ABSTRACT: Tectonic Setting and Basin Characteristics of the Japanese Islands

KANAMORI, KUNIO, and HIROYUKI ARATO, Japan National Oil Corporation, Tokyo, Japan

Japan National Oil Corporation has been conducting the national petroleum exploration program in Japan including wildcat drilling and seismic survey sponsored by the Ministry of International Trade and Industries more than 20 years.

From the results of such exploration activities, Japanese Islands are considered to be divided into eleven geological provinces. Most of them are classified into forearc and backarc basins, as Japanese Islands have been located in the active margin region of the western Pacific since Mesozoic in age. However, the sedimentary basins in the northern and southwestern corners of Japanese Islands have different

basin characteristics, such as foredeep/foreland basin and rift basin. As these basins are located close to northern and southwestern tail ends of Japan Sea, it is considered that they were not strongly influenced by the opening of Japan Sea during Miocene.

The target horizons for petroleum exploration in Japanese Islands are summarized as follows with the exploration results until now:
(1) back-arc basins: sandstones from Miocene to Pleistocene, Miocene volcanics;
(2) forearc basins: sandstones from Cretaceous to Paleogene;
(3) foredeep/foreland basins in Hokkaido Island, northern part of Japan: sandstones from Cretaceous to Paleogene;
(4) rift basins northwest of Kyushu Island, southwestern part of Japan: sandstones from Paleogene to Miocene.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)