An expedition team of the University of Georgia discovered archaeological layers of prehistoric and historical times on a pyroclastic flow (geological formation) in Bolnisi, called the Kazreti Ortvala Cave.
The layers are rich in materials of the corresponding period, including fragments characteristic of ancient cultures: awls, lamellae, nuclei, as well as epigraphic, paleographic and architectural monuments of the Middle Ages.
A pyroduct, or lava tube, is a geomorphological formation created when the surface of a lava flow cools while the still-molten interior continues to drain outward.
