2007 Volume 113 Issue 8 Pages 417-437
The Tetori Group is distributed in the Hida-Furukawa area. There are diverse opinions about the stratigraphy of the group. So, we restudied the stratigraphy of the group. The group can be divided into six formations: the Tanemura, Numamachi, Sugizaki/Tochio, Taie and Inagoe in ascending order. The geological map of the area was revised to show the distribution of these six formations. These formations are suggested the environments of alluvial fan to shallow marine, shown by deposits transported from the eastern hinterland and fossil evidence. Ammonite indices suggesting Hauterivian to Barremian age occur in the Inagoe Formation. This shows the evidence of the third marine transgression in the Tetori Group. As marine bivalves including inoceramids occur in the Sugizaki Formation as well, two marine transgressions can be recognized in the Tetori Group in this area. Consequently, three sequential marine transgressions: Bathonian to Oxfordian, Tithonian to Berriasian, and Hautervian to Barremian, can be recognized in the Tetori area.
In the eastern part of the Heilongjiang, China, two marine transgressions, the first from late Oxfordian to Volgian (=Tithonian to early Berrriasian) and the second from Barremian to Aptian, are recognizable. Therefore, these marine transgressions in China correspond to these in the Tetori area.
Occurrence of common marine bivalve species and related ammonite species suggests the same realm for both the eastern part of the Heilongjiang, China and the Tetori area, Japan, during Hauterivian to Barremian time. These faunal compositions are different from those of areas in the southwest of Japan influenced by currents from low latitudes. This supports the idea that a peninsula of land was present between both the Tetori area and areas in southwest of Japan. Thus, both areas of the eastern part of the Heilongjiang and the Tetori area were influenced by current from the high latitude.
