Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Poster

S (Solid Earth Sciences) » S-GL Geology

[S-GL31] Regional geology and tectonics

Sun. May 20, 2018 3:30 PM - 5:00 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Takeshi Yamagata(Department of Natural Sciences, Komazawa university), Makoto Otsubo(National Institute of Advanced Industrial Science and Technology (AIST), Institute of Earthquake and Volcano Geology)

[SGL31-P03] Fossil/fossil-like textures of the Kanayama limestone bed interstratified in the Cambrian Akazawa Formation, Hitachi district, souther Abukuma Mountains

*Michio Tagiri1, Katsutoshi Hanawa2, Akira Oikawa2 (1.Hitachi City Museum, 2.Geonet Hitachi)

Keywords:Cambrian Hitachi Volcano Plutonic Complex, Kanayama Limestone, Fossil/Fossil-like texture, Archaeocyathus, Echinodermata, trace fossils

The Cambrian Hitachi Volcano-Plutonic Complex (CHVPC) widely occurs in the Hitachi district of the southern Abukuma Mountains. The Akazawa Formation characterized with volcanic rock beds is a member of the CHVPC, and contains the Kanayama Limestone Member. The CHVPC recrystallized to the amphibolite to greenschist facies rocks. The Kanayama limestone crystallized obviously to marble, so that it is difficult to observe a detailed texture of fossil. However, we found many fossil/fossil-like textures from the Kanayama limestone. We report some textures of Archaeocyathus, Coral, spines of Echinodermata or Arthropoda, Brachiopoda, Sponge and trace fossils from this limestone bed. The Kanayama Limestone is very likely a Cambrian formation; therefore, the described fossil textures are the oldest one in Japan.