Experimental investigation of the mechanism of the reaction: 1 tremolite+11 dolomite ? 8 forsterite+13 calcite+9 CO2+1H2O

Heinrich, Wilhelm; Metz, Paul; Bayh, W.

doi:10.1007/bf00371323

Cited by 13 publications

(3 citation statements)

References 28 publications

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“…Our investigations were conducted on a natural dolomite sample with stoichiometry CaMg0.98Fe0.02(CO3)2 [29]. The phase-purity of the sample was checked with X-ray diffraction measurements at ambient conditions.…”

Section: Methodsmentioning

confidence: 99%

Effects of hydrostaticity on the structural stability of carbonates at lower mantle pressures: the case study of dolomite

Efthimiopoulos

Germer

Jahn

et al. 2018

High Pressure Research

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We have conducted high pressure far-infrared absorbance and Raman spectroscopic investigations on a natural iron-free dolomite sample up to 40 GPa. Comparison between the present observations and literature results unraveled the effect of hydrostatic conditions on the high pressure dolomite polymorph adopted close to 40 GPa, i.e. the triclinic Dol-IIIc modification. In particular, non-hydrostatic conditions impose structural disorder at these pressures, whereas hydrostatic conditions allow the detection of an ordered Dol-IIIc vibrational response. Hence, hydrostatic conditions appear to be a key ingredient for modeling carbon subduction at lower mantle conditions. Our complementary first-principles calculations verified the far-infrared vibrational response of the ambient-and high-pressure dolomite phases.

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Section: Methodsmentioning

confidence: 99%

Effects of hydrostaticity on the structural stability of carbonates at lower mantle pressures: the case study of dolomite

Efthimiopoulos

Germer

Jahn

et al. 2018

High Pressure Research

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“…Mineral powders are commonly used to determine reaction rates experimentally (Dachs and Metz 1988;Heinrich et al 1986Heinrich et al , 1989Kase and Metz 1980;Kridelbaugh 1973;Lüttge andMetz 1991, 1993;Schramke et al 1987;Tanner et al 1985). Mineral powder reactants, though, have much greater surface areas than rocks do, resulting in fast reaction rates.…”

Section: Discussionmentioning

confidence: 99%

“…Laboratory studies of reaction rates are generally performed with the use of mineral powders to approximate rock assemblages (e.g., Dachs and Metz 1988;Heinrich et al 1986Heinrich et al , 1989Kase and Metz 1980;Kridelbaugh 1973;Lüttge and Metz 1991;Schramke et al 1987;Tanner et al 1985). Those studies were successful in describing mechanisms and rates of reactions, but the large porosities and surface areas of powders in direct contact with an abundant fl uid phase differ considerably from low-permeability rocks (Lüttge and Metz 1993).…”

Section: Introductionmentioning

confidence: 98%

Experimental investigation of the breakdown of dolomite in rock cores at 100 MPa, 650-750 C

DeAngelis

Labotka

Cole

et al. 2007

American Mineralogist

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The kinetics of the breakdown reaction dolomite = periclase + calcite + CO 2 were investigated using cores of dolomitic marble. Two samples of Reed Dolomite from southwestern Nevada were cut into cylinders approximately 4 × 6 mm in size. The cores were sealed in gold capsules with isotopically enriched water (H 2 18 O or HD 18 O 0.5 16 O 0.5 ). The samples were heated in a cold-seal hydrothermal apparatus to 650-750 °C at 100 MPa for durations ranging from 2-59 days. The cores were then sectioned and examined by EPMA, XRD, and SIMS techniques. All experiments showed some amount of reaction regardless of duration or temperature. Reaction products occurred mainly along grain boundaries, fractures within grains, and along sample edges. Ion images and isotope-ratio analysis indicated that reaction products exchanged with infi ltrating fl uids. Reaction rates were calculated from measured extents of reaction, which were determined from automated EPMA modes. At 700 °C, we measured reaction rates ranging from 3.8 × 10 -14 to 2.3 × 10 -12 mol/mm 2 ·s. The extent of reaction is proportional to the square root of time, suggesting a diffusion-controlled process. A shrinking-core model for the dolomite breakdown reaction fi ts the grain-size data, suggesting that diffusion of H 2 O and CO 2 through the mantle of reaction products controlled the rate. Apparent activation energies for that diffusion are ~283 ± 32 kJ/mol for coarse-grained samples and ~333 ± 36 kJ/mol for fi ne-grained samples. Initial reaction occurred relatively fast near the surface of dolomite grains, but continued diffusion through the reaction products ultimately controlled the rate of dolomite breakdown.

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Mechanism and kinetics of the reaction: 1 dolomite + 2 quartz = 1 diopside + 2 CO2: a comparison of rock-sample and of powder experiments

Lüttge

Metz

1993

Contr. Mineral. and Petrol.

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Experimental investigation of the mechanism of the reaction: 1 tremolite+11 dolomite ? 8 forsterite+13 calcite+9 CO2+1H2O

Cited by 13 publications

References 28 publications

Effects of hydrostaticity on the structural stability of carbonates at lower mantle pressures: the case study of dolomite

Effects of hydrostaticity on the structural stability of carbonates at lower mantle pressures: the case study of dolomite

Experimental investigation of the breakdown of dolomite in rock cores at 100 MPa, 650-750 C

Mechanism and kinetics of the reaction: 1 dolomite + 2 quartz = 1 diopside + 2 CO2: a comparison of rock-sample and of powder experiments

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