The Terny structure is an example of the highly denuded astrobleme, formed in crystalline target rocks of the Ukrainian Shield. Primarily, its impactites were discovered in two mines of iron ore, Pervomaysk and Annovsk, established in jaspilite and magnetite deposits. The Terny impactites are characterised by examples of various breccias, including a ferrugineous one and suevite, and melt rock (tagamite). Quartz of low birefringence, multidirectional PDFs in quartz, isotropic glassy quartz and glass globules evidence an impact influence on rocks. Clasts of melt/glassy quartz were partly brecciated or changed into clay minerals. Clasts of metamorphosed rocks in matrix of breccia are angular or rounded. Their sharp or diffuse contacts with matrix prove the influence of a unidirectional factor on the formation of breccia.
The complex Ilyinets crater is an example of the small impact structure formed in crystalline target rocks of the Ukrainian Shield. Its impactites are characterised by examples of metamorphosed gneisses, granites, fine-grained polymict breccia and suevites. In the breccia and suevite matrix, fluidal clasts present their earlier brecciation. Lobate contacts between quartz grains show recrystallisation by grain-boundary migration. Shock structures, PFs, PDFs and “ballen quartz” are not very frequent. The monomict suevite breccia was determined among impactites.
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