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The Aegean Sea is a famous part of the Mediterranean, where the African Tectonic Plate meets with the Eurasian Tectonic Plate. Description of the geological features can be seen here: https://en.wikipedia.org/wiki/Aegean_Sea_Plate

Apart from the deep understanding the Aegean Sea geology already found in scientific articles, the convection rolls pattern tells an untold story. The two trenches (Hellenic Trench and Strabo Trench) are accurately symmetrical, as shown here, aligned 46.4° from north. A closer look would lead to the conclusion that the edges sway a bit. The alignment can actually be pinpointed with calculation, being the alignment (from east and west respectively) of a tectonic roll of the relevant latitude divided with two. The central axis is formed in between convection rolls division lines, marked with intersection point of the northern part of the Sea.

The Mediterranean Sea is characterized by north-south oriented convection rolls, and along the 32nd parallel, the alignment er exactly N-S. This leads to the rather unique symmetry of the Aegean Sea.

The relevant convection rolls are shown superimposed on the Google Earth map. Red lines stand for upwelling between rolls, blue lines stand for downwelling. The upper set of rolls is drawn with slightly wider lines, the lower convection rolls have thinner lines for marking the divisions between them.

The Mid-Ocean Ridge north of Iceland is connected through the Grimsey Oblique Rift. Looking at the Google Map, with a convection rolls system map superimposed, the context becomes quite clear:

The pair of convection rolls extending north of Iceland follow the Kolbeinsey Ridge closely. The eastern convection roll also coincides with the northernmost part of Reykjanes Ridge. (The main part of the Reykjanes Ridge is then shaped by the convection rolls system extending from equator.) A certain aspect of the Tjörnes Fracture Zone is revealed here, namely that it connects the North Volcanic Zone divisional effect with the upwelling division line found north of Eyjafjordur. On the other hand, the Grimsey Oblique Rift extends to the downwelling line found at the eastern side of Kolbeinsey Ridge. This also reveals a certain difference between Kolbeinsey Ridge and the Reykjanes Ridge. Kolbeinsey Ridge resembles a volcanic zone in a way, because it follows a path in between two division lines of the convection rolls. The convection roll is thereby coupled to the tectonic plate, providing resistance to the main tectonic drift of the North American Tectonic Plate in the opposite direction. The Snaefellsnes Volcanic Belt extends over the two convection rolls, thereby also playing a role in the adjustments related to the Kolbeinsey Ridge.

The Kolbeinsey Ridge did break the Jan Mayen Microcontinent away from Eastern Greenland, and the northern end of the ridge is at the so-called Jan Mayen Fracture Zone, as can easily be detected on the map. That does not affect the convection rolls, as they are formed out of slowly flowing mantle material. The properties of convection rolls are quite special, as the mantle there is not molten, but not rigid either. The physical properties are balanced and quite stable, leading to a regular geological arrangement on the surface as well.

Similar oblique rift zones connect the Icelandic volcanic zones with the two mid-ocean ridges, Reykjanes Ridge and Kolbeinsey Ridge. When compared, the length of those two oblique zones appears to be exactly the same, and even the shape of them is alike. Considering that those areas have the same function, as they are reacting to similar effect of the tectonic drift, it is maybe not so strange. When compared to the convection rolls model, this picture emerges:

If put together, these zones form a triangle with three equal sides. The tilt of the triangle corresponds to the divisional vectors of tectonic drift in Iceland. The areas have the characteristics of both volcanic and seismic zones. Reykjanes Oblique Rift Zone is much better known, as it is largely found on land, but the part of it found offshore seems often to be neglected. Recently, more information has been gathered about the Grimsey Oblique Rift, often referred to as the Grimsey Lineament or the Grimsey Seismic Zone.

