図−14.国際深海掘削計画IPOD 56,57航海の掘削点(日本海溝域.親潮古陸を発見.日本海溝の沈降が2300万年前頃から開始された事実を発見した。(奈須・本座・藤岡・佐藤、1979)
Fig−14. Drilling sites of IPOD Legs 56 and 57. The Oyashio Ancient Landmass was discovered. It was clarified that the subsidence of Japan Trench started about 23 million years ago.(von Huene, R., Nasu, N. et al., Scientists aboard Glmar Challenger for Leg 57,1978)

図−15. 図−14の掘削点438,439で明らかにされた親潮古陸の沈降過程(奈須・本座・藤岡・佐藤、1979)
Fig−15. Subsidence process of the Oyashio Ancient Landmass being clarified by the drilling at sites 438 and 439 in Figure-14(von Huene, R., Nasu, N. et al., Scientists aboad Glomar Challenger for Leg 57,1978).

表−2.過去数十万年の氷期・間氷期の名称
Table−2 Names of the glacial ages and the interglacial ages during past several hundreds of thousand years.