An early pleistocene glacial-interglacial cycle in the breida vík group on Tjörnes, Iceland:Sedimentary facies, foraminifera, and molluscs

• Published in: Quaternary Science Reviews
• Main Authors: Eiríksson, Jón, Knudsen, Karen Luise, Vilhjálmsson, Már
• Format: Article in Journal/Newspaper
• Language: English
• Published: 1992
• Subjects: Arctic; Breida; Greenland; Tjörnes; Vík; Foraminifera*; glacier; Iceland; north atlantic current; North Atlantic
• Online Access: https://pure.au.dk/portal/da/publications/an-early-pleistocene-glacialinterglacial-cycle-in-the-breida-vik-group-on-tjoernes-iceland(f2ebac7f-211d-4d39-87f2-65b9293c2e77).html; https://doi.org/10.1016/0277-3791(92)90080-R; http://www.scopus.com/inward/record.url?scp=0027037329&partnerID=8YFLogxK

Sedimentary facies, foraminifera, and molluscs are used to reconstruct environmental conditions during the accumulation of the 1.5 Ma Svarthamar Member unit from the Tjörnes sequence, North Iceland. The Tjörnes sequence and the Breidavík Group in particular contains a unique record of Cainozoic glacier variations in the North Atlantic. This is reflected in lithological variations where marine and terrestrial sediments are intercalated between lava flows and pyroclastic rocks on Tjörnes Peninsula. Our results from the Svarthamar Member show that the lithological cycle from glacial to proglacial and then to shallow marine sedimentation coincide with faunal succession, reflecting a change from arctic to boreal arctic or even boreal conditions in the sea around Iceland just after the Olduvai event of the Matuyama. The amplitude of this climatic cycle is comparable to the Late Pleistocene glacial-interglacial cycles in the North Atlantic. This indicates that the North Atlantic current crossed the Greenland-Iceland and Iceland-Faroe ridges during interglacial periods resulting in a periodic northward shift of the polar front during at least a part of the Early Pleistocene.