Thermal diffusivity of MORB-composition rocks to 15 GPa: implications for triggering of deep seismicity

David P. Dobson; Simon A. Hunt; Richard McCormack; Oliver T. Lord; Donald J. Weidner; Li Li; Andrew M. Walker

doi:10.1080/08957959.2010.516827

Thermal diffusivity of MORB-composition rocks to 15 GPa: implications for triggering of deep seismicity

David P. Dobson, Simon A. Hunt, Richard McCormack, Oliver T. Lord, Donald J. Weidner, Li Li, Andrew M. Walker

Materials Engineering

Research output: Contribution to journal › Article › peer-review

Abstract

We have measured the thermal diffusivity of eclogite and majorite with a model MORB composition at pressures of 3 and 15GPa, respectively. Both phase assemblages show inverse dependences of their thermal diffusivities on temperature: D eclogite =9(10)×10 -10 +7(1) ×10 -4 /T(K)m 2 /s and D majorite =6.2(5) ×10 -7 +3.0(5)×10 -4 /T(K)m 2 /s. The values for majorite are in good agreement with previous measurements for other garnets and are considerably lower than thermal diffusivities of wadsleyite and ringwoodite, which are the main components of the mantle transition zone. We discuss the implications of the low thermal conductivity of subducted oceanic crust in the transition zone for the triggering of deep seismicity. textcopyright 2010 Taylor Francis.

Original language	English
Pages (from-to)	406-414
Number of pages	9
Journal	High Pressure Research
Volume	30
Issue number	3
DOIs	https://doi.org/10.1080/08957959.2010.516827
Publication status	Published - 1 Sept 2010

Keywords

MORB
deep earthquakes
high pressure
majorite
thermal diffusion

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10.1080/08957959.2010.516827

http://www.tandfonline.com/doi/abs/10.1080/08957959.2010.516827

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title = "Thermal diffusivity of MORB-composition rocks to 15 GPa: implications for triggering of deep seismicity",

abstract = "We have measured the thermal diffusivity of eclogite and majorite with a model MORB composition at pressures of 3 and 15GPa, respectively. Both phase assemblages show inverse dependences of their thermal diffusivities on temperature: D eclogite =9(10)×10 -10 +7(1) ×10 -4 /T(K)m 2 /s and D majorite =6.2(5) ×10 -7 +3.0(5)×10 -4 /T(K)m 2 /s. The values for majorite are in good agreement with previous measurements for other garnets and are considerably lower than thermal diffusivities of wadsleyite and ringwoodite, which are the main components of the mantle transition zone. We discuss the implications of the low thermal conductivity of subducted oceanic crust in the transition zone for the triggering of deep seismicity. textcopyright 2010 Taylor Francis.",

keywords = "MORB, deep earthquakes, high pressure, majorite, thermal diffusion",

author = "Dobson, {David P.} and Hunt, {Simon A.} and Richard McCormack and Lord, {Oliver T.} and Weidner, {Donald J.} and Li Li and Walker, {Andrew M.}",

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T1 - Thermal diffusivity of MORB-composition rocks to 15 GPa

T2 - implications for triggering of deep seismicity

AU - Dobson, David P.

AU - Hunt, Simon A.

AU - McCormack, Richard

AU - Lord, Oliver T.

AU - Weidner, Donald J.

AU - Li, Li

AU - Walker, Andrew M.

PY - 2010/9/1

Y1 - 2010/9/1

N2 - We have measured the thermal diffusivity of eclogite and majorite with a model MORB composition at pressures of 3 and 15GPa, respectively. Both phase assemblages show inverse dependences of their thermal diffusivities on temperature: D eclogite =9(10)×10 -10 +7(1) ×10 -4 /T(K)m 2 /s and D majorite =6.2(5) ×10 -7 +3.0(5)×10 -4 /T(K)m 2 /s. The values for majorite are in good agreement with previous measurements for other garnets and are considerably lower than thermal diffusivities of wadsleyite and ringwoodite, which are the main components of the mantle transition zone. We discuss the implications of the low thermal conductivity of subducted oceanic crust in the transition zone for the triggering of deep seismicity. textcopyright 2010 Taylor Francis.

AB - We have measured the thermal diffusivity of eclogite and majorite with a model MORB composition at pressures of 3 and 15GPa, respectively. Both phase assemblages show inverse dependences of their thermal diffusivities on temperature: D eclogite =9(10)×10 -10 +7(1) ×10 -4 /T(K)m 2 /s and D majorite =6.2(5) ×10 -7 +3.0(5)×10 -4 /T(K)m 2 /s. The values for majorite are in good agreement with previous measurements for other garnets and are considerably lower than thermal diffusivities of wadsleyite and ringwoodite, which are the main components of the mantle transition zone. We discuss the implications of the low thermal conductivity of subducted oceanic crust in the transition zone for the triggering of deep seismicity. textcopyright 2010 Taylor Francis.

KW - MORB

KW - deep earthquakes

KW - high pressure

KW - majorite

KW - thermal diffusion

U2 - 10.1080/08957959.2010.516827

DO - 10.1080/08957959.2010.516827

M3 - Article

SN - 0895-7959

VL - 30

SP - 406

EP - 414

JO - High Pressure Research

JF - High Pressure Research

IS - 3

ER -

Thermal diffusivity of MORB-composition rocks to 15 GPa: implications for triggering of deep seismicity

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Keywords

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