Notes on the Geology of the Lofoten Islands

Abstract

Abstract T he author described the general appearance of the Lofoten Islands, which have commonly been described as composed of granite, but which, he stated, really consist of gneissic rocks. The scenery of some of the islands on which he did not land resembled that of the Cambrian and Cambro-Silurian districts of Wales and Cumberland; and the interior of Hassel showed dark rounded fells, resembling in outline some of the softer Welsh slates. At Stokmarknæs and at Melbo there is a granitoid rock of pinkish-grey colour, consisting of felspar and platy hornblende, with some mica and quartz. The Svolvaer Fjeld in Ost Vaagö shows a distinctly bedded structure in the cliffs near Svolvaer, the débris at the foot of which consists of a rock resembling syenite, and a quartzite containing a little hornblende and felspar. Bedding was also observed towards the Oxnæs Fjord. The islets near this coast consisted chiefly of a granitoid rock resembling a syenite, showing traces of bedding to the west of Svolvaer. Veins of quartz and seams of hornblende &c. occurred in some of the islets; and the latter were too regular to be explained by deposition in fissures. Near the Svolvaer post-office there was gneiss coarsely foliated, containing hornblende and mica, with pink orthoclase felspar. The author concluded, from his observations, that, with few exceptions, the so-called granites of the Lofoten Islands are stratified, highly metamorphosed rocks—quartzites and gneiss, generally with much fel-spar in the latter, and with more or less hornblende in both—and that they are inferior in position to the gneiss and schists of the mainland, and to the more slaty rocks of the southern and western parts of the same islands. He compares them with some gneiss from Dalbeg on the west coast of the island of Lewis, and thinks it highly probable that they also are of Hebridean age. The remainder of the paper described some raised beaches and moraines. The latter are frequent in the Raftsund at the mouth of tributary glens, and just above the sea-level.