The geology of MykinesMykines belongs to the eldest part of the Faroe Islands and is formed for about 60 million years ago.
The Faroese basalt is divided into 3 series of eruption, the lower and eldest, the middle and the upper and youngest, The lower is formed by eruption through long fissures of rather fluent lava, which has formed great flat volcanos. In the sound between Mykines and Mykines Holm, Holmgjogv, one can see some of the mightiest on the Faroes, with thickness of about 50 meter.
In between the eruptions there have been shorter and longer periods of quiscence. There have been so long pauses, that there has formed so much vegetation, that it now can be seen as thin layers of coal, even in some places with impressions of conifer (Metasequoia occidentalis). In some places the layers of coal can be seen in the open, for example with Valgarsbrugv, under Ketilsheyggi at about 370 meter above sea level. Here it has been mined in small quantities by inhabitants of Mykines.
At some places on Mykines one can see and easily imagine how the lava as a fluent mass has has formed the rock. This can for example be seen at Kumla, in Hellis Gjogv, below the formation "the face of the man" west of Kumla and on the naked rock on the southern shore of Mykines Holm.
Intermingled with the thin layers of coal there are also layers of tuffclay, sediments of a reddish colour. It can be seen in the bottom of Lendinger Gjogv and many places in the steep southern slopes of Mykines. At other places, as for example on Mykines Holm, one sees layers of clay, basaltic sandstone, sediments and vulcanic ash.
When lava stiffens, it forms prisms perpendicular to the surfaces of cooling. In some places, e g at the "Stonewood" above Korkadalur, these are regular hexagons, in other places more or less regular 4 or 5 sided. The mightier a layer of basalt is, the slower the cooling proceeds. At the "Stonewood", the hight of the columns is about 30 meters and as the cooling has been slow, and the columns are thick. The quicker the cooling, the smaller dimension of the columns, and the smaller, the more susceptible they are to degradation by wear and tear of water and freezing.
Holm Gjogv, the sound between Mykines and Mykines Holm is a part of a dyke. A dyke is a vertical or almost vertical fissure in one or more layers of basalt, in which younger lava has flown and stiffened. In the dykes the columns are horizontal and often of small dimensions and are therefore more susceptible to erosion, often forming a gully or small sounds, grottoes, tunnels or natural bridges.
The first Gjogv westward from Holmgjogv on the southern side of Mykines Holm is a dyke under erosion and running parallel with Holmgjogv. The erosion has gone so far, that there actually is a tunnel straight through the Holm. It can be verified with a hole on the northern side of the Holm, that the tidal stream is running in the same direction as in Holmgjogv and by the fact, that one from a boat can see light shining through.
Where the dyke on the Holm meet the gras slope one can easily see the thin horizontal placed columns, which form the roof of the tunnel through the Holm. One can imagine how there in hundreds or thousands of years time will be two parallel Holmgjovs.
Places of interest on Mykines from a geological point of view.
Mykines Holm.As mentioned before, one can in Holmgjogv see some of the mightiest layers of basalt on the Faroes.
The whole Holm is tilted south east, in the westernmost part about 20 degrees, decreasing to 13 degrees. In the easternmost part of Mykines the tilt is 8 degrees.
The whole Holm is covered by a thick layer of sediments and moraine, probably having its origin in great slopes north of the Holm, now eroded by the sea.
Walking on the naked rock on the coast west of Holmgjogv, one sees moraine, sediments, clay, clay-ironstone and thin layers of coal. The structure of these layers are so, that one can imagine, that part of them has been formed as bottom of shallow waters.
At about the middle of the Holm one can close to the southern shoreline see beautiful formed basalt structures and a little sea and below the crane and the old ramp, by which the goods for the Lighthouse were brought a shore, one can see some mighty and beautiful formed basalt structures.
Westernmost one sees the two stacks, Flattidrangur and Pikarsdrangur, which have great bases, as a sign of lowering of the sea level.
FjørudalsnevFjørudalsnev is the peninsula which is placed between Viðarhelli and Lendingergjogv and upon which the ramp for the boats and the boat houses are placed.
On the top there is gras and moraine and the remnants of more nests (boat houses), which has fallen into the sea for about 50 years ago. South east there are layers of moraine and clay. At about 20 meter above sea level one sees brownish clay, clay-ironstone only of a centimeters thickness. Above this more layers of clay, sand and tuff. At about 20.5 meters altitude there are very thin layers of coal in which there have been found impressions of of conifer (Metasequoia occidentalis).