Obukhov Formation
Geologic formation
From Wikipedia, the free encyclopedia
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.[2]
| 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 | |
Rovno amber is found in this formation,[3] and 90% of amber collected from the Obukhov Formation is extracted illegally and the trade is controlled by armed organised crime groups, although the Ukrainian government has begun to oversee excavations since 1993.[3]
Geological context
The Late Eocene Rovno amber is hosted in the Obukhov Formation, and it underlies the Early Oligocene Mezhigorje Formation.[4][3] The formation is found along the northwestern margin of the Ukrainian Crystalline Shield[1] exposed in the Rivne region of Ukraine and across the border near Rechitsa in the Gomel Region of Belarus.[5] The granite basement rock was overlain by sandy to clayey deposits that were host to alluvial amber.[3]
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.[6]
