- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
A brief reconnaissance of the northeastern part of the volcanic island of Jan Mayen in the Arctic Ocean was made in 1950. Three cycles of volcanic activity are recognized, all of Quaternary age. Each cycle began with extrusion of ankaramite; the later lavas in each cycle are trachybasaltic. A genetic relationship between the ankaramite and trachybasalt is suggested by the presence of transitional rocks.