XVIII.—The Geology of Jan Mayen

Abstract

Jan Mayen, so far as at present known, is entirely volcanic in origin. The rocks, therefore, are conveniently grouped with the Tertiary and later volcanics of the Faroes, Iceland, and Scoresby Sound in East Greenland. It should be noted, however, that these three localities are linked together by the Faroe-Iceland Ridge, the water everywhere being shallower than 500 fathoms. Jan Mayen, on the other hand, though lying at the same distance from Iceland as the Faroes, is not on the Ridge, and is separated by depths of over 1000 fathoms. Its position is somewhat to the west of the centre of the Norwegian Sea, and at no great distance from depths exceeding 2000 fathoms.

Changes in arctic vegetation on Jan Mayen Island over 19 and 80 years

“…The non‐glaciated peaks in the south of the island do not exceed 800 m a.s.l., and the centre is relatively flat and low‐lying. Trachybasalt is the most common rock (Wordie ). Since this rock type is highly resistant to weathering, soil development is limited and drainage is rapid as lavas are naturally porous (Russell & Wellington ).…”

The Geology of North-East Jan Mayen

“…In that year Wordie gathered much field data (Wordie, 1926), and brought back a collection of approximately 60 rock specimens subsequently described by Tyrrell (Tyrrell, 1926). These authors refer adequately to the earlier work (Scoresby, 1820;Holmes, 1916, pp.…”

“…Possibly the discontinuous nature of these ankaramitic masses prompted the earlier record of sills (Wordie, 1926) but in no example examined in 1950 could an intrusive origin be proved, and in some localities scoriaceous and slaggy surfaces clearly indicate that the ankaramite was extruded. Thus a period of extrusion of ankaramitic lavas can be recognized between that of agglomerate and tuff-breccia formation and the extrusion of the trachybasalts.…”

The Glaciers of Jan Mayen

“…The wide breach in the crater rim through which the ice field is drained was thought by Jennings to be due to a violent volcanic explosion. Wordie (1926) considered that it might have been formed as a final run-out channel like those which many of the small parasitic cones exhibit. There is no evidence for either of these postulations and it is just as likely that Weyprechtbreen itself was largely responsible for the breaching of the crater wall.…”