Occurrence and characteristics of the Miocene sandstones from the area of Giełczew Elevation and Chełm Hills (Lublin Region)

Abstract

The studied sandstones from the Giełczew Elevation and the Chełm Hills become an important unit that ended the Neogene deposition in the Lublin Region. They outcrop in the upper part
of Sarmatian sandstones building the butte elevations up 100 m high. These sandstones are porous, with an undefined oligomictic rock skeleton. They are mainly structureless but some sedimentary structures (e.g. cross-bedding, convolute stratification), are also observed. Grain skeleton consists
in general of poorly rounded quartz grains and several percent of feldspars. Quartz is represented by triangle-shaped and poorly rounded crystals, with visible mineral corrosion, which indicates a
short transport and rounded grains (extraclasts with wavy light dimming), as well as by scarcely redeposited well-rounded quartzite clasts. This skeleton was cemented with a basal-contact matrix some rock voids, microfossils and ooids, replacing the primary carbonate bioclasts. Microsedimentary and paleontological analyses documented that the studied deposits originated probably in the shallow basins (e.g. ooids presented in some samples) with varied salinity and a significant input of
riverine material.