AN EVALUATION OF THE LATE WEICHSELIAN SWEDISH VARVE CHRONOLOGY BASED ON CROSS-CORRELATION ANALYSIS

The Swedish varve chronology is based on the correlation of overlappin g varve-thickness diagrams. The traditional visual match between singl e diagrams has been based on, e.g., significant yearly thickness varia tions or specific marker varves, but attempts to verify these correlat ions by statistical methods are rare. To test if these visual correlat ions can be regarded as correct, i.e. statistically significant, we ap plied cross-correlation measures to overlapping varve diagrams from tw o local varve chronologies established in southeastern Sweden. Out of a total of 363 analysed connections, only 78 were found to fulfill the statistical requirements for a perfect match. In 96 cases the statist ical measures suggested alternative placements to the published links. However, we found that for 179 correlations the published varve-diagr am connections are statistically not valid and that in 11 cases the ov erlap between diagrams is too short to allow for valid cross-correlati on analysis. This large number of uncertain varve-diagram correlations in both local chronologies shows that the derailed timing of the ice recession along the south Swedish east coast can only be reconstructed through complementary varve chronological investigations. Our investi gations emphasize the need to corroborate visual varve-diagram correla tions through statistical analyses, before the Swedish varve chronolog y can be regarded as a valid, high-precision time scale.