XIX.—The Petrography of Jan Mayen

Abstract

Jan Mayen is so inaccessible and so infrequently visited that very little geological and petrographical work has been done on the island. Some rocks were collected during the Austrian “Pola Expedition” of 1882–3; and these were described by Scharizer as porphyritic olivine basalts, with one example of ægirine-trachyte. Four analyses were given, but their quality is so poor that they are practically useless for scientific discussion. Washington lists only one of these, and that among the analyses of inferior quality. The only modern petrographic work that has been done on Jan Mayen rocks is the description of an olivine-trachyandesite by Dr Holmes accompanied by a first-rate chemical analysis by Dr H. F. Harwood, which forms a valuable addition to the seven new analyses recorded in this paper.