A Late Younger Dryas–Early Holocene tephrostratigraphy for Fosen, Central Norway

Abstract

ABSTRACTA number of rapid climate oscillations occur during the Lateglacial–Early Holocene, 15–8 ka BP period and a well‐developed tephrostratigraphy in association with these oscillations increases the possibilities to correlate climate archives around the North Atlantic. This paper presents a tephrostratigraphy for Fosen peninsula, Central Norway. Both the Vedde Ash ca.12.1 ka BP and the Saksunarvatn Ash ∼10.3 ka BP are important isochrones for correlations of Late Quaternary palaeoenvironmental records in the North Atlantic region and have been assigned ages in GICC05. Beside these tephras we have also identified a new tephra, the Fosen Tephra, with a Borrobol‐type geochemistry that occurs above both the Vedde Ash and the Saksunarvatn Ash with an age ∼10.2 ka BP. Several tephras with Borrobol‐type geochemistry have been identified around the North Atlantic. One group is the Borrobol/Penifiler tephras dated to Greenland Interstadial‐1 and another group is dated to the Early Holocene. We suggest that some of the Early Holocene Borrobol‐type tephras and the Fosen Tephra may actually be the same layer. If so, the Fosen Tephra is spread over a large area of the North Atlantic and has the potential to become an important marker for short‐term climate variability in Scandinavia and in the northern hemisphere.