Volcanological Expedition
This expedition was conceived by four first‑year geology students seeking experience in volcanology, glaciation, and expedition organisation. The seven‑week expedition (13 July–27 August 1969) focused on field mapping and geological study of the south‑west slopes of Öræfajökull, Iceland’s largest post‑glacial volcano and one of Europe’s most substantial volcanic structures.
After arriving via Icelandair, the team travelled through central Iceland, visiting Hekla and spending eight days at Landmannalaugar, where they examined classic volcanic features including fumaroles, dacite flows, and the Eldgjá fissure. Severe storms and difficult transport conditions shaped their early travel. They later travelled by sea from Reykjavík to Höfn and then overland to their principal field area near Hof, establishing a base camp at the ruins of Gróf farm—destroyed during Öræfajökull’s catastrophic 1362 eruption.
The geological work documented three major components:
- A vast rhyolite complex forming the mountains Hrútsfjall and Godhafjall, interpreted as a thick extrusive dome with complex flow‑banding, internal folding, and associated plugs and obsidian bodies. Its relationships show erosional unconformities with later basalt successions.
- The Slaga volcanic sequence, comprising older basalts, tuffs, pillow lavas, tillites, and subglacial formations lying beneath or against the rhyolite and reflecting an earlier eruptive phase.
- The Hofsfjall–Fagurhólsmýri succession, a complex stratigraphy of porphyritic subaerial basalts, palagonite tuffs, pillow breccias, and subglacial lava units. Mapping revealed Moberg‑type subglacial eruptive structures, adventive crater rows, parasitic cones, and thick late‑stage grey porphyritic lavas associated with post‑glacial volcanism.
Petrological analysis identified a bimodal volcanic suite dominated by olivine tholeiite basalts and rhyolites, with minor intermediate Icelandites.