Craters Grabrok, in the extremely beautiful area surrounding Bifrost and the lava field are 3600-4000 years old.

Mt. Baula.  No tholoid mountains are found in Iceland.  This mountain is a shallow, alkaline laccolith, probably created by a sub-glacial eruption like Mt. Hlidarfjall on Lake Myvatn and Mts. Hagongur in the interior.

The Snaefell's Peninsula has relatively large alkaline areas, rhyolite and granofire intrusions.  Its eruptive areas, like those in the South, are the so-called Flank Zones.  Mt. Snaefell is a dormant, alkaline, andesite volcano.  This strato volcano erupted about 1760 and 3000 years ago.  These eruptions were highly explosive and diffusive.  Half the mountain collapsed.  It is likely, that a few minor eruptions, which explain the existence of the smaller craters around the volcano, took place later.

The Lysuskard System takes over east of the Snaefell volcano and depicts craters and rhyolite intrusions.

The Berserk Lava Field was created almost at the same time as the Grabrok craters and lava field, 3600-4000 years ago.

The Eldborg Crater was created 5000-8000 years ago in an effusive eruption.

Craters Raudamelskulur were created about 2600 years ago.

Craters Raudhals were created about 1100 years ago.