The impact origin of the structure was confirmed in 1997 when poorly developed planar deformation features (PDFs) in quartz grains were found in drill-core samples obtained from the bottom of the structure by a mining company while searching for diamonds in the region.

Saarijärvi is the only currently accepted impact structure in the Fennoscandian Shield formed in Archean granitoid basement complex.

The structure's age has not been determined, but the oldest sediments from the drill-core are from the Ediacaran period, i.e. about 600 Ma (million years) old.

It is currently unclear whether or not at least some of the lowermost sediments are actually pre-impact in origin, while the upper part of the sequence may have been deposited after the impact.

The cross-section of the structure is somewhat asymmetric with a deeper and steeper southern side compared to the northern one, which suggests tectonic modification rather than an oblique impact.