IVA structural type iron meteorite from Kaposfüred (Kaposvár) with heterogeneous structure and composition

Abstract

main element composition in the different parts of the meteorite: Fe = 86.84–90.00%, Ni = 7.21–7.94%, Co = 0.335–
0.420%, Si = 0.20–0.90%, C > 1%. Beside the main constituents kamacite and taenite, it contains some Si-metal,
daubréelite, and graphite as well.
Based on the width of kamacite plates that varies between 0.1 and 0.65 mm, and considering the Ni, Co and Ir, Pt,
(Ga), Cr (etc.) concentrations, it can preliminarily be classified as a IVA structural type octahedrite (in which the plate
widths varies between 0.25 and 0.45 mm). On the etched surface the kamacite displays square-like internal structures
revealing a fine internal morphology. The Ni-content in kamacite varies between 4.27 and 7.10% (average 6.60%), and in
taenite 27 to 45% (average 34.2%).
The morphology of plessite is highly varied with irregular, elongated and rounded grains of different size. A poorly
developed Widmanstätten-like structure is discernable in some parts of the fine-grained plessite.
Multiple partial melting and re-crystallization events have proceeded in the different parts of the meteorite. The most
intense melting — that produced the taenite bands among others — has most probably taken place in the atmosphere.
Silicon is found partly in the kamacite, but predominantly is a minor constituent in the meteorite with high-pressure
body-centered cubic crystal structure.
The unevenly distributed carbon is exclusively represented by graphite. Its varied morphology and appearance may
point to different formation circumstances.