Reconstruction of quaternary paleohydrological parameters: New approaches

The evolution of approaches and methods of reconstructions of the Qunternary ocean paleoenvironments by microfossils containing in bottom sediments is viewed. Authors elaborated new actualistic base for such reconstructions which consists of the databank on planktonic foraminifera tests distribution in the surface sediment layer of the Atlantic Ocean and the complex of mathematical methods for the computer treatment of data. The bank contains the information on contents of 29 species in 381 samples. The mathematical model is based on the factor analysis and the multidimensional spline interpolation. It allows with high precision to reconstruct Quaternary temperatures and salinities for the standart hydrological levels down to 250 m water depth for four year seasons. The examples of the reconstructions are given for the North Atlantic sediment core representing about 300 Kyr. During maxima of the penultimate and ultimate continental glaciations (oxygen isotope stages 8, 6, 4 and 2) the subarctic water mass distributed here. Winter temperatures of the surface water were 1-5 degrees C, the summer ones were 5-7 degrees C. During the interglaciations and the Holocene the winter temperatures were 10-12 degrees C, and the summer ones were 15-17 degrees C. The vertical paleohydrological profiles for the peaks of climatostratigraphical intervals shows that the stratification of the upper 250 meters of the water was higher during cold intervals than during warm ones. Seasonal salinity fluctuations on the 50 m depth did not exceed 0.4 parts per thousand, being minimum in winter and maximum in autumn.