シンポジウム「新生代化石生物温度計の試み-その論理と適用-」 : その背景と課題

抄録

It is very important for paleontologists to estimate the substantial thermal conditons on the basis of fossil-biota, because species extinction and/or appearance may have taken place in relation to environmental changes (e. g. environmental deterioration). Among various environmental factors, paleoclimate (especially thermal condition) has been noticed by many paleontologists. However, there are many problems to be concurred such as "ecogenesis" and "limitation of uniformitarianism". This symposium, as above titled, was held at the Annual Meeting of the Palaeontological Society of Japan in 1992 at Kyushu University. Presentations were arranged in the order of paleobotany, pollen, molluscs, foraminifers, ostracods, diatoms, calcareous nannofossils, radiolarians and so on. For the estimation of paleo-thermal conditions, paleobiogeographic consideration is one of the fundamental bases both in land and marine areas. Japanese Islands have been situated in a characteristic geographic region under various climatic conditions from subtropical to subboreal. As an example of modern marine biogeographic provinciality, Nishimura's division is shown with some practical data on thermal conditions. For the estimation of paleo-temperature, relationship between the total number of species of Cypraeidae (X) and minimum monthly mean surface temperature (Y) are calculated. It seems that paleontologists can contribute more to the geological events from paleontological point of view. Cenozoic major geological events and related paleoclimatological problems are roughly noted.