Mantle division in SW-Iceland: How accurately can it be pinpointed?

The difference between division line between plates and convection rolls can be understood quite easily in the south of Iceland.


The central point east of Hveragerði is one of the most appearent in the world, because the N-American and Eurasian plates meet there.

The main division line of lower mantle is oriented SW-NE. The lines between the upper most four layers form an “X”, due to the coincidence that the division lines all meet at 64°N.

Middle - explanation

Each line stands for one of the four convection rolls layers found between 120-410 kilometers deapth. Besides that, the lower mantle cells meet below the black line. For those new to this subject (that is everyone), the intersection zone adds some level of complexity. Everywhere else than at these latitudes, only two layers of upper more convection rolls are found, and only a single set of lower mantle convection rolls. North of 64°N, the layer 1 convection cells have a stronger effect than layer 3. The rolls of layer 1 only reach south to 60.7°N, so south of there layer 3 becomes the upper most layer. At 64°N the thickness of all layers is equal, but north of there layer 1 is thicker than layer 3 and becomes more dominant.


Understanding the mantle division at the NE of Iceland – how to visualize the layers of convection rolls:

As can be seen on this map, two lines are found between Akureyri and Húsavík. The one extending from south of Akureyri towards Skjálfandi Bay just west of Húsavík is the main division line of the lower mantle. It is also the division line of upper most convection cells. These two towns can therefore be introduced as being close to the mantle division line, just like the towns Þorlákshöfn and Hveragerði in the southern part of Iceland.


As there are four layers of convection rolls below Iceland, four sets of division lines appear on the map. This rises the level of complexity, so that those not aware of the layering can not understand the map. Therefore an exhibition was prepared, so the 3D perspective of the layers could be visualized.


Each layer is orianted differently, so sets of lines leading to four different directions appear on the surface.



EW-alignment of Eyjafjallajökull-Katla

One of the most popular hiking routes in Iceland is over Fimmvörðuháls, between the two volcanic sites of Eyjafjallajökull and the Katla caldera. Actually, the two volcanic systems intersect each other. So do the two glaciers covering the sites.

Eyjafjallajökull has elliptical form, with the long axis oriented exactly EW. Farther along that axis to the east, the real Katla is found. Directly north of Eyjafjallajökull is Hekla.

These EW and NS stories are not just a coincidence to be neglected by us all. These stories include a lot of geology to study.

Eyjafjalljökull - Katla - EW axis

In Hveragerði Information Center, a model of this area is exhibited. It gives us a clearer view.


Model of Eyjafjallajökull


And if someone has forgotten how Katla is located on an intersection point, here is a map for review. The top crater of Eyjafjallajökull has a curious position exactly in the middle of the relevant polygon, and thereby in the middle of the East Volcanic Zone.



EW-alignment of the Balkan Mountains

Bulgaria has a central axis along the Balkan Mountains, clearly aligned EW. This gives Bulgaria its square appearance. Comparing the mountainos region with convection cell model, it appears that they have drifted into the central axis enclosure of a row of polygons, therefore adjusted to a perfect EW alignment.

Bulgaria - Balkans

This divides Bulgaria into South and North parts. The coastal polygon is partly responsible for the formation of the Bosphorus.

As previously mentioned, this analysis was made on the occation of a visit to Kavarna with high cliffs at the seaside.

Black Sea - Kavarna

Mnogo dobre!


The central line of the Atlantic extends to the west coast of the Black Sea

Comparing randomly can reveal many things. I went to Bulgaria and noticed some similarities with the surroundings at my home. These cliffs forming the coastline of the Black Sea ought to be there for a reason.

Black Sea - Kavarna

Kavarna in Bulgaria is within a polygon which can be compared with the one at Hekla Volcano in Iceland! Here is how it works:

Black Sea Coast

The back flow line from Hekla (red colour), and the main central line extending from the lower mantle division line, form the sides of the polygon at the coast of the Black Sea.


The 180° of Eurasia between Norway and the Bering Strait

According to the analysis presented here, equator and the parallel of 64°N have mathematically identical outcomes. Even though the rotation provides much more angular velocity at equator, special things appear at 64°N as well.

Mainland of Eurasia 180 at 64N - 02

Some would just show some reflex and start talking about something else, but there is a reason for this.

Norway - Bering Strait

The division lines between mantle convection rolls have a long term guiding effect for the tectonic drift, leading to these results.



Connection between Tungnafellsjökull and Bárðarbunga volcanic sites

It has been noticed that rifts have opened up in the area of Tungnafellsjökull. At the same time, Bárðarbunga has been quite active. According to the layout of the grid of Munroe lines feeding the volcanoes, it looks likely that magma actually flows from the line through Tungnafellsjökull into the magma chamber under the caldera of Bárðarbunga. The flow would follow this arrow:

Tungnafellsjökull - Bárðarbunga

The magma did flow a long way until the eruption of 2014 in Holuhraun started. As shown in former blog post:

Bárðarbunga magma trail