[O-05] Poster presentations by senior high school students

[O05-P06] Microfossils from the Kushiro Marsh Core,Hokkaido

*Aoi Ohashi¹, *Yuri Hasimoto¹, *Chika Onai¹, Hitomi Saito¹ (1.Gunma Prefectural Ota Girls' High School)

Keywords:ostracode, foraminifera, microfossils, Kushiro Marsh

The sediment samples collected from boring core drilled at middle part of the Kushiro Marsh Hokkaido were studied using foraminiferas, ostracodes, radiorarians and mite fossils. In total, 10 genera and 12 species of foraminiferas and 3 genera and 3 species of ostracodes were identified. The dominant specie of foraminiferas were Trochammina hadai, Ammonia beccarii forma 1, Buccella frigida,Elphidium clavatum and Elphidium subarcticum. The dominant specie of ostracodes was Howeina camptocytheroidea . Most dominant specie of mite fossils was Oppiella nova .The fossils of radiorarians were redepositioned because of there poor preservation.The palaeoenvironment of the Kushiro Marsh was inferred from these fossils. Consequently, these date indicate that there was middle bay in depth 9.30m and inner bay in depth 5.20m. Therefore, the reduction of the Paleo-Kushiro Bay was inferred.