Silicon self-diffusion in wadsleyite: Implications for rheology of the mantle transition zone and subducting plates

Details Silicon self-diffusion in wadsleyite: Implications for rheology of the mantle transition zone and subducting plates Silicon self-diffusion in wadsleyite: Implications for rheology of the mantle transition zone and subducting plates

Jul 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004georl..3113606s&link_type=abstract

Geophysical Research Letters, Volume 31, Issue 13, CiteID L13606

Physics

6

Mineral Physics: Creep And Deformation, Mineral Physics: Defects, Mineral Physics: High-Pressure Behavior, Physical Properties Of Rocks: Plasticity, Diffusion, And Creep, Tectonophysics: Rheology-Mantle

Scientific paper

Si self-diffusion rates in Mg2SiO4 polycrystalline wadsleyite were measured at 18 GPa and 1430-1630°C using an isotopic tracer (29Si) and secondary ion mass spectrometry. The volume diffusion coefficient (Dv) and grain-boundary diffusion coefficient (Dgb) were determined to be Dv = 3.44 × 10-11 [m2/s] exp (-299 [kJ/mol]/RT) and δDgb = 1.14 × 10-17 [m3/s] exp (-248 [kJ/mol]/RT), respectively. Si diffusion rates in wadsleyite are about 5 orders of magnitude slower than Mg-Fe interdiffusion rates at 1400°C. Assuming that Si is the slowest diffusing species in wadsleyite, the geophysical model of the viscosity in the mantle transition zone can be explained by diffusion creep in wadsleyite for a grain size of about 0.5-5 mm. Some portions in cold subducting slabs, where the grain size reduces to less than 1 μm after the olivine-spinel transformation, become weaker than the surrounding mantle.

Affiliated with

Also associated with

No associations

Rating

Silicon self-diffusion in wadsleyite: Implications for rheology of the mantle transition zone and subducting plates does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Silicon self-diffusion in wadsleyite: Implications for rheology of the mantle transition zone and subducting plates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silicon self-diffusion in wadsleyite: Implications for rheology of the mantle transition zone and subducting plates will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1010214