東亜中生代地史の綜合的考察
スポンサーリンク
概要
- 論文の詳細を見る
Mesozoic palaeogeography and palaeocliniatology of Eastern Asia are discussed here with reference to crustal deformations and the development of floras and faunas.<BR>2) Insofar as the forest composition is concerned, the change of flora is in Eastern Asia found greater within the Mesophyticum than between the Palaeoand Meso-phyticum and this change undoubtedly means the climatic change, if one consider the depauperation of coal measures, vertical distribution of aluminous shales and other aspects in the Permo-Triassic formations.<BR>2) The geoanticlinal upheaval of the Akiyoshi orogenic zone must he the cause of this climatic change, because the zone of upheaval is known to have teen extending from Japan to Tonkin through. Hainan and the terrain where the climate has changed, was embraced by this axis of elevation.<BR>3). In the oscillation zone of strand line after the Akiyoshi paroxysm the luxuriant forest which was the Rhaeto-Liassic type of flora, was introduced as early as Carnic or even in the Ladino-Carnic transition.<BR>4) A trend of research greatly advanced in recent years was in the Mesozoic non-marine faunas on the continent, as the salient facts thus obtained being summarized in this paper. As the result of this research the five distinct faunas called Daido, Jehol, Naktong, Shiragi and Sungari are distinguished in the Koreoa-Manchurian land and their ages determined at Upper Triassic to Liassic, Middle and Upper Jurassic, Lower Cretaceous, Middle Cretaceous and Upper Cretaceous respectively. The palaeogeographic changes through these five epochs are now well deciphered.<BR>5) In conclusion it can be mentioned that the Akiyoshi And Sakawa cycles of orogeny are of prime importance in the tectonic development not only in the festoon islands of Japan but also on the continent of Eastern Asia, and in the history of biota, and climatic change also they bear a great importance.
- 社団法人 東京地学協会の論文