Obukhov Formation | |
---|---|
Stratigraphic range: | |
Type | Geological formation |
Underlies | Mezhigorje Formation |
Overlies | Early Eocene Basement |
Thickness | 2–7 m (6.6–23.0 ft) |
Lithology | |
Other | Sand, Clay, Amber, Glauconite, Quartz |
Location | |
Location | Ukrainian Crystalline Shield |
Region |
The Obukhov Formation is a geologic formation in Belarus and Ukraine that dates to the Late Eocene; [1] the Obukhov Formation is equivalent to the Prussian Formation of Russia.
Rovno amber is found in this formation, [2] and 90% of amber collected from the Obukhov Formation is extracted illegally and the trade is controlled by armed organised crime groups. [2]
The Late Eocene Rovno amber is hosted in the Obukhov Formation, and it underlies the Early Oligocene Mezhigorje Formation. [3] [2] The formation is found along the northwestern margin of the Ukrainian Crystalline Shield [1] exposed in the Rivne region of the Ukraine and across the border near Rechitsa in the Gomel Region of Belarus. [4] The granite basement rock was overlain by sandy to clayey deposits that were host to alluvial amber. [2]
The two formations total between 2–7 m (6.6–23.0 ft) in thickness, both containing interbeds or mixtures of brown coals and carbonized vegetation. Both formations are sandy to clayey in texture, with the Obukhov Formation having more clayey glauconite- quartz plus sandy loess. [5]