JpGU-AGU Joint Meeting 2017

Presentation information

[EJ] Poster

B (Biogeosciences) » B-PT Paleontology

[B-PT04] [EJ] Evolution of Chemosynthetic Ecosystem in Earth History

Sun. May 21, 2017 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall HALL7)

convener:Robert Jenkins(School of Natural System, College of Science and Engineering, Kanazawa University), Hiromi Kayama WATANABE(Japan Agency for Marine-Earth Science and Technology), Takami Nobuhara(Science Education (Geology), Faculty of Education, Shizuoka University), Ryuichi Majima(Faculty of Education and Human Sciences, Yokohama National University)

[BPT04-P09] Boundary of Sakamotozawa formation, Nagaiwa formation and Kanokura formation in a part of Hikoroiti district

*Karin Taira1, Mana Yasui2, Hiroshi Hagiya1 (1.Tokyo City University, 2.Waseda University)

Keywords:limestone, Sakamotozawa formation, Nagaiwa formation, Kanokura formation, Ofunato

Sakamotozawa formation in a part of Hikoroiti district in Ofunato city, Iwate prefecture consists of basal conglomerate, slate rock, limestone and sandstone in the Permian early period.
Sakamotozawa formation is in contact with clino-unconformity of Nagaiwa formation(Mid Carboniferous) and conformity of Kanokura formation(Middle Permian).
In this research, to add a new interpretation to the previous research, we decided more accurate boundary of Nagaiwa, Sakamotozawa and Kanokura formation, and conducted a survey.
As a result, the sandstones in some areas considered to be Nagaiwa and Kanokura formation showed the very similar Ti-Nb ratio to sandstones of Sakamotozawa formation.
In addition, we measured undissolved residue of the muddy limestone from Sakamotozawa formation then it was identified that the amount of Cr·Ni contained in samples are particularly rich rather than the general sandstones of Sakamotozawa formation.
This suggests that there was a provenance which abundant Cr-Ni existed like serpentintite during sedimentation of limestone.