Donets aulakogene.
Gas field. Reef top in 3000 m. Asymmetric. N slope dipping 1-1.5°, S slope dipping 5-10°.
Encrusting microbes and algae as main reef builders. Girvanella, Tubiphytes, bryozoans (Fenestellidae).
Rare corals (Lithostrotion).
220-240 m thickness.
