Figure 2

Carbon isotope composition of diamonds (expressed as δ13C relative to Pee Dee Belemnite). (a) Worldwide lithospheric continental diamonds12 showing eclogitic (pink) and peridotitic diamonds (green). (b) Super-deep continental diamonds8,9,10,11 from Juina-5, Jagersfontein, Monastery, Sao Luis and Kankan. Also shown are the carbon isotope ranges for the cores and rims of the Sao-Luis8 and Juina-510 diamonds, and data reported for seven fragments of CLIPPIR diamonds36. (c) Oceanic diamonds from Mirdirta32, Pozanti-Karsanti44 and Ray-Iz30. The carbon isotope range for the mantle is from Deines48, the ranges for carbonates and organic matter are from studies of sedimentary rocks of the entire geological record49,50,51.