The Kalahari Craton: Clifford’s Rule Reflects Diamond’s Ancient Origins

Diamonds with peridotitic and eclogitic assemblages of the inclusions in kimberlites of the Kalahari Craton occur almost equal in amount, often together in the same pipes. The model ages of the inclusion minerals of peridotitic assemblage exceed often 3.2 Ga, while the eclogitic inclusions are variable, but younger – 2,700-90 Ma (Proterozoic). It is attributed to the diamonds and associate minerals transportation being sampled of the deep roots underlying the cratonic areas, being peridotitic (predominantly harzburgitic) in composition and evolving as some kind of restites under major melting events in mantle around 3.5 Ga.