Protoanthophyllite from three metamorphosed serpentinites

Hiromi Konishi, I. Dódony, Peter R. Buseck

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

This is the first report of a natural Mg-rich protoanthophyllite. It is common in metamorphosed serpentinites from three Japanese ultramafic complexes, and some crystals contain anthophyllite (Pnma) lamellae. The Mg/(Mg + Fe) ratios of the Hayachine, Tari-Misaka, and Takase protoanthophyllites are 0.90,0.92, and 0.91, respectively. The samples have identical optical properties: X = a, Y = b. Z = c, and 2Vx = 64 ± 5°. Their space group is Pnmn (or Pn2n), as revealed by systematic extinctions in selected-area electron-diffraction patterns. The protoanthophyllite and anthophyllite have similar compositions and orthorhombic symmetry. They are difficult to distinguish using optical, microanalytical, and powder X-ray diffraction measurements. This problem raises the possibility that some of the published data on geological and synthetic anthophyllite samples may be of misidentified materials, potentially leading to errors in the published stability relations of anthophyllite. We provide a method to identify protoanthophyllite and differentiate it from its polymorphs using selected-area electron diffraction and high-resolution transmission electron microscopy methods.

Original languageEnglish
Pages (from-to)1096-1103
Number of pages8
JournalAmerican Mineralogist
Volume87
Issue number8-9
Publication statusPublished - Aug 2002

Fingerprint

anthophyllite
electron diffraction
lamella
Electron diffraction
diffraction
extinction
diffraction patterns
optical properties
electron
transmission electron microscopy
high resolution
symmetry
High resolution transmission electron microscopy
Polymorphism
optical property
X ray powder diffraction
Diffraction patterns
crystals
x rays
Optical properties

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

Konishi, H., Dódony, I., & Buseck, P. R. (2002). Protoanthophyllite from three metamorphosed serpentinites. American Mineralogist, 87(8-9), 1096-1103.

Protoanthophyllite from three metamorphosed serpentinites. / Konishi, Hiromi; Dódony, I.; Buseck, Peter R.

In: American Mineralogist, Vol. 87, No. 8-9, 08.2002, p. 1096-1103.

Research output: Contribution to journalArticle

Konishi, H, Dódony, I & Buseck, PR 2002, 'Protoanthophyllite from three metamorphosed serpentinites', American Mineralogist, vol. 87, no. 8-9, pp. 1096-1103.
Konishi, Hiromi ; Dódony, I. ; Buseck, Peter R. / Protoanthophyllite from three metamorphosed serpentinites. In: American Mineralogist. 2002 ; Vol. 87, No. 8-9. pp. 1096-1103.
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