History
At the time of the initial break-up along the north atlantic margin, the Jan Mayen Microcontinent formed part of the passive margin developed along the East Greenland margin.
Towards the end of the Eocene period, at about the time marked by chron 17 (Middle to Late Eocene) a new spreading centre began to propagate northeastwards from the Reykjanes Ridge, forming the Kolbeinsey Ridge. During the period when both the Kolbeinsey and Aegir ridges were active, the microcontinent underwent a 30°–50° anti-clockwise rotation. This was caused by the northeastward propagation of the Kolbeinsey Ridge, with simultaneous reduction in the rate of spreading at the southwestern end of the Aegir Ridge. An alternative but challenged model involves no rotation but the development of several short-lived fracture zones cutting through the microcontinent. With both ridges active the microcontinent was also temporarily a microplate.
The Kolbeinsey Ridge reached the Jan Mayen Fracture Zone and therefore linked up to the Mohns Ridge, at about chron 6 (Late Oligocene to Early Miocene). At this time activity on the Aegir Ridge died away and the microcontinent became part of the Eurasian Plate. The northern end of the microcontinent was affected by renewed displacement on the Jan Mayen Fracture Zone. The volcanic island of Jan Mayen only formed in the Pleistocene, possibly related to a hotspot, known as the Jan Mayen hotspot, at the triple junction at the end of the Mohns Ridge.
Read more about this topic: Jan Mayen Microcontinent
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