III.—The Petrology of Iceland

Abstract

Kainozoic eruptives, preponderantly of basaltic composition, occupy parts of Scotland, Ireland, Greenland, Spitsbergen, and King Charles Land, the major part of Franz Josef Land, and the entirety of Iceland, the Faeroes, and Jan Mayen. These regions have been grouped together as the Thulean or Brito-Arctic Petrographic Province (fig. l); they represent the relics of an extensive basaltic plateau-land, the greater part of which foundered beneath the North Atlantic and Arctic Oceans in late Kainozoic times. By virtue of its size, central position, diversity, and accessibility, Iceland is perhaps the most instructive region in the whole province. The interest in that country is heightened, furthermore, by the fact that whereas in all the other regions mentioned, with the exception of Jan Mayen, vulcanicity expired before the advent of the Pleistocene and did not recur, Iceland became the theatre of a vigorous resumption of igneous activity which took place in Early-glacial times, and has continued uninterruptedly to the present day.