A NEW METHOD FOR IMPROVED DATING OF SEDIMENTAL PALEOCLIMATIC RECORDS USING EVOLUTIVE SPECTRAL ANALYSIS OF ORBITAL VARIATIONS

Spectral time series analysis of luminescent records in speleothems shows that it contains cycles of variations of orbital elements and many shorter solar cycles. Luminescence of organic matter in speleothems depends on solar visible and infrared radiation so it can be used as a proxy index of Solar Insolation (SI). The theoretical calculations of Milankovitch cycles determined that the variations of precession are with period of 23 and 19 ka, and obliquity with period of 41 ka. The most intensive solar insolation cycle is with duration of 11.5 ka. Orbital cycles have duration stable in time. So their pseudo- variations derived by evolutive spectral analysis of sediment records are in fact due only to variations of the sedimentation rate of the sediment. The ratio between the real and pseudo- duration of the orbital cycles gives the sedimentation rate deviation from the mean sedimentation rate of the dated sequence of the sediment. We used it to establish “solid” time scale of sediment records.

Financial support from the INQUA Executive Committee