U-Pb age of Kaapvaal craton titanite: geotectonic interpretation and correlation with the Karelian craton

Abstract

The results of dating of Kaapvaal Craton titanite are reported. It is shown that metamorphiczircon, apatite, amphibole and garnet in the Neoarchaean tectono-thermal activation belt in the eastern Swaziland terrane have an age of ca. 2.74 Ga, while the age of titanite outside the belt is Palaeo-Mesoarchaean (3.21–3.16 Ga), similar to the time of formation of post-kinematic K-granite consistent with a cratonization stage. Titaniteoccurring in the western periphery of the Vodlozero terrane in the Karelian Craton is also Neoarchaean (2.74–2.63 Ga), correlating with the main phase of accretion processes there. Titanite in the central part of the terrane shows an age of 2.87–2.86 Ga, suggesting that the crust began to stabilize at that time. The ages of old titanites from the Kaapvaal and Karelian Cratons (3.21–3.16 and 2.87–2.86 Ga, respectively) correlate with the time of early crustal cratonization, while younger titanites date back to the time of Neoarchaeantectono-thermal activation and this dating indirectly supports the assumption that both cratons were part of one Neoarchaean Kenorland Supercontinent. Correlation of the resultsobtained for the two cratons has led the authors to conclude that the age of titanites is a reliable indicator of the time of late tectono-thermal processes.

Keywords

• геохронология
• u-pb метод
• титанит
• архей, каапваальский кратон
• карельский кратон, свазиленд, водлозерский террейн