Thegeology ofJan Mayen is part of the largerJan Mayen Ridge — an undersea volcanic ridge that forms the boundary of theIceland Plateau to the northeast — at the junction of theMohns Ridge section with the Jan MayenFracture Zone that crosses it at approximately 90 degrees. North of the island, the sea floor slopes steeply, plunging a depth of greater than two kilometers in the vicinity of Jan Mayen Rift Zone. The region is highly tectonically active, at the junction of the European and American plates. This activity produces volcanism and earthquakes on the island itself.Beerenberg, a 2,277-meter-tall (7,470 ft) volcano rises on the north end of the island, covered in more than 20 glaciers.
Jan Mayen is made up ofbasalt flows andpyroclastic flow relatedmafic deposits. The two most recent eruptions were in 1970 and 1985, although the Central Crater and Egg Island craters on the southern side of the mountain have continuousfumarole activity.[1] Tectonic geologists have identified Jan Mayen as amicrocontinent, which has experienced significant deformation around its boundaries due to sea-floor spreading and the formation of new plate boundaries since thePaleocene, with full separation as a microcontinent in theOligocene. A model published in 2009 suggests a failed ridge offshore oriented toward theFaroe Islands and theAegir Ridge extending northeast of Jan Mayen.[2]
