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The geodynamic processes and the chemical and thermal evolution of the mantle beneath the Kaapvaal craton (South Africa) was investigated with further regard to diamond formation. For this, 31 coarse-grained peridotites and 21 individual subcalcic garnets from heavy mineral concentrates (HMC) from the Finsch mine were studied for their major and trace element compositions, Lu-Hf and Sm-Nd isotope composition. Furthermore, processes in the Earth’s mantle that follow kimberlite sampling and propagation were studied in polymict peridotite breccia from Kimberley mines. Inter mineral equilibrium of the peridotites was tested by comparing the results from different, independent thermometers. These, well equilibrated peridotites stem from a restricted pressure of 5 to 6.5 GPa (depth ~160-200 km) and a temperature range of 1050-1250°C, following the 40 mW/m2 conductive geotherm. The majority of the samples display a well developed anti-correlation of oxygen fugacity with pressure, which is in contrast to the sheared and oxidised, younger kimberlite erupted peridotites from Kimberley. All analysed samples have homogeneous trace element mineral chemistry. Variations in trace elements among Finsch peridotites reflect their complex nature and the intricate development of the subcratonic mantle. The 3.6 Ga is the oldest crustal age recorded in the Kaapvaal craton, and is confirmed by the Lu-Hf model age of a highly radiogenic subcalcic garnet in this study. Therefore, this age probably represents the oldest depletion (partial melting event) of the subcratonic mantle beneath the Kaapvaal craton. Both, subcalcic garnets and Finsch peridotites yield Lu-Hf isochron ages of around 2.5 Ga, which probably represent the last depletion event of the Kaapvaal craton. Several older (than 2.5 Ga) depletions were also necessary to explain higher isochron initials of the both isochrones. The Cr# and HREE concentrations and ratios of the Finsch subcalcic garnets and peridotites indicate that partial melting of the Kaapvaal craton happened at different depths. One group of subcalcic garnets (group-1) experienced depletion at high pressure in the garnet stability field and another one (group-2) at low pressures in the spinel or plagioclase stability field. Major and trace elements indicate that up to 50%, of the melt was remover from the primitive (primer) mantle in at least two melting events. Thus, first continental crust was created early (> 2.5 Ga) from high degrees of partial melting of the lithospheric mantle. According to the Sm-Nd isotope signatures at least two metasomatic events took place significantly after 2.5 Ga. As monitored by group-1 subcalcic garnets, the first enrichment was produced by a fluid and occurred at around 1.3 Ga. The second metasomatic event was much later at 500-300 Ma ago and has changed both Nd and Hf isotopic compositions of group-2 subcalcic garnet as well as some Finsch peridotites. During partial melting any carbon species will be dissolved in the melt and removed from the residue. Therefore, any diamond growth before the last depletion (~2.5 Ga) would have been probably completely removed from the lithospheric mantle. Consequently, carbon was apparently reintroduced into the system, i.e. during Metasomatism, and triggered the growth of diamonds. The Sm-Nd isotope systematics of the subcalcic garnets of this study indicates that enrichment occurred at ~1.3 Ga or later, which implies non-Archean, late diamond growth in Finsch. Fertilisation of the subcontinental craton associated with the percolation of group-2 (~120 Ma) or even younger (~90 Ma) group-1 kimberlites and their precursors are not observed in Finsch peridotites, but are well presented in mantle xenoliths from Kimberley. Therefore, these younger events were studied on specific mantle xenoliths, polymict breccia from Kimberley. A polymict peridotite found at the Boshof road dump, Kimberley, represents a mechanical mixture of upper mantle clasts and minerals (opx, cpx, garnet and olivine) of different lithologies, cemented by fine-grained olivine and minute amounts of interstitial ilmenite, phlogopite and sulphide. According to Ni in garnet thermometry, single porphyroclastic garnets were sampled and mixed during ascent in a 100 km stratigraphic column, starting from ~250 km until ~120 km. During this ascent, melt has reacted with the porphyroclasts and at theirrims neoblastic minerals were formed, i.e. neoblastic opx around opx porphyroclast, neoblastic garnet around garnet porphyroclast, and neoblastic opx around cpx porphyroclast. Analyses of those neoblastic minerals indicate that volatile-rich, kimberlite-like melt was the agent that collected the mantle minerals and amalgamated this xenolith. Several complex processes were responsible for the formation of the polymict breccia. They comprise melt degassing at high pressures that probably created “explosive” Brecciation of the cratonic roots (~250 km), propagation of the melt that collected different porphyroclasts on a way and amalgamation at around 120 km. The whole process of “explosive” brecciation, turbulent transport and mixing of mantle porphyroclasts and melt, porphyroclast dissolution and neoblast precipitation happened very fast and was part of the kimberlite formation. Therefore, the here studied sample probably represents one frozen part (with variable mantle clasts) of the kimberlitic magma precursor, with kimberlite eruption at ~90 Ma years ago in Kimberley.