ABSTRACT: Sequence stratigraphy and tectonics of Tertiary coal bearing basins in northwestern Kyushu, Japan

Iwata, Takao , Teikoku Oil Co., Ltd, Tokyo, Japan

This paper describes the sequence stratigraphy and tectonics of sedimentary basins in the northwestern Kyushu based on offshore seismic, well, and surface geological data. And then regional stratigraphic correlation and tectonics are discussed.

The East China Sea Shelf basin extends northeastward to the north of Goto Islands which mark the northeastern end of the Goto-Senkaku belt, and the Fukue basin is located there. At the south of Goto Islands, there are also developed Paleogene sedimentary basins called the Goto-nada and Amakusa-nada basins. These three basins have the similar sequence stratigraphic framework for the Paleogene strata ranging from late Middle Eocene to Oligocene, and it is sub-divided into four 3rd-order depositional sequences; DS-P3 to -P6 in ascending order. Marine sediments are more predominant among the DS-P3 to -P6 in the southern basins, and they make confident sequence stratigraphic controls. In contrast, The Early to Middle Miocene sequences (DS-N1 and -N2) are distributed only in the Fukue basin. They are mainly composed of continental sediments, and the eastern equivalents in the southern Japan Sea are characterized by deep sea sediments. The Pliocene to Quaternary sequence, named DS-N3, is distributed regionally, and composed of marine sediments.

The upper sequence boundary of the DS-P6 in the Goto-nada basin is an remarkable angular unconformity, although it is not so prominent in the Fukue basin. This angular unconformity seems to have been formed during intense uplift of the Goto-Senkaku belt.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia