Usually, we mention the large volcanic rift zones extending over central Iceland. But the small volcanic zones deserve attention as well. According to this model, they have one thing in common, that is they extend over a pair of convection rolls. Here, the zones and belts are marked centrally with a black line.
Grímsey Oblique Rift Zone is least known and hardly mentioned in overview material about the geology of Iceland. It connects the North Volcanic Zone with the Kolbeinsey Ridge. It has a similar function as Reykjanes Oblique Rift Zone, providing a connection with the Reykjanes Ridge. Apart from those two systems, there are three other marginal systems. First is Snaefellsnes Volcanic Belt, found in the West of Iceland and it seems to be hard to explain why it exists at all. In the East, Öraefajökull Volcanic Belt is also hard to explain, although it is usually said that it represents a new development as volcanic activity gradually moves eastwards. Finally, the South Iceland Volcanic Belt is not always regarded as an independent area, as it connects directly with the East Volcanic Zone.
All those zones and belts should be analyzed according to the effect of the relevant pair of convection rolls and how coupling between layers will affect their development. One more volcanic zone could be mentioned in this context, that of Hofsjökull. It is small and behaves in a different way than the West, East and North Volcanic Zones.