Miller Butte 03002: a new rare iron meteorite (IID) from Antarctica
European Journal of Mineralogy 18,6 (2006) 727-738;
The Miller Butte (MIB) 03002 iron meteorite was found during the XIX (2003-2004) Antarctic campaign of the Italian Programma Nazionale delle Ricerche in Antartide (PNRA) in northern Victoria Land (Antarctica). MIB 03002 is classified as a medium octahedrite belonging to the rare IID chemical group, and it is the first IID iron among the 30,000 specimens so far returned from Antarctica. The bulk chemistry of this meteorite indicates that it represents an intermediate member of the differentiation series of IID irons. Polygonal kamacite, shear planes in the Widmanst5tten structure and relies of cross-hatched E-structure indicate that MIB 03002 experienced important shock metamorphism (T >= 700 degrees C and P >= 13 GPa) and post-shock annealing, after primary cooling. With a terrestrial age of similar to 610 ka, MIB 03002 is the oldest meteorite fall in northern Victoria Land so far, and the oldest Antarctic iron found on blue ice. Possible relationships between the old terrestrial age of MIB 03002 and the regional glacial dynamics of the East Antarctic Ice Sheet in northern Victoria Land are also discussed.
iron meteorites;; terrestrial age;; cosmogenic nuclides;; Antarctica;; northern Victoria Land;; Miller Butte;; Mineralogy
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