琵琶湖底堆積物の古陸水学的研究

Abstract

In this paper, the writers dealt with the developmental history of Lake Biwa-ko during thelateglacial and the postglacial time. The purpose of the writero are to clarify paleohydrology, paleoclimate, and to establish the late-Pleistocene chronology which is comparable to Europeanand American chronological time table. Discussion was done from chemical, mathematical, physi-cal, and palynological points of view about the various features of core sample of nearly 12 mlong.On the basis of p9llen analytical data, former temperature during the lateglacial time is regard-ed as several degrees in centigrade lower than present one. Although the correlation betweencalcium carbonate amount as an indicator of former temperature and the amount of nutrient saltand of organic matter is indistinct, temperature rise since the lateglacial time is clear. The reasonmight be complicated combination between water environments, organic production and decomposi-tion, turn over rate, source of organic material, and turbidity current in such large lake as Biwa.Because of the existence of thick lacustrine sediments in Lake Biwa-ko, they afford unique in-formation on the fluctuation of the Pleistocene climate in Japan. The writers intend to analyse thefeature of the combination composed by various elements and to accomplish the purpose mentionedabove.