Soumendu Sarkar Compositional variations of olivine in kimberlites: A new tool for diamond exploration. / Giuliani, Andrea; Phillips, David B.; Soumendu, Sarkar et al.
17TH BIENNIAL SGA MEETING, 2023. Vol. 3 2023. p. 259-261.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Research › peer-review
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TY - GEN
T1 - Soumendu Sarkar Compositional variations of olivine in kimberlites: A new tool for diamond exploration
AU - Giuliani, Andrea
AU - Phillips, David B.
AU - Soumendu, Sarkar
AU - Pearson, D. Graham
AU - Weiss, Ya.
AU - Preston, Robin
AU - Seller, Michael
AU - Spetius, Zdislav
N1 - Conference code: 17
PY - 2023
Y1 - 2023
N2 - Understanding the diamond potential of lithospheric roots traversed by kimberlites is a complex art that largely relies on geochemical and thermobarometric constraints provided by mantle-derived garnet, clinopyroxene and chromite (diamond indicator minerals). Although it is widely acknowledged that strongly melt-metasomatised lithospheric mantle keels are associated with poor diamond preservation, the mechanisms underpinning this relationship are far from clear. Here we show that the diamond grade of kimberlites worldwide is reflected by the composition of magmatic olivine. Kimberlites with low diamond grades contain iron-rich olivine, which is typical of kimberlites that entrain and assimilate substantial amounts of lithospheric mantle material metasomatised by earlier failed pulses of kimberlite (or similar) melt. Conversely, high diamond grades are exclusively associated with kimberlites featuring Mg-rich olivine composition which sampled lithospheric mantle keels only marginally modified by interaction with precursor kimberlite or related melts. This work provides a causal link between infiltration of the deep lithosphere by carbonate-rich kimberlite melts and diamond destruction, and shows that olivine chemistry is a new and inexpensive tool for diamond exploration.
AB - Understanding the diamond potential of lithospheric roots traversed by kimberlites is a complex art that largely relies on geochemical and thermobarometric constraints provided by mantle-derived garnet, clinopyroxene and chromite (diamond indicator minerals). Although it is widely acknowledged that strongly melt-metasomatised lithospheric mantle keels are associated with poor diamond preservation, the mechanisms underpinning this relationship are far from clear. Here we show that the diamond grade of kimberlites worldwide is reflected by the composition of magmatic olivine. Kimberlites with low diamond grades contain iron-rich olivine, which is typical of kimberlites that entrain and assimilate substantial amounts of lithospheric mantle material metasomatised by earlier failed pulses of kimberlite (or similar) melt. Conversely, high diamond grades are exclusively associated with kimberlites featuring Mg-rich olivine composition which sampled lithospheric mantle keels only marginally modified by interaction with precursor kimberlite or related melts. This work provides a causal link between infiltration of the deep lithosphere by carbonate-rich kimberlite melts and diamond destruction, and shows that olivine chemistry is a new and inexpensive tool for diamond exploration.
UR - https://scholar.google.com/citations?view_op=view_citation&hl=en&user=RDzPH5UAAAAJ&citation_for_view=RDzPH5UAAAAJ:_FxGoFyzp5QC
M3 - Conference contribution
SN - 978-2-8399-4046-7
VL - 3
SP - 259
EP - 261
BT - 17TH BIENNIAL SGA MEETING, 2023
T2 - 17TH SGA Biennial Meeting
Y2 - 28 August 2023 through 1 September 2023
ER -
ID: 71574911