Calibration of the speleothem delta function: an absolute temperature record for the Holocene in northern Norway

The speleothem delta function (SDF) provides a new transfer function betwee n the delta(18)O signal of speleothem calcite and surface ground temperatur e. The function is based on physical principles, relating delta(18)O of the calcite to thermodynamic fractionation, and to the dripwater function, whi ch in turn relates delta(18)O of dripwaters to that of the local precipitat ion and thus to the modification of source water in relationship to the geo graphical position of the site. The SDF must be calibrated against at least two reliable and well-dated palaeotemperature points. The end product is a reconstruction of absolute cave and surface temperatures. The technique is tested using a Holocene speleothem from north Norway, SG93, dated by 12 TI MS U-Th dates. The reconstructed temperature curve is presented and compare d with the GISP2 ice-core record and with the historic record. In both case s the correlation with SG93 is impressive, indicating the validity of the t echnique.