The geology, volcanic activity, and age of Bouvetøya, South Atlantic

International Symposium on the Activity of Oceanic Volcanoes. Ponta Delgada, 4-9 August 1980.The volcanic cone of Bouvetøya is built up of two formations. The older formation, of predominantly pyrodastic rocks which are typically hydrothermally altered, is overlain by a formation of mainly lava flows. The rocks present on the island constitute a transitional volcanic series. K/Ar dating indicates that surface rocks were formed as early as 1.4 Ma B.P. The rocks of Nyrøysa are 0.4-0.5 Ma, showing that this platform, which formed between 1955 and 1958, represents a landslide type deposit rather than a recent eruption as has previously been suggested by several workers. Various kinds of evidence suggest that the volcanic activity, or a cycle of activity, of Bvuvet0ya is now in a declining phase.