Crustal xenoliths at Udachnaya pipe include both granulitic lower crust and gneissic upper crust.
Lower crustal samples have a Paleoproterozoic U–Pb zircon age.
Upper crustal samples are Neoarchaean (ca. 2.7 Ga).
The Proterozoic lower crust does not correspond to reworking of the Archaean crust.
The Archaean lithosphere was removed and replaced in the Paleoproterozoic.