TY - JOUR

T1 - Composition of diamond-forming media in cuboid diamonds from the V. Grib kimberlite pipe (Arkhangelsk province, Russia)

AU - Zedgenizov, Dmitry A.

AU - Malkovets, Vladimir G.

AU - Griffin, William L.

PY - 2017/1/1

Y1 - 2017/1/1

N2 - Microinclusions in cuboid diamonds represent the mantle-derived fluid or melt from which they crystallized. The low degree of N aggregation in diamonds with microinclusions (cuboid or coated diamonds) indicates a short mantle residence and suggests that they crystallized shortly before kimberlite eruption. New data on the composition of microinclusions in cuboid diamonds from V. Grib kimberlite pipe (Arkhangelsk province, NW Russia) reveal two contrasting types: carbonatitic and hydrous-silicic. Significant variations in phase relations and in the ratios between different phases in the microinclusions of different diamonds are consistent with the potentially wider compositional variations expected for local volumes of diamond-forming fluids/melts. Compared to the host kimberlites, diamond microinclusions show a strong enrichment in K, a shallower REE profile, and pronounced depletion in Ti, Zr and Y. All microinclusions in diamonds from the V. Grib kimberlite pipe show enrichment in many incompatible elements, which supports their formation by partial melting of metasomatized mantle peridotites and eclogites. These data suggest that the diamonds have crystallized from carbonatesilicate fluids/melts that were derived from a source also common to kimberlites.

AB - Microinclusions in cuboid diamonds represent the mantle-derived fluid or melt from which they crystallized. The low degree of N aggregation in diamonds with microinclusions (cuboid or coated diamonds) indicates a short mantle residence and suggests that they crystallized shortly before kimberlite eruption. New data on the composition of microinclusions in cuboid diamonds from V. Grib kimberlite pipe (Arkhangelsk province, NW Russia) reveal two contrasting types: carbonatitic and hydrous-silicic. Significant variations in phase relations and in the ratios between different phases in the microinclusions of different diamonds are consistent with the potentially wider compositional variations expected for local volumes of diamond-forming fluids/melts. Compared to the host kimberlites, diamond microinclusions show a strong enrichment in K, a shallower REE profile, and pronounced depletion in Ti, Zr and Y. All microinclusions in diamonds from the V. Grib kimberlite pipe show enrichment in many incompatible elements, which supports their formation by partial melting of metasomatized mantle peridotites and eclogites. These data suggest that the diamonds have crystallized from carbonatesilicate fluids/melts that were derived from a source also common to kimberlites.

KW - Diamond

KW - Fluid

KW - Kimberlite

KW - Mantle

KW - Melt

KW - Microinclusions

UR - http://www.scopus.com/inward/record.url?scp=85020026107&partnerID=8YFLogxK

U2 - 10.2343/geochemj.2.0455

DO - 10.2343/geochemj.2.0455

M3 - Article

AN - SCOPUS:85020026107

VL - 51

SP - 205

EP - 213

JO - Geochemical Journal

JF - Geochemical Journal

SN - 0016-7002

IS - 3

ER -