Biostratigraphic correlation between the Neogene sections from the Noto peninsula and the offshore Kanazawa 1x well is described in the present paper based on planktonic microfossils.
The main parts of the Taniguchi Formation are considered to be late Early Miocene in age, which is characterized by abundance of Discoaster deflandrei. The Nakanami Formation and the lower part of the Sugata Formation assigned to early Middle Miocene based on calcareous microfossils. The middle to upper part of the Sugata Formation in the Nadaura route is placed in Middle Miocene (KOIZUMI, 1979).The Pliocene Yabuta Formation unconformably covers the Sugata Formation with the absence of the Upper Miocene section.
Showing some local variations, the unconformity penetrated by offshore Kanazawa 1x well is widely traceable in the offshore Hokuriku to San-in sedimentary basins by using the seismic profiles (TANAKA and OGUSA, 1981). From these facts, the main structural movements which formed oil-traps terminated during the latest Miocene to early Pliocene in age.
Moreover the early Pliocene strata are also unconformably overlain by the late Pliocene to Pleistocene strata which are characterized by onlapping patterns in the offshore basins. These patterns suggest that the late Pliocene to Pleistocene strata consist of the sediments deposited during the rise of the sea level. On the Pacific side, the Kurotaki Formation in the Boso Peninsula and the Nobori Formation in the Shikoku district were formed by a transgression in late Pliocene (IKEBE, 1978; ODA, 1977; TAKAYAMA, 1980). These facts suggest that the influence of the late Pliocene transgression extended all over the Japanese islands.
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