Vaalbara, Earth’s oldest assembled continent? A combined structural, geochronological, and palaeomagnetic test

Abstract

The only remaining areas of pristine 3.6–2.7 Ga crust on Earth are parts of the Kaapvaal and Pilbara cratons. General similarities of their rock records, especially of the overlying late Archean sequences, suggest that they were once part of a larger Vaalbara supercontinent. Here we show that the present geochronological, structural and palaeomagnetic data support such a Vaalbara model at least as far back as 3.1 Ga, and possibly further back to 3.6 Ga. Vaalbara fragmented prior to 2.1 Ga, and possibly as early as 2.7 Ga, suggesting supercontinent stability of at least 400 Myr, consistent with Neoproterozoic and Phanerozoic analogues.

U–Pb geochronology and paleomagnetism of the Westerberg Sill Suite, Kaapvaal Craton – Support for a coherent Kaapvaal–Pilbara Block (Vaalbara) into the Paleoproterozoic?

“…The volcanic rocks of the Ventersdorp Supergroup and the sedimentary rocks of the successive Transvaal Supergroup (Kaapvaal Craton), can be correlated with the volcanic rocks of the Fortescue Group and the sedimentary rocks of the Mount Bruce Supergroup (Pilbara Craton), respectively (Cheney, 1990). A comparison between similar poles of the Neoarchean Usushwana Complex on the Kaapvaal Craton, and the Millindina Complex (Pilbara Craton), in addition to correlation between Archean tectonic architecture of the respective cratons, led Zegers et al (1998) to propose an alternative reconstruction with the Pilbara Craton on the eastern margin of the Kaapvaal Craton. Published paleomagnetic data disproved the traditional "Cheney-fit" scenario; De Kock et al (2009a) revised paleomagnetic results for the 2.78-2.70 Ga interval, and also presented new data from the Ventersdorp Supergroup volcanic rocks.…”

“…The NeoarcheanPaleoproterozoic continuity of these two cratons (i.e., Vaalbara) was first proposed by Cheney et al (1988). The exact configuration of the two cratons at this time has since been tested (Smirnov et al, 2013;De Kock et al, 2009a;Strik et al, 2003;Wingate, 1998;Zegers et al, 1998). Vaalbara is currently paleomagnetically well constrained between ca.…”

Baddeleyite U–Pb ages and gechemistry of the 1875–1835 Ma Black Hills Dyke Swarm across north-eastern South Africa: part of a trans-Kalahari Craton back-arc setting?

“…Even if the associated Tsineng dyke swarm extrapolates towards the outlined Soutpansberg "sub-province", its ENE-trend is slightly oblique to the more northerly trending BHDS. Cornell et al (1998), furthermore, on mafic rocks of appropriate age on the Australian continent; e.g., in order to determine whether Pilbara resided along Kaapvaal's eastern "passive" margin (Zegers et al 1998) or its western margin, as suggested by de Kock et al's (2009) "Vaalbara" concept.…”

Palaeoproterozoic supercontinents and global evolution: correlations from core to atmosphere

“…Three supercratons were exemplified and distinguished by age of cratonization: Vaalbara (2.9 Ga), Superia (2.7 Ga), and Sclavia (2.6 Ga). Vaalbara has the longest history of recognition and palaeomagnetic testing (Cheney 1996;Wingate 1998;Zegers et al 1998) with the most recent tests allowing a direct juxtaposition (Strik et al 2003;de Kock et al 2009). Superia has become more completely specified by the geometric constraints of precisely dated, intersecting dyke swarms across Superior, Kola -Karelia, Hearne, and Wyoming cratons through the interval 2.5-2.1 Ga (Bleeker & Ernst 2006).…”