Alterations of Environment in the Aspect of Quaternary Geology

Abstract

In the Early Pleistocene, the Tertiary fauna and flora had survived, and the Sino-Malayan elements migrated from the south to Japan through the southern land bridges. On the other hand, the first evidences of climatic deteriolation, such the northern temperate species as Pinus koraiensis and Picea Maximowiczii, appeared widely in the Japanese Islands.In the early Middle Pleistocene, the Japanese Islands might have been united with the continent by many land bridges. In the Middle to Late Pleistocene, the glacial eustatic changes of sea level left the marine sediments on the terraces along the coast of the Islands in the rising stage, while they dissected the land bridges in the stage of the lowered sea level.Through the above mentioned processes, the straits between the Islands and the continent had been formed at some parts of the land bridge, which had exerted an influence on the migration and distribution of the fauna, flora and the Man.Elephas naumanni migrated to Japan through the southwestern land bridge, which might have been still complete in the Middle Pleistocene. This migration route was broken by the end of this stage and this elephant disappeared in the early Late Pleistocene.But, in the Latest Pleistocene, Elephas naumanni reappeared in the Japanese Islands together with the cool temperate faunas and floras through a land bridge, which emerged above the lowered sea surface at the site of the former strait.In the Wurm, the Earliest Man of the Japanese Islands, Homo sapiens, distributed widely and left a large number of palaeolithic implements, which are represented by blade, knife blade, point etc. (Table 1). Elephas naumanni became extinct by the end of the latest Wurm.