CIDER experience - PowerPoint PPT Presentation

1 / 10
About This Presentation
Title:

CIDER experience

Description:

Changed thesis to 'Geophysics and Geochemistry of Iron in the Core-Mantle Boundary and Core' ... differences, analogous to multiple pyroxene structures in the crust ... – PowerPoint PPT presentation

Number of Views:18
Avg rating:3.0/5.0
Slides: 11
Provided by: wendy127
Category:

less

Transcript and Presenter's Notes

Title: CIDER experience


1
CIDER experience
  • Attended 2004 lecture and tutorial session
  • Very useful for my education
  • Post-perovskite (ppv) fever
  • Changed thesis to Geophysics and Geochemistry of
    Iron in the Core-Mantle Boundary and Core
  • More recently have been using on-line lectures as
    a resource for class I co-taught this winter on
    Earth Structure
  • Still working on ppv

2
Implications of the Fe-rich ppv at CMB
  • Possible explanation for ULVZ
  • Multiple ppv structures due to compositional
    differences, analogous to multiple pyroxene
    structures in the crust
  • Different Fe/Mg partitioning from Fe-poor ppv

3
Implications of the Fe-rich ppv at CMB
  • Possible explanation for ULVZ
  • Multiple ppv structures due to compositional
    differences, analogous to multiple pyroxene
    structures in the crust
  • Different Fe/Mg partitioning from Fe-poor ppv

4
Fe in ULVZ
  • Fe-rich ppv has low enough Vs to explain the
    depression of velocity in ULVZ

5
Implications of the Fe-rich ppv at CMB
  • Possible explanation for ULVZ
  • Multiple ppv structures due to compositional
    differences, analogous to multiple pyroxene
    structures in the crust
  • Different Fe/Mg partitioning from Fe-poor ppv

6
Structure of Fe-rich ppv differs from Fe-poor ppv
Fe0.4Mg0.6SiO3
Pmma
Cmcm
Cmcm fits the data but not as well as Pmma
7
Two different Fe sites in Fe-rich ppv
  • Pmma
  • M1 Fe0.25 Mg0.75, (30 of Fe)
  • M2 Fe0.55 Mg0.45, (70 of Fe)

8
Intermediate spin?
  • SMS shows two predominant sites, consistent with
    the XRD results?

Lin et al, Nature Geoscience 2008
9
Implications of the Fe-rich ppv at CMB
  • Possible explanation for ULVZ
  • Multiple ppv structures due to compositional
    differences, analogous to multiple pyroxene
    structures in the crust
  • Different Fe/Mg partitioning from Fe-poor ppv

10
Fe-Mg partitioning
From Auzende et al, EPSL 2008
  • Reaction between ppv, mw, and Fe. Core
    undersaturated in Si and O? Iron-depletion at
    base of mantle? Knittle and Jeanloz, Science
    1991, Takafuji et al, GRL 2005, Sakai et al,
    GRL 2006, Asahara et al, EPSL 2007, Ozawa et al,
    GRL 2008
  • Does partitioning depend on Fe content?
Write a Comment
User Comments (0)
About PowerShow.com