The end points of both oblique rift zones can be compared, as in the South, the main division line over Iceland is directly E-W oriented, whereas the end point in the North connects to a line directly N-S oriented. The other end points connects the zones with the regularly shaped mid-ocean ridges. The bending of the oblique zones takes place within the grid of polygons in a formidable way. Following the division between tectonic plates along the Reykjanes Ridge looks easy, as it follows one single line with a simple formula. Then is starts bending off the track, leading to the formation of Reykjanes Oblique Rift Zone. Then the E-W part takes over, with the South Iceland Seismic Zone and the East Volcanic Zone, respectively. Following the division along the eastern edge of the East Volcanic Zone leads us to the turning point at Kverkfjöll. Then we have a direct N-S line through the central axis of the North Volcanic Zone, all the way to the Öxarfjordur Bay, where a sharp turn is made for the Grímsey Oblique Rift. As has been dealt with in other posts, there are other faults of the Tjörnes Fracture Zone making the situation out of the north coast of Iceland more complicated, with a triple system of the Dalvik Lineament, Husavik-Flatey Lineament along with the Grímsey Lineament (here dealt with as Grímsey Oblique Rift Zone). From the end point, where a volcano called Storagrunn, the Zone is connected with Kolbeinsey Ridge, completing the main division line between the N-American Tectonic Plate and the Eurasian Tectonic Plate.

Some material about this subject is found here:

.https://www.researchgate.net/publication/225195779_First_results_from_the_North_Iceland_experiment

https://en.wikipedia.org/wiki/Geology_of_Reykjanes_Peninsula

Just as 30° separate main topography of the world at equator today, a 30° pattern can be recognized of Pangea 200 million years ago. The convection currents must then have been coupled and de-coupled in a favorable way so that breakup of the tectonic plate could take place. The breakup occurs mainly along the main division lines of lower mantle large scale convection rolls as shown here.

It is notable that Iceland during that time was located over a large scale downwelling line (the third from left in the drawing). During the breakup, the area where Iceland is now located moved westwards over to the next division line, namely the upwelling line of the center of the present location of the Atlantic Ocean.

.https://en.wikipedia.org/wiki/Pangaea

To clarify further, what has happened after the break-up of Pangea, you can have a look at this drawing of the equatorial plane of the Earth, showing the convection rolls pattern.

To compere with upper drawing, The red marking here corresponds to the second line of the world map above. The upwelling division line did break S-America away from Africa, and then S-America drifted directly westwards over to the other convection roll. The same happened to Africa, but it also drifted northwards, so that now it only spans 30° from east to west. The northwards, and more irregular drift also led to the fact that the coastline is slightly east of the division line, leading to the formation of the Great Rift Valley over the corresponding upwelling large scale division line.

It is interesting that Indonesia has not altered its position according to the map from Wikipedia shown above. The equatorial pattern of 30° intervals is therefore maintained for both 200 Ma and present. For clarity, this drawing can therefore be added:

This is how it looks with 200 million years interval. It would have been nice if we could have measured the drift step by step when the Atlantic Ocean was getting wider at equator. That process is of course still ongoing in general. We can measure the tectonic drift every day now, so this should not be a mystery to be solved. The puzzle of Pangea has been reconstructed accurately because we have thousands of high quality measurements to rely on. Therefore, these two cross sections of equator can be drawn.

It was in the year 1998 that Bjarni Kr. Kristjánsson biologist found a type of amphipoda in Thingvallavatn. It has now got the scientific name Crymostigius thingvallensis. The amphipoda has now also been found at Herðubreiðarlindir in NE Iceland. Similar amphipoda can be found in Ireland and South England in the east, and at the border of Canada and the US in the west. Therefore, it is reasoned that Crymostigius thingvallensis has evolved independently at the location for millions of years, from the time when the two continents of Europe and America were connected.

The area is said to separate the two tectonic plates of N-America and Eurasia. The finding of the Crymostigius thingvallensis is assuring. Today, geologists tend to emphasise the tectonic drift factor, pointing that the main division line is actually south of Thingvellir Rift Valley, so the area is the division line between Hreppar miniplate and the N-American Tectonic Plate. With our amphipoda, it should still be possible to claim that the area is a long term border area due to tectonic drift. That means that favorable conditions are prevalent for millions of years due to the pulling effect of pemanent mantle currents underneath. The rocks seen in the picture are only 9.000 years old, as the rifts constantly renew themselves, and new lava fields add nutrition to this very special lake.

.https://www.thingvellir.is/fraedsla/nattura/lifriki-vatnsins/