In geology, the places known as hotspots or hot spots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Their position on the Earth's surface is independent of tectonic plate boundaries. There are two hypotheses that attempt to explain their origins. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. The other hypothesis is that lithospheric extension permits the passive rising of melt from shallow depths. This hypothesis considers the term "hotspot" to be a misnomer, asserting that the mantle source beneath them is, in fact, not anomalously hot at all. Well-known examples include the Hawaii, Iceland and Yellowstone hotspots.Jan Mayen
Jan Mayen (Urban East Norwegian: [jɑn ˈmɑɪən]) is a Norwegian volcanic island situated in the Arctic Ocean. It is 55 km (34 mi) long (southwest-northeast) and 373 km2 (144 sq mi) in area, partly covered by glaciers (an area of 114.2 km2 (44.1 sq mi) around the Beerenberg volcano). It has two parts: larger northeast Nord-Jan and smaller Sør-Jan, linked by a 2.5 km (1.6 mi) wide isthmus. It lies 600 km (370 mi) northeast of Iceland (495 km (305 mi) NE of Kolbeinsey), 500 km (310 mi) east of central Greenland and 1,000 km (620 mi) west of the North Cape, Norway. The island is mountainous, the highest summit being the Beerenberg volcano in the north. The isthmus is the location of the two largest lakes of the island, Sørlaguna (South Lagoon), and Nordlaguna (North Lagoon). A third lake is called Ullerenglaguna (Ullereng Lagoon). Jan Mayen was formed by the Jan Mayen hotspot.
Although administered separately, in the ISO 3166-1 standard Jan Mayen and Svalbard are collectively designated as Svalbard and Jan Mayen, with the two-letter country code "SJ".Jan Mayen Microcontinent
The Jan Mayen Microcontinent is a fragment of continental crust within the oceanic part of the western Eurasian Plate lying northeast of Iceland. At the onset of separation between the Greenland and Eurasian plates 55 million years ago, it formed part of the eastern margin of the Greenland Plate. Propagation of a new spreading center from the Reykjanes Ridge separated this microcontinent from the Greenland Plate. For a short period it formed a microplate, until the Aegir Ridge became inactive, after which it formed part of the Eurasian Plate. The island of Jan Mayen is a much younger feature, formed of volcanic rock, built up at the northernmost tip of the microcontinent.Vesteris Seamount
Vesteris Seamount is a seamount in the North Atlantic Ocean between Greenland and Norway. It lies north of Jan Mayen and rises from 41–43 million years old ocean crust. The reasons for the volcanic activity at Vesteris are unclear and may involve lithospheric processes.
It is a volcano formed chiefly by basanitic rocks and has an erosion-flattened top. The seamount is covered by lava flows and subsidiary cones. The seamount started developing no earlier than 13 million years ago and eruptions continued until the Pleistocene/Holocene transition; there were a number of eruptions in the last 60,000 years. Whether there was Holocene activity 5,000–6,000 years ago or present-day hydrothermal activity is unclear.
A variety of lifeforms are found both on Vesteris Seamount and within its rocks. Layers of sponges and bryozoans cover the upper parts of the seamount and form structures like mounds. This ecosystem has been compared to coral reefs.