Archean subduction recorded by Re-Os isotopes in eclogitic sulfide inclusions in Kimberley diamonds

Richardson, S.H., Shirey, S.B., Harris, J. and Carlson, R.W. (2001) Archean subduction recorded by Re-Os isotopes in eclogitic sulfide inclusions in Kimberley diamonds. Earth and Planetary Science Letters, 191, pp. 257-266. (doi: 10.1016/S0012-821X(01)00419-8)

Abstract

Eclogitic sulfide minerals encapsulated in diamonds originating from the deepest part of the continental mantle keel beneath the Kaapvaal craton, southern Africa, and brought to the surface by the Kimberley kimberlites, show low Ni and Os contents and high Re/Os ratios characteristic of a basaltic protolith. The sulfide inclusions with the lowest Os contents give late Archean single grain absolute ages while those with higher Os contents yield a well-constrained 2.9 Ga isochron age and radiogenic initial Os isotope composition (gammaOs=+45). This indicates a significant time gap between basaltic precursor generation and eclogitic diamond crystallization, consistent with extended residence in a near-surface environment prior to subduction associated with accretion of the Kimberley block to the rest of the craton and subsequent diamond formation. These results suggest that subduction-related crustal recycling was already a viable process during continent formation in the middle Archean and may have been implicated in eclogitic diamond formation ever since.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Harris, Dr Jeff
• Authors: Richardson, S.H., Shirey, S.B., Harris, J., and Carlson, R.W.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Earth and Planetary Science Letters