Correlation of stadial and interstadial events in the south Swedish glacial varves with the GRIP oxygen isotope record

Abstract

A number of correlated varve sequences from the local varve chronology in southeastern Sweden have been selected to make a 1040 varve years long mean varve thickness curve. Pollen analyses were carried out over an interval of 373 varve years in the northern part of the study area. The pollen stratigraphical data have been divided into local pollen assemblage zones which have been correlated with the radiocarbon‐dated regional pollen assemblage zones. Based on variations in herb and tree pollen content of the analysed varve sequences, it has been possible to identify well‐documented lateglacial pollen zones for southern Sweden, i.e. the Bölling interstadial (GI‐1e), the Older Dryas cold event (GI‐1d) and the early part of the Alleröd interstadial (GI‐1c). The event stratigraphy in this study, based on varying varve thicknesses and the composition of the pollen flora in the varves, has been correlated with the oxygen isotope stratigraphy of the GRIP ice‐core on Greenland between 13600 and 14400 GRIP ice‐core years BP. It is concluded that five decadal warm events and one centennial warm event (15–60 and 100 varve years long, respectively) occur in the clay varve record along with one centennial cold event (150 varve years long), the Older Dryas (GI‐1d).