The volcanic and sedimentary evolution of the Palaeogene Faroe Islands Basalt Group
Field guide (PDF 6.28 Mb)
Leader: Simon R. Passey (email@example.com), Jarðfeingi (Faroese Earth and Energy Directorate), Faroe Islands.
General Information: The Faroe Islands (Føroyar in Faroese) are located 62°N, 7°W in the NE Atlantic Ocean, ~280 km NW of Scotland and ~400 km SE of Iceland. The capital is Tórshavn, which literally means 'Thor's harbour' and is located on the south-eastern side of Streymoy. The archipelago is made up of ~779 islands and skerries that cover a land area of ~1396 km2. However, there are only 18 main islands (0.84-374.17 km2), 17 of which are inhabited. The greatest distances from north to south and east to west are ~113 km and ~75 km, respectively. There is ~1290 km of coastline and no location is more than 5 km away from the ocean. The landscape of the Faroe Islands has been sculpted by glacial action during the Quaternary, producing a dissected mountainous terrain. Consequently, the islands have an average height of 300 m and the highest mountain is Slættaratindur on Eysturoy at 882 m.
Geological Overview: The Faroe Islands and its insular shelf (to water depths of ~150-200 m) form the Faroe Platform, which has a roughly triangular geometry and is part of the North Atlantic margin, a passive continental margin that extends from the western Barents Sea to offshore west of Ireland. The margin is characterised by numerous sedimentary basins formed by extensional episodes during the Devonian to the Early Eocene. The arrival of the putative proto-Iceland plume beneath Greenland led to widespread volcanic activity during the Palaeocene and Early Eocene (62-54 Ma). The manifestation of this volcanic activity is referred to as the North Atlantic Igneous Province and the Faroe Islands are an exposed remnant of a predominantly subaerial, continental flood basalt domain, the Faroe Islands Basalt Group (FIBG), of this province. On the Faroe Islands, the FIBG has a gross stratigraphic thickness of at least 6.6 km and is dominated by tholeiitic basalt lava flows, subdivided into seven formations based primarily on lithology, but also on geochemistry. The FIBG extends from the Faroe Islands into the Faroe-Shetland Basin for at least 200 km in an easterly to south-easterly direction. The following, from youngest to oldest, are the exposed formations on the Faroe Islands and all shall be visited on the field excursion:
Purpose: This trip will give a comprehensive view of the complexities involved in the development of the Faroe Islands Basalt Group, by focussing on the morphologies of the lava flows and their interaction with sedimentation. The trip will visit the southern island of Suðuroy with the oldest volcanic formations and the central and north-eastern islands where the youngest lava flow sequences are exposed. The trip will not only investigate how the morphologies of the lava flows evolve through time but will also focus on the volcano-sedimentary events (fluvial, lacustrine and mass flows) that punctuate the volcanism and there implication for offshore hydrocarbon exploration. The content of the trip is intended to be general in nature, although detailed discussion will focus on the morphologies and emplacement mechanisms of the lava flows. In addition, there will be a strong emphasis on the terminology used in describing the volcaniclastic lithologies and how the distinction between pyroclastic and volcano-sedimentary units has been accomplished. The emphasis of the trip can be adapted to the interests of participants
Excursion no. 6
Tòrshavn, Faroe Icelands
DURATION: 6 days
TIME: 15 - 22 August