[H-CG24] Earth surface processes related to deposition, erosion and sediment transport

[HCG24-08] Formation process for spherical carbonate and iron concretions

*Hidekazu Yoshida¹, Koshi Yamamoto¹, Hitoshi Hasegawa², Nagayoshi Katsuta³, Sin-iti Sirono¹, Ippei Maruyama¹, Masayo Minami¹, Yoshihiro Asahara¹, Yasushi Yamaguchi¹, Shoji Nishimoto⁴, Niiden Ichinnorov⁵, Richard Metcalfe⁶ (1.Nagoya University, 2.Kochi University, 3.Gifu University, 4.Nagoya City Science Center, 5.Institute of Paleontology and Geology, Mongolian Academy of Science, Mongolia, 6.Quintessa Limited, UK)

Keywords:Spherical carbonate concretion, Spherical iron oxides concretion, Formation process

Spherical carbonate concretions are observed widely varying geological ages in marine sediments throughout the world. In particular, it has commonly spherical shape with highly enriched in CaCO₃, and are hardened and isolated from the surrounding sedimentary rock matrices by sharp boundaries. This feature is reason why isolated carbonate concretion as it is identical in sedimentary rocks and fascinated simply persuade people to think why such rounded concretion in there. It is also known that the concretions often have various kinds of well-preserved fossils at their centres. Here we have describe the formation process and also extesively we have fund the formation of Fe spherical concretions is related on the carbonate spherical concretion. In the presentation, we will introduce those evidences.