TY - JOUR
T1 - Three-dimensional study by synchrotron radiation computed tomography of melt distribution in samples doped to enhance contrast
AU - Ikeda, Susumu
AU - Nakano, Tsukasa
AU - Tsuchiyama, Akira
AU - Uesugi, Kentaro
AU - Nakashima, Yoshito
AU - Nakamura, Koichi
AU - Yoshida, Hideto
AU - Suzuki, Yoshio
N1 - Funding Information:
The synchrotron radiation experiments were performed at SPring-8 with the approval and support by the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No. 2002A0354-NLM-np). Useful discussions with M. Nakamura (Tohoku University) are acknowledged. We thank H. Nagahara, A. Yasuda and M. Hamada (The University of Tokyo) for use of HIP in preparing partially molten specimens. We are also grateful to two reviewers (B. O. Mysen and an anonymous reviewer) and Editorial Board Member Ed Grew for helpful and constructive comments which improved the manuscript. This research was supported by the Research Fellowships of the Japan Society for the Promotion of Science (JSPS) for Young Scientists (to S.I.), Grant-in-Aid for Scientific Research (00J08525) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, and Global COE Program "Global Education and Research Center for Earth and Planetary Dynamics" at Tohoku University (Leader: E. Ohtani) promoted by MEXT, Japan.
Publisher Copyright:
© 2016.
PY - 2017/10
Y1 - 2017/10
N2 - The three-dimensional (3-D) distribution of melt in partially molten synthetic samples compositionally corresponding todiopside (90 wt%) - anorthite (10 wt%) and doped with PbO, WO3, MoO3, or Cs2O to enhance contrast was studied by X-ray computed tomography (CT) with synchrotron radiation at SPring-8. The heavy elements were strongly concentrated in the melt and contributed to an increase of the X-ray linear attenuation coefficient (LAC) of the melt. It was found that PbO is compatible with silicate melt (> 20 wt% in solution) and incompatible with diopside crystals. Other oxides WO3 (∼10 wt%), MoO3 (∼5 wt%), and Cs2O (< 5 wt%) are also soluble only in the melt.Such doping is useful not only for LAC control in X-ray CT measurement, but also for systematic control of the structure (wetting properties, distribution and connectivity) of partial melt. This technique gives basic information for discussion of 3-D distribution of partial melt having different wetting properties. Since PbO was the most effective in visualization of the diopside - anorthite partially molten system, the CT images of the PbO-bearing sample were used for further 3-D investigation of distribution. A distribution of dihedral angles at solid-melt-solid triple junctions ranging from 22° to 55° was observed with the 3-D data. This range in angle distribution was probably caused by anisotropy of crystals and the result supports the argument that there is some limitation in a theoretical framework 53 of stereology which estimates the 3-D structure based on 2-D observation. Investigators have begun to apply X-ray CT to the study of 3-D distribution of partial melt in rocks using synchrotron radiation facilities. Our study on the effect of doping is one approach for developing a technique to investigate 3-D melt distribution.
AB - The three-dimensional (3-D) distribution of melt in partially molten synthetic samples compositionally corresponding todiopside (90 wt%) - anorthite (10 wt%) and doped with PbO, WO3, MoO3, or Cs2O to enhance contrast was studied by X-ray computed tomography (CT) with synchrotron radiation at SPring-8. The heavy elements were strongly concentrated in the melt and contributed to an increase of the X-ray linear attenuation coefficient (LAC) of the melt. It was found that PbO is compatible with silicate melt (> 20 wt% in solution) and incompatible with diopside crystals. Other oxides WO3 (∼10 wt%), MoO3 (∼5 wt%), and Cs2O (< 5 wt%) are also soluble only in the melt.Such doping is useful not only for LAC control in X-ray CT measurement, but also for systematic control of the structure (wetting properties, distribution and connectivity) of partial melt. This technique gives basic information for discussion of 3-D distribution of partial melt having different wetting properties. Since PbO was the most effective in visualization of the diopside - anorthite partially molten system, the CT images of the PbO-bearing sample were used for further 3-D investigation of distribution. A distribution of dihedral angles at solid-melt-solid triple junctions ranging from 22° to 55° was observed with the 3-D data. This range in angle distribution was probably caused by anisotropy of crystals and the result supports the argument that there is some limitation in a theoretical framework 53 of stereology which estimates the 3-D structure based on 2-D observation. Investigators have begun to apply X-ray CT to the study of 3-D distribution of partial melt in rocks using synchrotron radiation facilities. Our study on the effect of doping is one approach for developing a technique to investigate 3-D melt distribution.
KW - 3-D observation
KW - X-ray computed tomography
KW - contrast enhancement
KW - dihedral angle
KW - doping
KW - partial melting
KW - synchrotron radiation
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U2 - 10.1180/minmag.2016.080.163
DO - 10.1180/minmag.2016.080.163
M3 - Article
AN - SCOPUS:85031130264
VL - 81
SP - 1203
EP - 1222
JO - Mineralogical Magazine
JF - Mineralogical Magazine
SN - 0026-461X
IS - 5
ER -