A 182W isotope perspective on the sources of Paleoarchean TTGs from the Eastern Kaapvaal Craton, southern Africa

¹⁸²W deficits in terrestrial rocks are currently strongly debated since their origin can be ascribed to different processes. These include (1) core-mantle interaction, (2) grainy late accretion, and (3) early silicate differentiation. Mantle-derived rocks from the eastern Kaapvaal Craton yield variably negative µ¹⁸²W values that are systematically correlated with initial values of the long-lived Hf-Nd-Ce isotope systems. These have been interpreted to reflect incorporation of an early Hadean crustal restite either in the deep mantle sources of Archean mantle plumes or within the upper mantle or lower lithosphere of the Kaapvaal Craton. Interestingly, granitoids from the Kaapvaal Craton are either overlapping with the modern ¹⁸²W isotope composition or carry a strongly negative µ¹⁸²W of down to -10, overlapping with Mesoarchean diamictites from the Kaapvaal Craton. Deviation of some granitoids from the Kaapvaal ¹⁸²W-¹⁷⁶Hf and ¹⁸²W-¹⁴³Nd array are likely caused by disturbance of the whole-rock Hf-Nd data or by fluid mobility of W. Here we will further explore the ¹⁸²W isotope composition of the Paleoarchean Ngwane Gneiss suite from the Ancient Gneiss Complex (Eswatini) and TTG plutons from the Barberton Mountain Land, that reveal a time-integrated increase of initial epsHf values in magmatic zircon. Our results provide further constraints on the origin of granitoids that plot at the upper end of the µ¹⁸²W-epsHf array. We will present first 182W data produced on the NEOMA MC-ICPMS in Berlin, which have a high level of accuracy as revealed by replicate measurments from samples previously measured at University of Cologne.