Kumdykolite, a high-temperature feldspar from an enstatite chondrite

Péter Németh, Stephen W. Lehner, Michail I. Petaev, P R Buseck

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8 Scopus citations

Abstract

We report the first occurrence of kumdykolite in a meteorite (Sahara 97072, EH3). This orthorhombic form of albite occurs in the core of a concentrically zoned metal-sulfide nodule. In contrast to the terrestrial kumdykolite, the meteoritic sample has a domain structure that is consistent with either orthorhombic (Pmnn) or monoclinic (P21) space groups. The two symmetries are indicated by the presence or lack, respectively, of h + k = 2n + 1 reflections in [001] selected-area electron diffraction patterns, effects that likely result from different Si-Al ordering. Pmnn kumdykolite has only one tetrahedral site for Si and Al, whereas P21 kumdykolite would have three tetrahedral sites for Si and one for Al. We propose that kumdykolite formed above 1300 K and cooled rapidly enough to preserve its unique structure. Apparently, the cooling rate varied on the scale of nanometers allowing the local development of Si-Al ordering.

Original languageEnglish (US)
Pages (from-to)1070-1073
Number of pages4
JournalAmerican Mineralogist
Volume98
Issue number5-6
DOIs
StatePublished - May 1 2013

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Keywords

  • Albite polymorph
  • Domain structure
  • Enstatite chondrite
  • Kumdykolite
  • Si-Al ordering

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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