In the early 1990s we observed and documented a NW-SE-trending clastic dike of sandy and muddy composition in Piusa quarry.
In 1990 a clastic dike was discovered at two sites of the southern wall of Piusa quarry (Fig.
Clastic dike 1 as the most representative structure (Figs.
Clastic dike 2 composed of sandy material is exposed in the uppermost 1.
Clastic dike 3 is exposed in the northern part of the NE wall of the quarry (F3; Fig.
Clastic dike 4 was found in the northwestern wall of the quarry.
In the eastern wall of the quarry only a single clastic dike was found.
The grain size distribution of both the dike and surrounding sandstone, matrix of the clastic dike and disintegrated clasts separated from the dike sandstone, and the content of clasts in dikes were studied (Tables 1-3).
Host of the clastic dike is weakly cemented except 1 m between samples Pi4 and Pi5 (Fig.
Clastic dike F4 is composed of relatively strongly cemented very fine sandstone, containing abundant angular clasts of variegated clayey silt with chaotic orientation.
As a whole, mineralogical and chemical data indicate that during the formation of the clastic dike and its subsequent history the authigenic mineralization process was negligible, except its enrichment with goethite.