Impaktyty struktury Popigaj, Syberia

The multi-ring Popigai structure formed in the crystalline rocks of sub-polar Siberia is the largest one in the Asia territory. The complexity of its structure, the weak erosion and numerous, deep geological drillings determine its uniqueness when compared to the rocks found in Chicxulub, Vredefort and Sudbury. Shocked rocks, mainly gneisses, have fluidal texture, heavily brecciated garnets and opaque minerals. The presence of high- and low-temperature impact melt breccia types called tagamites have been described from the crater. Breccias of suevite express variability from low-glassy types to highly porous structures similar to tuffisites. The part of melts or glasses with vesicles, crystallites and clasts can be interpreted as pseudotachylite. Mineral globules and corroded clasts can be found in impactites. Feldspars are transformed into maskelynite, and quartz into lechatelierite. Sometimes quartz shows the ballen structure and has nebulous contacts. Graphite, ilmenite, and pyrite are dispersed in tagamites. The secondary mineralization of zeolites occurred in vesicles.