Toward a tephrostratigraphic framework for the British Isles: A Last Glacial to Interglacial Transition (LGIT c. 16-8 ka) case study from Crudale Meadow, Orkney

Our understanding of the timing and phasing of abrupt climatic oscillations during the Last Glacial to Interglacial Transition (c. 16-8 ka) in terrestrial sequences is limited by a lack of high-resolution, sensitive proxy records with precise chronological data. Lacustrine carbonate records provide an excellent opportunity to address this issue with frequently high depositional rates, and the ability to extract biological and chemical proxy data related to palaeoclimate variations. However, these archives are also some of the most difficult to date due to associated problems with radiocarbon sample contamination. We present the tephrochronological findings from Crudale Meadow, Orkney, one of the most northerly former marl lakes in the British Isles. Thirteen intervals containing tephra are chemically characterised, of which six may be correlated to known eruptions. The results provide a tephrochronological framework from which it is possible to refine the age estimates of less securely dated cryptotephras, and also provide a basis from which to frame ongoing climate reconstructions using state-of-the-art proxy methods. The results presented here demonstrate that Crudale Meadow is a key record in the development of a regional tephrostratigraphic framework, and an important site in developing a refined network of well-dated high-resolution palaeoclimatic records across northern Europe.