Please cite this article in press as: Betts, P.G., et al., Comparing 1800–1600 Ma accretionary and basin processes in Australia and Laurentia: Possible geographic connections in Columbia, Precambrian Res. (2008), doi:10.1016/j.precamres.2007.03.007 ARTICLE IN PRESS G Model PRECAM-2940; No. of Pages 12 Precambrian Research xxx (2008) xxx–xxx Contents lists available at ScienceDirect Precambrian Research journal homepage: www.elsevier.com/locate/precamres Comparing 1800–1600Ma accretionary and basin processes in Australia and Laurentia: Possible geographic connections in Columbia P.G. Betts a,∗ , D. Giles b , B.F. Schaefer a a School of Geosciences, Australian Crustal Research Centre, Monash University, Melbourne 3800, Australia b Centre for Mineral Exploration Under Cover, School of Earth and Environmental Sciences, University of Adelaide, Australia article info Article history: Received 22 May 2006 Received in revised form 26 October 2006 Accepted 30 March 2007 Keywords: Australia Laurentia Proterozoic Columbia Crustal reworking Accretion Basin evolution abstract We focus on potential pinning points on the southern and eastern margins of Australia and the southern and western margins of Laurentia and interpret a convergent plate boundary along the southern margin of the proto-Australian continent during the Palaeo- to Mesoproterozoic (1800–1600 Ma). Specific geological events within the southern Australian margin can be correlated with events preserved along the Medicine Bow–Yavapai–Mazatzal Belt in southwestern Laurentia. These belts were characterised by southward con- tinental growth with varying degrees of crustal reworking and accretion of juvenile material. In Australia crustal reworking appears to have been the dominant process from 1800 to 1670Ma, with more juvenile material accreted at 1620Ma. In contrast, the Southern Laurentian terranes were dominated by accre- tion of juvenile material from 1800 to 1620 Ma, although reworked continental crust was also accreted to the margin. In the interior of both continents basins developed with comparable histories from 1800 to 1670Ma. Thereafter the evolution of the interior basins diverged, with sag-phase processes dominant in Northern Australia and a protracted depositional hiatus in Laurentia. The geologic evolution is consistent with palaeomagnetic data and provides further evidence for geographic links between Eastern Australia and Western Laurentia from 1800 to 1600Ma. © 2008 Elsevier B.V. All rights reserved. 1. Introduction In the last two decades apparent correlations of geologic events between Australia and Laurentia have been used to argue for a link between the two continents as central components in the Neoproterozoic supercontinent Rodinia (Bell and Jefferson, 1987; Dalziel, 1991; Hoffman, 1991; Moores, 1991; Brookfield, 1993; Ross et al., 1992; Karlstrom et al., 2001; Wingate et al., 2002). How- ever, recently published palaeomagnetic data is inconsistent with their connectivity in the vital period for Rodinia reconstructions, between 1.3 and 0.80Ga (Wingate et al., 2002). Many of the correlated geological events between Australia and Laurentia pre-date and are not relevant to the proposed “Grenvil- lian” (ca. 1300–1000 Ma) assembly of Rodinia (e.g., Hoffman, 1991; Rivers, 1997). These correlations suggest that Australia and Lauren- tia may have been fellow travellers between 1900 and 1450 Ma (see Hoffman, 1991; Karlstrom et al., 2001; Idnurm and Giddings, 1995), in the period relevant to the proposed supercontinent Columbia (Rogers and Santosh, 2002; Zhao et al., 2002). Interpreted links between Laurentia and Australia during this period have been ∗ Corresponding author. Tel.: +61 3 9905 4150; fax: +61 3 9905 4903. E-mail address: Peter.Betts@sci.monash.edu.au (P.G. Betts). strengthened by tectonic interpretations that the southern mar- gins of both continents were characterised by episodic accretion of crustal material between 1800 and 1600Ga (Hoffman, 1988; Duebendorfer and Houston, 1987; Karlstrom and Bowring, 1988; Condie, 1992; Karlstrom et al., 1999, 2001; Duebendorfer et al., 2001; Swift and Force, 2001; Eisele and Isachsen, 2001; Giles et al., 2002, 2004; Betts et al., 2002; Scrimgeour et al., 2005; Betts and Giles, 2006). Despite the strong body of evidence that suggests that Australia and Laurentia occupied a similar tectonic environment during the Late Palaeoproterozoic, until recently the geochrono- logical resolution on either continent has not been sufficient to specifically correlate individual events. In this paper we compare the timing and processes responsi- ble for accretion of crustal material along the southern margin of the Australian and Laurentian continents (Fig. 1) with a view to correlate their geological evolution and therefore provide a time- integrated reconstruction of the Australia and Laurentia between 1800 and 1600 Ma. We compare the evolution of basins in the inte- rior of both continents and their plate margin evolutions. We then compare and contrast the Sm–Nd isotopic evidence from each of the belts to assess the mechanisms and modes of crustal growth and reworking between the two continents during the Late Palaeopro- terozoic. This evolution is consistent with plate reconstructions that place Eastern Australia adjacent to Western Laurentia in the Late 0301-9268/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.precamres.2007.03.007