At Kulagjógv, on the shoreline outside Froðba, a very beautiful and interesting geological phenomenon of basalt columns can be seen, with the columns oriented in various directions. The column fan within the gorge itself is particularly striking and may resemble dancing women.

Basalt columns originate from the cooling of basalt after it initially solidified, already when the temperature had dropped to around 1,000°C. Well-defined columns form especially when basalt cools relatively quickly, for example if the ground beneath a newly formed basalt flow is wet. The columns develop perpendicular to the direction of cooling, so if the cooling occurs from a flat surface, the columns become regularly vertical. If, however, the surface is uneven or cooling occurs from multiple directions, the shape and orientation of the columns will vary accordingly.

When water comes into contact with molten rock at temperatures above 1,000°C, it boils instantly and may explode into the melt. The magma is then shattered and can solidify into larger and smaller fragments. The smallest basalt fragments form (basalt) glass, while larger basalt blocks solidify and develop irregular columns oriented in different directions.

A single basalt flow originating from such a melt can therefore, in some places, display smooth and regular columns, while elsewhere it may be fragmented or show irregular columns with varying patterns.

Source: Jarðfeingi