Diamonds in Antarctica? Discovery of Antarctic kimberlites extends vast Gondwanan Cretaceous kimberlite province

Kimberlites are a volumetrically minor component of the Earth’s volcanic record, but are of great importance as the major commercial source of diamonds and as the deepest samples of the Earth’s mantle. They were predominantly emplaced into ancient, stable regions of continental crust, known as cratons, from ≈2000 Ma to ≈10 ka ago but are also known from continental rifts and mobile belts. Kimberlites have been reported from all major cratons on all continents except for Antarctica. We report here the first bona fide Antarctic kimberlite occurrence, from the northern Prince Charles Mountains, emplaced as a result of reactivation of the Lambert Graben during rifting of India from Australia-Antarctica. The samples exhibit the textural, mineralogical and geochemical features typical of Group I kimberlites from more classical localities. The ages of the nPCM kimberlites, based on radiometric dating (120 Ma), overlap with many kimberlites and related rocks from other localities on the Gondwanan continents. This discovery extends a 135-115 Ma Gondwanan kimberlite province, for the first time, into Antarctica. The kimberlites’ emplacement reflects tectono-magmatic processes associated with Cretaceous rifting between the India and Antarctica-Australia.