Relationship between fluid end-members and noble gases in South African diamonds

Date & time

12.30–1.30pm 11 August 2017


Ringwood Room, J4


Suzette Timmerman


 Michael Anenburg
 0451 406 232

Fibrous diamond growth zones can contain abundant high density fluid inclusions (HDFs) and these provide the most direct information on the source and composition of diamond-forming fluids. Four different fluid end-members have been defined; silicic, low-Mg carbonatitic, high-Mg carbonatitic, and saline. Continuous arrays exist between the silicic and low-Mg carbonatitic end-member and between the saline and high-Mg carbonatitic end-member. Different processes have been proposed to explain the two major element compositional arrays, but the origin of and relation between the various fluid end-members is still uncertain. In this study we provide new constraints on the evolution and origin of these diamond-forming fluids by combining noble gas systematics with δ13C, N concentrations, and fluid inclusion compositions.

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