Age, origin and composition of the Attawapiskat lithospheric mantle and its diamonds (western Superior craton, Canada).

摘要

This study reports results from peridotitic and eclogitic xenoliths and diamond samples from the Attawapiskat area to understand the processes of craton formation and modification in the Superior lithospheric mantle. These diamondiferous kimberlites also provide an opportunity to study the association of a primary diamond deposit (Victor) with a post-Archaean rift system---the Midcontinent Rift which impacted the southern Superior at ∼ 1.1 Ga. Existence of a depleted mantle reservoir beneath the Attawapiskat area since the Palaeoarchaean is indicated by TRD ages in sulphides and PGE's trapped in olivine. Mg