THE CLIMATIC SIGNIFICANCE OF CLASTIC VARVES IN THE ANGERMANALVEN ESTUARY, NORTHERN SWEDEN, AD 1860 TO 1950

Multiple regression analyses were applied to decipher the correlation between monthly discharge, precipitation and temperature records and a nnual varve-thickness data from river Angstrom ngermanalven north-cent ral Sweden between 1860 and 1950. Over the whole 90-year period we fou nd generally a strong correlation between spring/summer precipitation and annual varve thickness. However, there are clear indications that precipitation during the months of January and March-May was more impo rtant for the formation of varves in the early part of the twentieth c entury, while January, March, April and June seem to have been more si gnificant during the later part of the nineteenth century. Monthly tem peratures and annual varve thickness, on the other hand, did not show any significant correlations over the whole 90-year period, but, when split into 30-year periods, a dependence of varve thickness on October (1862-90) and March (1919-50) temperatures could be observed. Our res ults show that it is important to test each specific varve record agai nst instrumental data sets before any conclusions can be drawn in term s of precipitation and/or temperature dependence. They also emphasize the necessity to correlate varve-thickness records against long instru mental series in order to detect any changing forcing mechanisms.