• journal_title：Journal of the Geological Society
• Contributor：Anne Zacke ; Silke Voigt ; Michael M. Joachimski ; Andrew S. Gale ; David J. Ward ; Thomas Tütken
• Publisher：Geological Society of London
• Date：2009-
• Format：text/html
• Language：en
• Identifier：10.1144/0016-76492008-068
• journal_abbrev：Journal of the Geological Society
• issn：0016-7649
• volume：166
• issue：5
• firstpage：969
• section：Research Article

A shark-tooth apatite δ¹⁸O record of the early Palaeogene North Sea reflects changes in regional hydrography by showing variable temperatures and salinities. A 2–4 Ma period in the early Eocene was particularly influenced by substantial surface-water freshening, indicated by a 3–4‰ reduction of δ¹⁸O values. The magnitude of the δ¹⁸O decrease indicates a depletion in ¹⁸O of surface waters by 2–3‰ relative to Eocene mean ocean water. This value is lower than that of coeval lakes reconstructed from freshwater gastropod δ¹⁸O values from the Paris Basin, suggesting that large rivers with high-latitude catchment areas drained into the North Sea. The period of surface-water freshening began close to the Palaeocene – Eocene thermal maximum, when relative sea-level fall, tectonic uplift and basaltic volcanism caused a temporary isolation of the North Sea. North Atlantic and North Sea surface waters became reconnected during a series of early Eocene transgressions.