Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Diamond-rich placer deposits from iron-saturated mantle beneath the northeastern margin of the Siberian Craton. / Shatsky, Vladislav S.; Ragozin, Alexey L.; Logvinova, Alla M. и др.
в: Lithos, Том 364-365, 105514, 07.2020.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Diamond-rich placer deposits from iron-saturated mantle beneath the northeastern margin of the Siberian Craton
AU - Shatsky, Vladislav S.
AU - Ragozin, Alexey L.
AU - Logvinova, Alla M.
AU - Wirth, Richard
AU - Kalinina, Viktoria V.
AU - Sobolev, Nikolay V.
PY - 2020/7
Y1 - 2020/7
N2 - We demonstrate for the first time the presence of iron carbides in placer diamonds from the northeastern region of the Siberian craton. It was found that the inclusions are polycrystalline aggregates, and iron carbides filling the fissures in the diamonds, thus providing clear evidence that the iron melts were captured first. Iron carbides were identified in diamonds containing mineral inclusions of eclogitic (Kfs, sulfide) and peridotitc (olivine) paragenesis. Iron carbides with minor amounts of admixed nickel were detected in a diamond sample containing an olivine inclusion (0.3 wt% Ni), indicating that the iron melt was not in equilibrium with the mantle peridotite.The low nickel contents of the iron carbides provide the best evidence that the subducted crust is a likely source of the iron melt. Diamonds containing carbide inclusions are characterised by a relatively low nitrogen aggregation state (5–35%), which is not consistent with the high temperature of the transition zone. Therefore, we have reason to assume that the studied diamonds are from the lower regions of the lithosphere. Considering all factors, the model for the interaction of the ascending asthenospheric mantle with the subducting slab seems to be more realistic.
AB - We demonstrate for the first time the presence of iron carbides in placer diamonds from the northeastern region of the Siberian craton. It was found that the inclusions are polycrystalline aggregates, and iron carbides filling the fissures in the diamonds, thus providing clear evidence that the iron melts were captured first. Iron carbides were identified in diamonds containing mineral inclusions of eclogitic (Kfs, sulfide) and peridotitc (olivine) paragenesis. Iron carbides with minor amounts of admixed nickel were detected in a diamond sample containing an olivine inclusion (0.3 wt% Ni), indicating that the iron melt was not in equilibrium with the mantle peridotite.The low nickel contents of the iron carbides provide the best evidence that the subducted crust is a likely source of the iron melt. Diamonds containing carbide inclusions are characterised by a relatively low nitrogen aggregation state (5–35%), which is not consistent with the high temperature of the transition zone. Therefore, we have reason to assume that the studied diamonds are from the lower regions of the lithosphere. Considering all factors, the model for the interaction of the ascending asthenospheric mantle with the subducting slab seems to be more realistic.
KW - Diamond
KW - Iron carbide inclusions
KW - Mantle
KW - Siberian craton
KW - Subducted crust
KW - MATO-GROSSO
KW - JUINA AREA
KW - HIGH-PRESSURE
KW - OXYGEN FUGACITY
KW - CARBON
KW - ION-BEAM FIB
KW - EARTHS MANTLE
KW - PHASE-COMPOSITION
KW - NITROGEN
KW - FE-C SYSTEM
UR - http://www.scopus.com/inward/record.url?scp=85082923447&partnerID=8YFLogxK
U2 - 10.1016/j.lithos.2020.105514
DO - 10.1016/j.lithos.2020.105514
M3 - Article
AN - SCOPUS:85082923447
VL - 364-365
JO - Lithos
JF - Lithos
SN - 0024-4937
M1 - 105514
ER -
ID: 23982633