A multiproxy macrofossil record of Eemian palaeoenvironments from Klaksvík, the Faroe Islands

Abstract

Studies of interglacial successions are critical to our understanding of the environmental history of an area. Analyses of macrofossil remains of plants and invertebrates from Eemian sediments exposed in a coastal cliff section at Borðoyarvík near Klaksvík, Bordoy, northeastern Faroe Islands, indicate that the sediments accumulated in a coastal lagoon. The fossil flora comprises tree birch Betula sect. Albae and we suggest that birch forests were found locally at sheltered sites in the area. Tree birch also occurred on the islands during the mid‐Holocene. The only other woody plant recovered from the Eemian deposit is the dwarf‐shrub Empetrum nigrum, which is common on the islands today. Remains of herbaceous plants are rare but include Viola, Ajuga, Myosotis, Urtica dioica and Ranunculus. The bryophyte flora is species‐rich and most of the fragments belong either to stream species or to species of humid or wet habitats. The fossil flora and fauna also comprise a number of freshwater species that probably lived in an oligotrophic lake and in streams in the catchment of the lagoon. The climate during deposition of the lagoonal sediments was similar to the Holocene oceanic climate of the Faroe Islands. The study adds to our understanding of Eemian environments in the North Atlantic region and helps to fill a knowledge gap about the history of the flora and fauna of the Faroe Islands, which is of biogeographical importance.

Driftwood in the Eemian interglacial lacustrine unit from the Faroe Islands and its possible source areas: palaeobotanical and ichnological analysis

“…The marine diatoms could thus derive from sea spray during storm events, while the trees could have been transported into the lake from a close-by beach or sand bar during such events. The explanation of both freshwater and marine fossil elements is also discussed by Bennike et al (2017). In general, the data show that the environment was favourable for both terrestrial and aquatic plants.…”

“…Palaeoenvironmental resum e Rasmussen (1972) originally misinterpreted the interglacial clayey organic unit in Klaksv ık as glacially reworked marine coastal sediments from the Klaksv ık fjord because of the presence of marine diatoms, although they were in low abundance. Based on geochemical, micro-and macrofossil analyses, Greve (2001), Wasteg ard et al (2005 and Bennike et al (2017) concluded that the sediments (more or less organic gyttjas) were most likely of lacustrine origin formed in a coastal lake/lagoon. The marine diatoms could thus derive from sea spray during storm events, while the trees could have been transported into the lake from a close-by beach or sand bar during such events.…”

“…In general, the data show that the environment was favourable for both terrestrial and aquatic plants. The explanation of both freshwater and marine fossil elements is also discussed by Bennike et al (2017). According to their detailed study, the sediments at Klaksv ık were accumulated in a coastal lagoonal environment that was separated from the open sea by sand bars or a barrier island, from which the terrestrial and freshwater fossils may have been transported into the lagoon by surface run-off and other processes.…”

“…The only data come from Klaksv ık, where the results of dendrological and pollen analyses were published. Only two speciesbirch and crowberrywere found to be native based on the macrofossil remains, for most other plants the long-distance transport from outside the Faroe Islands cannot be excluded (Bennike et al 2017; Table 1). were identified (Rasmussen 1972;J ohansen 1985;Greve 2001;Bennike et al 2017).…”

“…Regarding the glacial history of the site, it is likely that the underlying diamict unit is of Saalian age, the penultimate glaciation, while the other three diamict units most likely represent glacial advances during the Weichselian, with the uppermost diamict correlated with the last ice advance on the Faroe Islands, possibly during the Younger Dryas (Wasteg ard et al 2005;Bennike et al 2017).…”