to 550 Ma) Orogen sources in these sandston es, in contrast to detrital zircon age spectra of similar age rocks in Sout h Australia. The detrital zircon age spectra of Tasmanian sandstones are di fferent from age spectra reported from British Columbia, They are very simi lar to age spectra reported from Cambrian sandstones of Nevada, supporting Rodinia reconstructions that place southwestern USA near to Tasmania in the Neoproterozoic. (C) 2001 Elsevier Science B.V. All rights reserved.