UPb zircon and SmNd geochronology of the Mesoproterozoic of North Queensland: implications for a Rodinian connection with the Belt supergroup of North America

Abstract

UPb zircon SHRIMP age dates and SmNd isotopic compositions are reported for a number of samples of Proterozoic metasedimentary and meta-igneous rocks from a range of geological provinces in North Queensland. The new data focus on the connection between east Australia and Laurentia (North America) in the Rodinian Supercontinent. One of the keys to the Rodinian reconstruction has been the nature and location of the source area of the Mesoproterozoic Belt Supergroup (North America). Most workers consider local derivation unlikely and Australia as the candidate. The source area requirements that are not satisfied by local derivation are: zircon populations of ca. 1590 Ma (in the Revett Formation of Lower Belt Supergroup) and ca. 1070–1200 Ma Grenvillian age [in the Deer Trail Group equivalent(?) to the top of Belt Supergroup]; and crustal residence ages ( T DM) of dominantly Palaeoproterozoic crust (1.97-2.14 Ga). Our study has shown that North Queensland contains appropriate zircon, and crustal residence times to match the ‘missing’ source area for the Belt Supergroup. The ca. 1590 Ma component of the Revett Formation is common in the Yambo Subprovince, and the 1690 Ma zircon in the Forsayth Subprovince is suitable for the Missoula Group. Both the Yambo and Forsayth Subprovinces contain a range of detrital zircons up to 2700 Ma (e.g. 1776, 1820, 1886, 2100, 2250, 2305, 2640, 2660 and 2700 Ma). For the Deer Trail Group, Grenvillian zircons occur in the Cape River Province (1238, 1145 and 1105 Ma) and in the Iron Range Province (∼1200 Ma). T DM young to the north and northeast, with the Savannah Province and Yambo Subprovince yielding ages between about 2.1 and 2.44 Ga.