Three-dimensional study by synchrotron radiation computed tomography of melt distribution in samples doped to enhance contrast

Susumu Ikeda, Tsukasa Nakano, Akira Tsuchiyama, Kentaro Uesugi, Yoshito Nakashima, Koichi Nakamura, Hideto Yoshida, Yoshio Suzuki

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1203-1222
Number of pages20
JournalMineralogical Magazine
Volume81
Issue number5
DOIs
Publication statusPublished - 2017 Oct

Keywords

  • 3-D observation
  • X-ray computed tomography
  • contrast enhancement
  • dihedral angle
  • doping
  • partial melting
  • synchrotron radiation

ASJC Scopus subject areas

  • Geochemistry and Petrology

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