The Position of Ægir Ridge compared with Iceland and Norway

The Icelandic Plateau has a distinct elliptical shape, and thereby with a central point. This central point can be linked with continuations of Reykjanes Ridge and Kolbeinsey Ridge. Comparing that with the Ægir Ridge, another link is found, because there are exactly 15° between them along the relevant latitude (around 65.5°N). The Norwegian coast is found 15° along that latitude to the east.

Ægir Ridge https://en.wikipedia.org/wiki/Aegir_Ridge did shape most of the sea bottom between Iceland and Norway, until it was functionally replaced by the Kolbeinsey Ridge.

Iceland Plateau – Aegir Ridge – Norway

The fact that the exact center is at the eastern edge of Ægir Ridge can even tell a story for those exploring these features in the future. It shows that the ridge was shaped by the pulling effects between the North American Plate and the local small scale convection roll having opposing rotation, in the same way as the Kolbeinsey Ridge today, as well as the main volcanic zones of Iceland.


The Path of Jökulsá á Fjöllum River in Iceland

A large river of North Iceland shows resemblance with the forces underneath. It finds its way directly to the north by swaying to the polygons east of the central axis of the North Volcanic Zone. The small polygons there are under pressure from the central polygons of the volcanic zone, thereby breaking up diagonally from north to south, providing tectonic lines for the river to follow.

Jökulsá á Fjöllum River.

Three polygons are marked on the map, namely those with inner tectonic structure for the river to flow afert. The first is still affected by the East Volcanic Zone, with tensional forces leading the river to the NE. At the boundary of the next polygon, the river is already east of the central axis, and the polygon must therefore be subject to some pressure and rotation, breaking it diagonally NS. The river flows to the 2nd turn where it starts following the border between two polygons. At the western corner of that polygon, it enters the realm of the third polygon, being the northernmost of the North Volcanic Zone series, it has a trend for providing NS tectonic features, leading the river accurately to the northernmost corner, where the estuary is found.


The Path of Skjálfandafljót River in Iceland

The path of Skjálfandafljót can be traced according to the tectonics related to magma flow. First, the direction of each section follows the tensional matrix, or pressure induced on the primarily diamond-shaped polygons as shown here.

Skjálfandafljót River.

The origin follows an NW aligned path, until it reaches the border of the polygon, then it turns towards NE along the division line. At the northern end of the polygon, the river turns northwards, and crosses the northern corner of the other small polygon as well (1st NS polygon path), repeating the same story within the next polygon (2nd NS polygon path) until it reaches the estuary.

In this way, the relationship between tectonics and river flow can be explained, by referring to the effect of convection rolls below the tectonic plate. https://en.wikipedia.org/wiki/Skj%C3%A1lfandaflj%C3%B3t

The name, Skjálfandafljót, refers to the Skjálfandi Bay, literally meaning Trembling Bay due to frequent earthquakes in the area. The tectonical activity level prbably contributes to the clear features of this particular river alignment.


Old and New NS-Axis of Iceland

The North Volcanic Zone of Iceland is clearly aligned from north to south. But Iceland has another axis like that, farther to the west. The two different axis or lines are of the same nature. Actually, the North Volcanic Zone did replace the Skagafjordur Volcanic Zone. Therefore, the distance between the two axis is exactly 3° from east to west, because both axis have their roots in the convection rolls pattern.

The two NS-axis of Iceland – old and new

The western axis is older, and contains the central polygon of the Icelandic Plateau, where the distance to the edge of the elliptically shaped plateau is the same to the east and west. As shown in other posts, that axis is also centrally located between the main outposts of Icelandic volcanoes, Snæfellsjökull and Snæfell.

We get a geological/geographical bonus by seeing how the glacier Vatnajökull is shaped by the convection rolls framework, as one polygon is colored almost completely white. The other parts of the glacier seem to reach out from that central area. Similar features can also be clearly found for Langjökull, covering the western half of its polygon.


Small Volcanic Zones of Iceland

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.

The smaller volcanic zones and belts of Iceland.

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.