Static compressibility of magnesite to 20 GPa: Implications for MgCO3 in the lower mantle

S. A T Redfern; B. J. Wood; C. M B Henderson

doi:10.1029/93GL02507

Static compressibility of magnesite to 20 GPa

Implications for MgCO₃ in the lower mantle

S. A T Redfern^*, B. J. Wood, C. M B Henderson

^*Corresponding author for this work

Research output: Contribution to journal › Article

43 Citations (Scopus)

Abstract

The bulk modulus of MgCO₃ magnesite has been measured to 20 GPa at room temperature using X‐ray powder diffraction. Since the response to pressure is primarily compression of the MO₆ octahedron, magnesite is substantially less compressible than Ca‐carbonates of similar structure type. Using the Birch equation of state, with K_T′ of 4.0, we obtain K_T of 142 (±9) GPa at room temperature. The full Birch‐Murnaghan equation of state yields K_T of 151 (±7) GPa and K_T′ of 2.5. These results, together with other thermodynamic data, have been applied to calculate the stability of magnesite under lower mantle conditions. Assuming lower‐mantle saturation in (Mg,Fe)O, magnesite should be stable to temperatures well in excess of 6000 K at the core‐mantle boundary, i.e. at least up to the solidus of peridotitic or pyroxenitic compositions. This confirms that magnesite is a stable host for carbon in the mantle.

Original language	English
Pages (from-to)	2099-2102
Number of pages	4
Journal	Geophysical Research Letters
Volume	20
Issue number	19
DOIs	https://doi.org/10.1029/93GL02507
Publication status	Published - 1993

Access to Document

10.1029/93GL02507

Link to publication in Scopus

Fingerprint Dive into the research topics of 'Static compressibility of magnesite to 20 GPa: Implications for MgCO<sub>3</sub> in the lower mantle'. Together they form a unique fingerprint.

Cite this

Redfern, S. A. T., Wood, B. J., & Henderson, C. M. B. (1993). Static compressibility of magnesite to 20 GPa: Implications for MgCO₃ in the lower mantle. Geophysical Research Letters, 20(19), 2099-2102. https://doi.org/10.1029/93GL02507

@article{ba5f5dd873d3441b92cd194eb25b8557,

title = "Static compressibility of magnesite to 20 GPa: Implications for MgCO3 in the lower mantle",

abstract = "The bulk modulus of MgCO3 magnesite has been measured to 20 GPa at room temperature using X‐ray powder diffraction. Since the response to pressure is primarily compression of the MO6 octahedron, magnesite is substantially less compressible than Ca‐carbonates of similar structure type. Using the Birch equation of state, with KT′ of 4.0, we obtain KT of 142 (±9) GPa at room temperature. The full Birch‐Murnaghan equation of state yields KT of 151 (±7) GPa and KT′ of 2.5. These results, together with other thermodynamic data, have been applied to calculate the stability of magnesite under lower mantle conditions. Assuming lower‐mantle saturation in (Mg,Fe)O, magnesite should be stable to temperatures well in excess of 6000 K at the core‐mantle boundary, i.e. at least up to the solidus of peridotitic or pyroxenitic compositions. This confirms that magnesite is a stable host for carbon in the mantle.",

author = "Redfern, {S. A T} and Wood, {B. J.} and Henderson, {C. M B}",

year = "1993",

doi = "10.1029/93GL02507",

language = "English",

volume = "20",

pages = "2099--2102",

journal = "Geophysical Research Letters",

issn = "0094-8276",

publisher = "American Geophysical Union",

number = "19",

}

TY - JOUR

T1 - Static compressibility of magnesite to 20 GPa

T2 - Implications for MgCO3 in the lower mantle

AU - Redfern, S. A T

AU - Wood, B. J.

AU - Henderson, C. M B

PY - 1993

Y1 - 1993

N2 - The bulk modulus of MgCO3 magnesite has been measured to 20 GPa at room temperature using X‐ray powder diffraction. Since the response to pressure is primarily compression of the MO6 octahedron, magnesite is substantially less compressible than Ca‐carbonates of similar structure type. Using the Birch equation of state, with KT′ of 4.0, we obtain KT of 142 (±9) GPa at room temperature. The full Birch‐Murnaghan equation of state yields KT of 151 (±7) GPa and KT′ of 2.5. These results, together with other thermodynamic data, have been applied to calculate the stability of magnesite under lower mantle conditions. Assuming lower‐mantle saturation in (Mg,Fe)O, magnesite should be stable to temperatures well in excess of 6000 K at the core‐mantle boundary, i.e. at least up to the solidus of peridotitic or pyroxenitic compositions. This confirms that magnesite is a stable host for carbon in the mantle.

AB - The bulk modulus of MgCO3 magnesite has been measured to 20 GPa at room temperature using X‐ray powder diffraction. Since the response to pressure is primarily compression of the MO6 octahedron, magnesite is substantially less compressible than Ca‐carbonates of similar structure type. Using the Birch equation of state, with KT′ of 4.0, we obtain KT of 142 (±9) GPa at room temperature. The full Birch‐Murnaghan equation of state yields KT of 151 (±7) GPa and KT′ of 2.5. These results, together with other thermodynamic data, have been applied to calculate the stability of magnesite under lower mantle conditions. Assuming lower‐mantle saturation in (Mg,Fe)O, magnesite should be stable to temperatures well in excess of 6000 K at the core‐mantle boundary, i.e. at least up to the solidus of peridotitic or pyroxenitic compositions. This confirms that magnesite is a stable host for carbon in the mantle.

UR - http://www.scopus.com/inward/record.url?scp=0027847955&partnerID=8YFLogxK

U2 - 10.1029/93GL02507

DO - 10.1029/93GL02507

M3 - Article

VL - 20

SP - 2099

EP - 2102

JO - Geophysical Research Letters

JF - Geophysical Research Letters

SN - 0094-8276

IS - 19

ER -