Reprinted from the proceedings of the Meteoritical
Society, July 1996
DRUSY VUGS IN THE ALBION IRON METEORITE: MINERALOGY AND
TEXTURES. U.B. Marvin1, M.I. Petaev1, and R.
Kempton2, 1Harvard-Smithsonian Center for Astrophysics,
Cambridge, MA 02138, USA, 2New England Meteoritical Services, Mendon
MA 01756, USA.
Albion (name submitted to the Nomenclature Committee of the
Meteoritical Society), a IVA fine octahedrite, is unique in having vugs
scattered throughout the otherwise orderly Widmanstätten structure, The
most prominent vugs are open cavities, up to ~5 x 9 mm, partially filled with
drusy spheroidal masses. The final growth phase was the deposition of a thin
rim chiefly of kamacite on all exposed surfaces. Such vugs are surrounded by
thin zones, (less than or equal to) 2 mm wide, of granulated kamacite. A second
type of vug lining, observed by Buchwald  consists of masses of cubic Fe
crystals with (less than or equal to) 0.5 wt% Ni. Still other vugs occur as
narrow voids, (less than or equal) to 2 mm long, and as minute vacuoles a few
micrometers across, along the kamacite-taenite grain boundaries of the
The spheroidal masses consist mainly of irregular kamacite
grains. 1-35 (micrometers) across, containing 2-3.5 wt% Ni, plus a few rounded
segregations of Ni-rich tetrataenite with 55.6 wt% Ni. Enmeshed in both metals
are thin, branching films of troilite that appears to have invaded and corroded
them. Scattered throughout the spheroids are blocky, euhedral grains of
daubreelite (FeCr2S4), and scarcer ones of euhedral
The Ni content of kamacites rises steadily from 2-3.5 wt% in
the spheroids to ~5.3 wt% in the granulated nectar zone to 7.1 wt% Ni in the
Widmanstätten patterns. Along the same traverses, the content of Ni in the
tetrataenite grains drops precipitously from ~55 wt% Ni in the spheroids and
granulated zone to an average of 33.7 wt% Ni in the taenite of the main mass.
We have observed no evidence of shock metamorphism in the meteorite. Clearly,
the Albion iron has been subject to the passage of reactive fluid phases during
one or more episodes of its history. Possibilities, will be discussed in our
companion paper .
References-. [I] Buchwald V.F. (1991) Meteoriter,
226, Petaev M.I. and Marvin U. B. this volume.
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