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Swollen Kamacite lamellae |
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| Yarovoye, IIIAB Iron, fine octahedrite . |
| Lamellae in iron
meteorites are considered secondary structures. They form in space during the
slow cooling after primary crystallization of an asteroid's iron-nickel molten
metal core. This process occurs over millions of years, allowing the iron-nickel alloys (kamacite and taenite) to exsolve and create the distinctive Widmanstätten pattern. Swollen kamacite lamellae refer to thicker, more pronounced bands of kamacite. The term "swollen" indicates that the kamacite bands are more prominent and irregular-shaped than usual, see image, which can occur due to variations in the cooling rate or an increased presence of certain elements - phosphorus, sulfur, and carbon. These elements can affect the diffusion rates of nickel and iron, leading to variations in the size and morphology of the primary kamacite lamellae. |
| Later impact events causing shock metamorphism can produce an altered lamellae, usually a recrystallization of the metal. |
Figure 1. Scale bar 1 mm. |
| Yarovoye, IIIAB Iron, fine octahedrite. |
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