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Drusy vugs in an iron meteorite |
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| Albion, IVA, iron, fine octahedrite. |
| Drusy vugs in an
iron meteorite are small cavities inside the iron. They are relatively common
in terrestrial geology, occurring in igneous, sedimentary, and metamorphic
rocks. They are irregular in shape, mostly forming from cracks and
fissures. In iron meteorites, vugs are rarely seen. What sets Albion apart from others is that it is the only known iron meteorite with vugs lined in its interior with masses of spheroidal-shaped drusy mineralogy. Are the vugs primary or secondary? The Albion iron was not part of a core; it had cracks, voids, and perhaps imperfectly sealed grain boundaries that allowed the passage of hot fluid or a gaseous vapor. These would have mobilized troilite, fractionated nickel, and ultimately deposited drusy spheroids on the interior walls of vugs.This is a more likely scenario than shock-melting. For a shock scenario, one would expect shock effects in the kamacite/taenite lamellae of the surrounding Widmanstatten structures. Evidence of shock would make it plausible to argue that the vugs in Albion are secondary. This evidence is not seen (1) (2). The surrounding kamacite and taenite lamellae do not display shock effects or damage. Lacking further study, the vugs in the Albion iron are deemed of primary origin. 1 Marvin U.B., Petaev M.I., Kempton R. W. (1996) LPS XXV11, 821 2 Kempton R. W., (1995) Meteorite!, Nov. Iss. |
Figure 1. Scale bar 2.6 mm. |
| Albion, IVA, iron, fine octahedrite. |
| Vug lined with drusy mineralogy. |
Figure 1. Scale bar 1.5 mm. |
| Albion, IVA, iron, fine octahedrite. |
| Vug interior. Daubreelite occures in blocky, euhedral grains in the spheroids. A new phosphide mineral occuring in rounded euhedral to subhedral grains was also found in the spheroids. (1). |
Figure 3. Scale bar 2.6 mm. |
| Albion, IVA, iron, fine octahedrite. |
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