Geology of the Faroe Islands
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Faroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark. They are located north-northwest of Scotland, and about halfway bet ...
lie on the
Eurasian plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...
between
Scotland Scotland (, ) is a Countries of the United Kingdom, country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a Anglo-Scottish border, border with England to the southeast ...
,
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the ...
and
Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
. The islands are of volcanic origin and are made up of three layers of
basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...
, with the top and bottom layers resembling each other. The age of this rock is between 54 and 58 million years, with the oldest material at the bottom.Faroese Faculty of Science
(in Faroese) The Faroe Islands were formed during a period of a few million years, some 55 million years ago in early Paleogene times, when
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
and
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland i ...
started to separate, opening up what became the Northeast
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
. Countless volcanic eruptions built up a huge basalt plateau that covered almost the entire Faroe–
Rockall Rockall () is an uninhabitable granite islet situated in the North Atlantic Ocean. The United Kingdom claims that Rockall lies within its exclusive economic zone (EEZ) and is part of its territory, but this claim is not recognised by Ireland. ...
region, together with the southeastern part of Greenland. In simple terms, each basalt lava flow of today's Faroe Islands represents one volcanic eruption during that time period. Some volcanic eruptions produced voluminous sheet flows each with a thickness of several tens of meters and covering hundreds of square kilometres. Others built up compound lava flows each composed of several thin basalt layers. Some eruptions were violent and produced large volumes of volcanic ash that can be found in between the lava flows. Other strata between the basalt layers contain
volcaniclastic Volcaniclastics are geologic materials composed of broken fragments ( clasts) of volcanic rock. These encompass all clastic volcanic materials, regardless of what process fragmented the rock, how it was subsequently transported, what environment it ...
and other
sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...
s that indicate the long time intervals between eruptions, with rich vegetation taking root in a sub-tropic climate, and with local erosion or deposition of sediments in rivers and shallow lakes. One volcanically silent time period was especially long and resulted in the deposition of several sedimentary layers of varied composition, including strata rich in organic material that subsequently have generated considerable volumes of
coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when ...
. In recent times the coal has been worked from mines in between the basalt flows near the northern villages of Suðuroy. Over the 54 million years since the last flows erupted,
plate tectonics Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...
has slowly moved the Faroe Islands away from the active volcanic region, which today is concentrated in Iceland and along the
Mid-Atlantic Ridge The Mid-Atlantic Ridge is a mid-ocean ridge (a divergent or constructive plate boundary) located along the floor of the Atlantic Ocean, and part of the longest mountain range in the world. In the North Atlantic, the ridge separates the North ...
. Meanwhile, the majority of the Faroe–Rockall Plateau has subsided beneath sea level while erosive forces–especially during the last few million years of alternating
glacial A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...
and interglacial periods–have sculpted the landscape into their present-day shape. The overall thickness of volcanic and intervening rock layers of the Faroe Islands is more than , of which only is located above the present sea level. A deep well in Lopra, Suðuroy, has revealed details of the lower strata.


Notes


References

* Jørgensen, Gunni, and Jóannes Rasmussen. ''Geologisk Kort Over Færøerne Isbevægelser På Færøerne = Geological Map of the Faeoroe Islands, 1:122 000 : Ice Movements in the Faeroe Islands = Ísgongdin Í Føroyum''. DGU series C, no. 7. København: Danmarks Geologiske Undersøgelse, 1988. * Peacock, Martin A. ''Recent Lines of Fracture in the Færoes in Relation to the Theories of Fiord Formation in Northern Basaltic Plateaux''. Glasgow: Jackson, Wylie, 1928. * Rasmussen, Jóannes, and Arne Noe-Nygaard. ''Geology of the Faeroe Islands (Pre-Quaternary)''. København: C.A. Reitzels Forlag, 1970. {{Geology of Europe de:Geologie und Geographie der Färöer