hence providing insights into the composition of the upper convective mantle beneath continents. This definition does not consider Group II kimberlites or orangeites, which have been recently recognised to be carbonate-rich olivine lamproites (Mitchell, 2020;Pearson et al., 2019) and are sourced in metasomatized portions of the sub-continental lithospheric mantle (Becker & le Roex, 2006;Pearson et al., 2019). Recently, the sources of kimberlite melts have come under increased scrutiny. Woodhead et al. (2019) showed that, at least until around 200 Ma, kimberlites appear to have formed from a relatively homogeneous source with Nd-Hf isotope compositions close to the chondritic uniform reservoir (CHUR) model of Earth's primitive mantle. Giuliani et al. (2021) further argued that this source is equivalent to the PREvalent MAntle (PRE-MA) component that is widely observed in ocean island and continental basalts. However, kimberlites emplaced since 200 Ma in several large kimberlite provinces (Brazil, western Canada, southern Africa) display initial 143 Nd/ 144 Nd and 176 Hf/ 177 Hf ratios that reach significantly lower (i.e., sub-chondritic) values compared to those that have been observed to date in older kimberlites. As discussed by Woodhead et al. ( 2019), the steep Nd or Hf isotope versus time trend shown by Mesozoic (∼180-70 Ma) kimberlites in southern