TY - JOUR

T1 - Decarbonation reactions involving ankerite and dolomite under upper mantle p,t-parameters

T2 - Experimental modeling

AU - Bataleva, Yuliya V.

AU - Kruk, Aleksei N.

AU - Novoselov, Ivan D.

AU - Furman, Olga V.

AU - Palyanov, Yuri N.

PY - 2020/8/1

Y1 - 2020/8/1

N2 - An experimental study aimed at the modeling of dolomite-and ankerite-involving decarbonation reactions, resulting in the CO2 fluid release and crystallization of Ca, Mg, Fe garnets, was carried out at a wide range of pressures and temperatures of the upper mantle. Experiments were performed using a multi-anvil high-pressure apparatus of a “split-sphere” type, in CaMg(CO3)2-Al2O3-SiO2 and Ca(Mg,Fe)(CO3)2-Al2O3-SiO2 systems (pressures of 3.0, 6.3 and 7.5 GPa, temperature range of 950–1550◦C, hematite buffered high-pressure cell). It was experimentally shown that decarbonation in the dolomite-bearing system occurred at 1100 ± 20◦C (3.0 GPa), 1320 ± 20◦C (6.3 GPa), and 1450 ± 20◦C (7.5 GPa). As demonstrated by mass spectrometry, the fluid composition was pure CO2 . Composition of synthesized garnet was Prp83Grs17, with main Raman spectroscopic modes at 368–369, 559–562, and 912–920 cm−1 . Decarbonation reactions in the ankerite-bearing system were realized at 1000 ± 20◦C (3.0 GPa), 1250 ± 20◦C (6.3 GPa), and 1400 ± 20◦C (7.5 GPa). As a result, the garnet of Grs25Alm40Prp35 composition with main Raman peaks at 349–350, 552, and 906–907 cm−1 was crystallized. It has been experimentally shown that, in the Earth’s mantle, dolomite and ankerite enter decarbonation reactions to form Ca, Mg, Fe garnet + CO2 assemblage at temperatures ~175–500◦C lower than CaCO3 does at constant pressures.

AB - An experimental study aimed at the modeling of dolomite-and ankerite-involving decarbonation reactions, resulting in the CO2 fluid release and crystallization of Ca, Mg, Fe garnets, was carried out at a wide range of pressures and temperatures of the upper mantle. Experiments were performed using a multi-anvil high-pressure apparatus of a “split-sphere” type, in CaMg(CO3)2-Al2O3-SiO2 and Ca(Mg,Fe)(CO3)2-Al2O3-SiO2 systems (pressures of 3.0, 6.3 and 7.5 GPa, temperature range of 950–1550◦C, hematite buffered high-pressure cell). It was experimentally shown that decarbonation in the dolomite-bearing system occurred at 1100 ± 20◦C (3.0 GPa), 1320 ± 20◦C (6.3 GPa), and 1450 ± 20◦C (7.5 GPa). As demonstrated by mass spectrometry, the fluid composition was pure CO2 . Composition of synthesized garnet was Prp83Grs17, with main Raman spectroscopic modes at 368–369, 559–562, and 912–920 cm−1 . Decarbonation reactions in the ankerite-bearing system were realized at 1000 ± 20◦C (3.0 GPa), 1250 ± 20◦C (6.3 GPa), and 1400 ± 20◦C (7.5 GPa). As a result, the garnet of Grs25Alm40Prp35 composition with main Raman peaks at 349–350, 552, and 906–907 cm−1 was crystallized. It has been experimentally shown that, in the Earth’s mantle, dolomite and ankerite enter decarbonation reactions to form Ca, Mg, Fe garnet + CO2 assemblage at temperatures ~175–500◦C lower than CaCO3 does at constant pressures.

KW - Ankerite

KW - CO fluid

KW - Decarbonation reaction

KW - Dolomite

KW - Experimental modeling

KW - Garnet

KW - High-pressure experiment

KW - SYSTEM

KW - HIGH-PRESSURE

KW - high-pressure experiment

KW - garnet

KW - MELTS

KW - MINERAL INCLUSIONS

KW - TRANSITION ZONE

KW - CARBONATE

KW - ankerite

KW - decarbonation reaction

KW - DIAMOND FORMATION

KW - dolomite

KW - CO2 fluid

KW - experimental modeling

KW - PHASE-RELATIONS

KW - SIDERITE STABILITY

KW - KIMBERLITE PIPE

UR - http://www.scopus.com/inward/record.url?scp=85090532742&partnerID=8YFLogxK

U2 - 10.3390/min10080715

DO - 10.3390/min10080715

M3 - Article

AN - SCOPUS:85090532742

VL - 10

SP - 1

EP - 17

JO - Minerals

JF - Minerals

SN - 2075-163X

IS - 8

M1 - 715

ER -