Arnarker

Arnarker is in the Samsstaðamúli crater area of southern Iceland. It is a notable Icelandic lava tube with extensive underground passages.

Arnarker formed when basaltic lava flowed and later drained from a tunnel beneath a hardened surface. This process leaves the tube-like cave structure typical of volcanic lava fields.

Its passages preserve evidence of how Icelandic basaltic lava moved underground. The cave is notable because its size and extent make it useful for understanding local volcanic processes.

No, Arnarker is a lava tube formed by volcanic basalt. That makes its origin different from limestone caves, which develop through the dissolution of soluble rock.