Composition of primary kimberlite magma: constraints from melting and diamond dissolution experiments

被引:20
作者
Sokol, A. G. [1 ,2 ]
Khokhryakov, A. F. [1 ]
Palyanov, Yu. N. [1 ]
机构
[1] Russian Acad Sci, VS Sobolev Inst Geol & Mineral, Siberian Branch, Novosibirsk 630090, Russia
[2] Novosibirsk State Univ, Novosibirsk 630090, Russia
基金
俄罗斯科学基金会;
关键词
Experiment Mantle; Kimberlite; Magma; Water; Fluid; Diamond dissolution; Etch forms; CARBONATE-SILICATE MELTS; GROUP-II KIMBERLITES; OXYGEN FUGACITY; HIGH-PRESSURE; LITHOSPHERIC MANTLE; UDACHNAYA KIMBERLITE; FLUID COMPOSITION; HIGH-TEMPERATURES; OXIDATION-STATE; EARTHS MANTLE;
D O I
10.1007/s00410-015-1182-z
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Experiments are applied to constrain the composition of primary kimberlitic magmas which were in equilibrium with lithospheric peridotite and could resorb the entrained diamond to form typical dissolution features. The experiments are run on samples of a model carbonatite and a melt of the Udachnaya kimberlite at 6.3 GPa and 1400 degrees C, and at unbuffered or Re ReO2-buffered oxygen fugacity (1-2 log units above Ni-NiO). Near-liquidus dry Fe3+-free carbonatitic melt (derived from carbonated harzburgite) is saturated with the Ol-Grt-Opx-Mgs assemblage and is almost inert to diamond. Carbonatitic melts that bear 4.6-6.8 wt% Fe2O3 or 1.5 wt% H2O are in equilibrium only with Mgs +/- ol near the liquidus. Dissolution of diamond by these melts produces surface textures uncommon (corrosion sculptures) or common (negative-oriented trigons, shield-shaped laminae and elongate hillocks) to kimberlitic diamonds. The near-liquidus melt of the Udachnaya kimberlite (Yakutia) with 10-12 wt% H2O is saturated with the Ol-Grt-Cpx assemblage and may result from melting of carbonated garnet-bearing wehrlite. Hydrous kimberlitic melt likewise resorbs diamonds forming typical negative-oriented trigons, shield-shaped laminae and elongate hillocks on their surfaces. Therefore, the melts that could originate in the thermal conditions of subcratonic lithosphere, entrain diamond and dissolve it to produce dissolution features on crystal surfaces, were compositionally close to kimberlite (16-19 wt% SiO2) and rich in H2O. Dry Fe3+-bearing carbonatites with fO(2) controlled by the ferric/ferrous equilibrium slightly above the Ni-NiO buffer cannot be diamond carriers.
引用
收藏
页数:18
相关论文
共 81 条
  • [1] [Anonymous], OXIDATION NATURAL DI
  • [2] OXIDATION-STATES OF THE UPPER MANTLE RECORDED BY MEGACRYST ILMENITE IN KIMBERLITE AND TYPE-A AND TYPE-B SPINEL IHERZOLITES
    ARCULUS, RJ
    DAWSON, JB
    MITCHELL, RH
    GUST, DA
    HOLMES, RD
    [J]. CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, 1984, 85 (01) : 85 - 94
  • [3] ARIMA M, 1993, GEOLOGY, V21, P968, DOI 10.1130/0091-7613(1993)021<0968:CODFAS>2.3.CO
  • [4] 2
  • [5] Conditions for the origin of oxidized carbonate-silicate melts: Implications for mantle metasomatism and diamond formation
    Bataleva, Y. V.
    Palyanov, Y. N.
    Sokol, A. G.
    Borzdov, Y. M.
    Palyanova, G. A.
    [J]. LITHOS, 2012, 128 : 113 - 125
  • [6] Geochemistry of South African on- and off-craton, Group I and Group II kimberlites: Petrogenesis and source region evolution
    Becker, M
    Le Roex, AP
    [J]. JOURNAL OF PETROLOGY, 2006, 47 (04) : 673 - 703
  • [7] TECHNIQUES FOR CONTROL OF WATER FUGACITY AND OXYGEN FUGACITY FOR EXPERIMENTATION IN SOLID-MEDIA HIGH-PRESSURE APPARATUS
    BOETTCHER, AL
    MYSEN, BO
    ALLEN, JC
    [J]. JOURNAL OF GEOPHYSICAL RESEARCH, 1973, 78 (26): : 5898 - 5901
  • [8] Composition of the Siberian cratonic mantle: evidence from Udachnaya peridotite xenoliths
    Boyd, FR
    Pokhilenko, NP
    Pearson, DG
    Mertzman, SA
    Sobolev, NV
    Finger, LW
    [J]. CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, 1997, 128 (2-3) : 228 - 246
  • [9] Experimental melting of carbonated peridotite at 610 GPa
    Brey, Gerhard P.
    Bulatov, Vadim K.
    Girnis, Andrei V.
    Lahaye, Yann
    [J]. JOURNAL OF PETROLOGY, 2008, 49 (04) : 797 - 821
  • [10] Melting of K-rich carbonated peridotite at 6-10 GPa and the stability of K-phases in the upper mantle
    Brey, Gerhard P.
    Bulatov, Vadim K.
    Girnis, Andrei V.
    [J]. CHEMICAL GEOLOGY, 2011, 281 (3-4) : 333 - 342