State of Fe atoms in minerals of the Saratov chondrite affected by spherical impact waves

The structural and valent state of iron atoms was studied by Mossbauer spec troscopy on Fe-57 nuclei in two intact samples of the Saratov chondrite (L4 , fall) affected by spherically convergent detonation waves. In accordance with the geometry of detonation wave loading, an increase in peak pressure was produced from the sphere's surface to its center, where ultrahigh impac t loading was reached. The Mossbauer spectra indicate the following iron-be aring phases: olivine, pyroxene, iron sulfides, kamacite, and spinel with m agnetically ordered and paramagnetic structures. Phase transformations acco mpanied by oxidation-reduction processes were observed from the surface to the center of the compressed meteorite samples. The reduction of iron to me tallic iron occurs From the zone of plastic deformation to the zone of part ial melting, whereas the fraction of Fe2+ ions increases from the zone of p artial melting to the zone of melting. The amount of impurities and local i nhomogeneities of iron atoms in iron-bearing minerals increase with an incr easing degree of impact metamorphism. In comparison to the monolithic sampl e, the sample prepared from the matrix material showed displacement of the impact zones toward the sample surface, a change in thickness, and an incre ase in the degree of local distortions in mineral structures in each zone.